# Most chatoyant wood species?



## chatometry

Hi everyone

Based on your experience, which wood species show the highest chatoyance?
And which ones the lowest?
Thanks!
Paolo


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## Arn213

Hawaiian Curly Koa highest (curly maple and flame redwood notable mention).

Lowest would be a body wood- alder

Ciao!

Reactions: Informative 1


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## phinds

It depends on the wood. No wood always has good chatoyancy. I've seen pieces of chechem with amazing chatoyancy and other pieces with none. Same with sapele, shedua, and other woods. Quartersawn wood tends to be more chatoyant than flat cut **.

I've seen curly koa that was not chatoyant or barely chatoyant.

EDIT: ** for some species that may not be the case but for most it is.

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## phinds

And by the way, quartersawn oak can (but does not always) have the aspect of chatoyancy that is not shininess but rather a complete change in look. Here you can see the rays go from light on a darker background to dark on a lighter background:





It is largely present on this bowl because of the finish but can sometimes be seen in finely sanded pieces.

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## vegas urban lumber

try anything with a block mottle or beeswing pattern





bee's wing wood figure


bee's wing wood figure



hobbithouseinc.com





or this beauty

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## phinds

vegas urban lumber said:


> try anything with a block mottle or beeswing pattern


Generally, yep, but not always. I've seen (admittedly rarely) some without chatoyancy. I do think that with a gloss finish they do always show chatoyancy.


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## vegas urban lumber

phinds said:


> Generally, yep, but not always. I've seen (admittedly rarely) some without chatoyancy. I do think that with a gloss finish they do always show chatoyancy.


i don't know enough to say all or always, just suggesting it as an option for finding something with great flash


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## Mike1950

big leaf maple


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## Gonzalodqa

Satinwood


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## chatometry

I agree that most often it depends on the specific piece, not just on the species. 
For some species we tested, though, there is some consistency: Iroko always showed chatoyance (samples from 8 different logs), while ziricote never showed it (6 logs). 

So I wonder what the difference is, microscopically, between different species and also within the same specie to cause such variability...

@phinds speaking of oak we see behavior on Quercus Petrae (examples here https://www.chatometry.com/home-page/oak-sessile/)

@Gonzalodqa satinwood (chloroxylon swietenia, right?) is on our to do list for September.

@Mike1950 do you know of companies specialized in bigleaf maple?

Reactions: Like 1


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## Gonzalodqa

Yes and also Zanthoxylum flavum is an “accepted” satinwood

Reactions: Agree 1


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## phinds

chatometry said:


> Iroko always showed chatoyance


I have not found that to be the case:
http://www.hobbithouseinc.com/personal/woodpics/iroko.htm

Some iroko is quite dull.


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## chatometry

Was it finished or fine sanded?


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## phinds

chatometry said:


> Was it finished or fine sanded?


I'm pretty sure at least one fairly dull piece was fine sanded and it may have been more of them. I generally fine sand one side of each sample shown on my site. "Fine sand" in this case my only be to 220 grit though and almost never beyond 400. 

Except for pics of made objects, I don't deal with or show pieces with a finish. Sometime I'll spritz water on a piece to show grain contrast but no finishes.

On this piece, the sanded but unfinished face grain was chatoyant but the side grain was not.


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## Mike1950

chatometry said:


> I agree that most often it depends on the specific piece, not just on the species.
> For some species we tested, though, there is some consistency: Iroko always showed chatoyance (samples from 8 different logs), while ziricote never showed it (6 logs).
> 
> So I wonder what the difference is, microscopically, between different species and also within the same specie to cause such variability...
> 
> @phinds speaking of oak we see behavior on Quercus Petrae (examples here https://www.chatometry.com/home-page/oak-sessile/)
> 
> @Gonzalodqa satinwood (chloroxylon swietenia, right?) is on our to do list for September.
> 
> @Mike1950 do you know of companies specialized in bigleaf maple?


A few. Mostly guitar grade sellers. Almost 3/D. One of my favorites, but I am biased. Ps. None are sanded.

Reactions: EyeCandy! 5


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## chatometry

@phinds 
Thank you.
I will cut a piece off a board I know to be chatoyant and I will sand it to 220 and see what it looks like. 

@Mike1950 
Thank you.
I will look for samples of this wood too.

Reactions: Like 1


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## phinds

Mike1950 said:


> A few. Mostly guitar grade sellers.


Show off

Reactions: Agree 3 | Funny 2


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## Arn213

I think we need to talk about this over…..


phinds said:


> It depends on the wood. No wood always has good chatoyancy. I've seen pieces of chechem with amazing chatoyancy and other pieces with none. Same with sapele, shedua, and other woods. Quartersawn wood tends to be more chatoyant than flat cut **.
> 
> I've seen curly koa that was not chatoyant or barely chatoyant.
> 
> EDIT: ** for some species that may not be the case but for most it is.


You can make this an argument with anything with what you stated. Not all wood species that is deemed to have chatoyant factor will be equal across the board. I have had enough figured Koa that I processed and passed my hands that I can confidently say has some degree of chatoyance and I have had some (still do) that the “shimmer and sparkle” factor is very high. There is a degree of chatoyance that is either low or very high and this is a case by case basis and piece by piece basis. It also doesn’t have to be quarter sawn (well it helps because the flakes helps), bastard cut or flat sawn cut- a good example of these is curly maple. It could be quarter sawn or flat sawn cut and will have chatoyance. Chatoyance from what I have seen and handled- there are ones that has “natural chatoyance” and there are ones with a use of a finish will enhance more of the chatoyance factor.

You also need to separate judging for chatoyance with the same species as exhibit “A” for figured wood and exhibit “B” for non figured wood type. That to me is a fair way to judge it and put it on an even playing field.

















My friend’s recently finished guitar came from this special 400 plus year old Koa from the 2nd photo:

Reactions: EyeCandy! 4 | Agree 1


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## Gonzalodqa

You all are showing off

Reactions: Agree 2


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## phinds

Arn213 said:


> I think we need to talk about this over ...


Arn, I agree w/ everything you said. Also the koa that I was thinking of that was dull was not figured.


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## Arn213

chatometry said:


> For some species we tested, though, there is some consistency: Iroko always showed chatoyance (samples from 8 different logs), while ziricote never showed it (6 logs).


I am having a tough time on your test here on ziricote and whether that is conclusive or just isolated incident. It also depends how this log was processed. If this was properly quarter sawn where you see the landscape + spider webbing + the ray flakes the “chatoyance” factor would be more apparent. But if the log was purely flat sawn cut then you have remissed the other factors that makes a piece of wood chatoyant. 

Can you post the pieces tested?


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## Mike1950

chatometry said:


> @phinds
> Thank you.
> I will cut a piece off a board I know to be chatoyant and I will sand it to 220 and see what it looks like.
> 
> @Mike1950
> Thank you.
> I will look for samples of this wood too.


I sell lots of big leaf


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## chatometry

@Arn213
Thanks for pictures and information on Koa. So, if I get it right, you are saying that Koa always has some chatoyance, sometimes evident and sometimes not so evident; am I right?

Speaking about figure, I want to show two examples from Juglans Regia: the first one has a medium chatoyance numerical value (~15), but it is very evident due to figure ("wavy"?). The second one has a much higher value (~24), but it is less noticeable because the brightness peaks are all phased together, and there is no contrasting reference area. But still if you could make a table out of it, with a proper finish, it would appear dark or light depending on the lighting conditions. 








Speaking about Ziricote, the third picture below shows the most chatoyant specimen we got, which scores a very low value(~8); this is absolutely quartersawn (it is a veneer leftover board). We made a total of 54 measurements, on samples from 6 different logs, all finished in the same way as all our samples (sanding up to 1500 grit).





The fourth example shows a dark Ipe sample, where chatoyance is visible even if the wood is dark.

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## Arn213

chatometry said:


> @Arn213
> Thanks for pictures and information on Koa. So, if I get it right, you are saying that Koa always has some chatoyance, sometimes evident and sometimes not so evident; am I right?
> 
> Speaking about figure, I want to show two examples from Juglans Regia: the first one has a medium chatoyance numerical value (~15), but it is very evident due to figure ("wavy"?). The second one has a much higher value (~24), but it is less noticeable because the brightness peaks are all phased together, and there is no contrasting reference area. But still if you could make a table out of it, with a proper finish, it would appear dark or light depending on the lighting conditions.
> 
> View attachment 213844
> View attachment 213846
> 
> Speaking about Ziricote, the third picture below shows the most chatoyant specimen we got, which scores a very low value(~8); this is absolutely quartersawn (it is a veneer leftover board). We made a total of 54 measurements, on samples from 6 different logs, all finished in the same way as all our samples (sanding up to 1500 grit).
> 
> View attachment 213854
> 
> The fourth example shows a dark Ipe sample, where chatoyance is visible even if the wood is dark.
> 
> View attachment 213855


“You can make this an argument with anything with what you stated. Not all wood species that is deemed to have chatoyant factor will be equal across the board. I have had enough figured Koa that I processed and passed my hands that I can confidently say has some degree of chatoyance and I have had some (still do) that the “shimmer and sparkle” factor is very high. There is a degree of chatoyance that is either low or very high and this is a case by case basis and piece by piece basis. It also doesn’t have to be quarter sawn (well it helps because the flakes helps), bastard cut or flat sawn cut- a good example of these is curly maple. It could be quarter sawn or flat sawn cut and will have chatoyance. Chatoyance from what I have seen and handled- there are ones that has “natural chatoyance” and there are ones with a use of a finish will enhance more of the chatoyance factor”. ^^^^^That is what I am saying and I will stand by that statement all day long.

I like to see the actual veneer photo of that ziricote and the end grain. It doesn’t appear to be true quarter sawn- it’s missing ray flakes. You would have to have a stack of this veneer to be able to have proper read out of the end grain. This is what I am saying that the degree of chatoyant will differ from one piece to one piece, from log to log and even from the areas of the log. Paul brings up something really important that to me visual effects “chatoyance” and when you introduce the quarter sawn cut piece, it will have that additional “sparkle and shimmer”. Here is a piece of true quarter sawn ziricote (left photo) that I have, when the sun hits it, or I rock it to and fro and wet it, you can see the highs and lows of shimmer and sparkle. What makes it more reflective is the presence of the ray flakes in the surface. Interlocked grain will also give you that additional visual textural shimmer and sparkle on certain species- I posted this on a Cuban mahogany piece on a different thread:

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## Arn213

Here is another species that I mentioned as being highly chatoyant. I didn’t post the photo to show off, but to justify what I said and posted earlier on:









^”Flame redwood notable mention” per post #2”. Sinker flame redwood top photo.

Reactions: EyeCandy! 4


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## phinds

You should mention w/ the pics that that is curly redwood. It's always good to have pics labeled, especially for those who may just be skimming the thread. Nice pieces.


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## chatometry

Thank you for the explanation.
The ziricote piece I posted is not a veneer, but a veneer leftover board about 10mm thick. In september I will be able to provide a photo of the endgrain. These boards are usually perfectly quartersawn; in addition I have ~10 more samples from this and from other leftover boards so I can look for one that shows ray flakes.

To sum up, we have one piece (the one you posted) of ziricote that shows chatoyance; however you will agree that ziricote is not famous for its chatoyance, while Koa or Sapele are... right?

So we are saying that this varies from log to log and even between areas of the same log. Would be worth to take a quartersawn log slice like this (link below) and cut it into samples to measure it? This would be a first approach at showing variation within the same log. (it's another specie, but this is to test the concept)









Tavola Palissandro Messicano - Granadillo (cod.: TAGR62) - Seralvo Srl


Questa pianta nasce nell'America Centrale. Questo legno è apprezzato per la colorazione marrone rossastra e viene usato principalmente per strumenti musicali, oggettistica varia ma anche per mobili di prima qualità. E' un tipo di palissandro e viene usato come alternativa al cocobolo. Ha tipiche...




www.seralvo.com





Beautiful flame redwood pieces!!!

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## phinds

Paolo, I'm really glad you joined the forum. This has been (and continues to be) an excellent discussion for any wood forum, so I'm happy we're having it here on WB.

Reactions: Like 1 | Agree 1


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## Jolie0708

Arn213 said:


> Here is another species that I mentioned as being highly chatoyant. I didn’t post the photo to show off, but to justify what I said and posted earlier on:
> 
> View attachment 213858
> 
> View attachment 213859
> 
> ^”Flame redwood notable mention” per post #2”. Sinker flame redwood top photo.


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## Mike Hill

Throwing in my ante. 

Black Walnut - usually not the most, but some do have.






or even birds eye maple - this piece if you move the light enough the eyes almost disappear. 






And I will show off some koa and some quilted BLM - neither are really sanded well.

Reactions: EyeCandy! 1


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## chatometry

@Mike Hill 
Thank you.
We only tested samples from 9 different logs of Juglans Nigra. Results were variable, but never very low or very high: from 12 to 20 (non-chatoyant wood species scores typically <10, while very chatoyant species score typically >20).
Unfortunately we do not have any figured pieces, but this page shows some examples:


Walnut, Black – PZC Chatometry



Speaking of birdseye maple... beautiful piece! I've read something about it coming only from a specific maple specie (Acer Saccharum), but I am still a bit confused. I have some pieces but I'd like to clarify the species before starting to process them. Also, do you know if Europe also produces it?

Finally, the Koa video you posted is amazing!
I wish I could measure the chatoyance on that piece, also on the heart/sap interface... 

For some reason the BLM video you posted does not work on my device :(

Paolo


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## phinds

chatometry said:


> Speaking of birdseye maple... beautiful piece! I've read something about it coming only from a specific maple specie (Acer Saccharum) ...


Absolutely not true. It DOES tend to occur more often in Acer Saccharum than in other maples, but "bird's eye" is NOT a species, it is a type of wood figure and it occurs in some woods other than maple in addition to most species of maple.

https://en.wikipedia.org/wiki/Bird's_eye_figure

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## FranklinWorkshops

This is Chinese toon (toona sinensis) crotchwood and a hollow vessel and bowl turned from it. This was the most dynamic I've seen.

Reactions: EyeCandy! 5 | Way Cool 3


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## Arn213

Mike Hill said:


> Throwing in my ante.
> 
> Black Walnut - usually not the most, but some do have.
> 
> 
> 
> 
> 
> 
> or even birds eye maple - this piece if you move the light enough the eyes almost disappear.
> 
> 
> 
> 
> 
> 
> And I will show off some koa and some quilted BLM - neither are really sanded well.


Spam and pineapple on that yummy slice of koa- extra cheese please!

Reactions: Funny 1


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## chatometry

phinds said:


> Absolutely not true. It DOES tend to occur more often in Acer Saccharum than in other maples, but "bird's eye" is NOT a species, it is a type of wood figure and it occurs in some woods other than maple in addition to most species of maple.
> 
> https://en.wikipedia.org/wiki/Bird's_eye_figure


Thanks for the clarification.
The issue I am having with Maple is that in Italy dealers only name it "Acero" (Maple), never providing information on the exact species. So I have many samples, from Europe and North America, labeled as "acer spp." :(

@FranklinWorkshops fantastic!!!
Is there any chance you have a cutoff from that board? Even just a 130*40*2mm strip would be enough to measure its chatoyance.


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## FranklinWorkshops

Paolo, that entire board was purchased by Sean. Here is the thread about it. https://woodbarter.com/threads/david-ellsworth-piece.42536/
Maybe Sean has a small piece left. I do not.


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## chatometry

Thank you @FranklinWorkshops


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## phinds

Everyone please refer to this thread:

https://woodbarter.com/threads/call...mall-wood-small-samples-for-chatoyance.46290/


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## chatometry

Thanks again @phinds 
I'd like to add our point of view to the discussion. Chatoyance is often discussed together with figure (thanks for the examples everyone posted).
But... let's consider a tiny spot on the surface; as an example, let's take a tiny square on the flame redwood posted by Arn213.



On this small are there will not be any figure, but still it will change is brightness depending on the lighting condition. 
So the first question would be: how much does the brightness change on this tiny spot when it is lighted from different directions?
This is a bit like density: it's some sort of microscopic property of the material. 
Technically, this property causes the brightness to be a two-peaked function of azimuth lighting direction.
Going to a larger scale, when these peaks are all in phase there will be a uniform change in brightness, such as in this Makore sample (1500-grit sanded, no finish):




When these peaks have different phases across the board you get all sorts of figures, such as curl on this Purpleheart sample (1500-grit sanded, no finish):




Or this (typical) interlocked grain on Sapele (1500-grit sanded, no finish):




It is clear that figure makes chatoyance much more evident...and chatoyance makes figure much more evident too. Simply put, chatoyance provides the change in brigtness, while figure highlights it providing contrasting areas.

Then one might argue that figures such as curl or birdseye cause an overall alteration of fibers with an impact on chatoyance... This is possible. So far, the highest chatoyance readings we have are on straight-grained sections, but this is not conclusive. We will pick a board with both figured and plain areas, cut samples and measure them to see what the numbers are.

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## phinds

I agree w/ your statements, but ...


chatometry said:


> So far, the highest chatoyance readings we have are on straight-grained sections


What do you mean by straight grained? Quartersawn? Flat cut? Rift cut? ALL of those can be straight grained and all of them can have, for example, curly figure. So, to my mind, just "straight grained" is vague. Am I missing something?


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## Nature Man

chatometry said:


> Thanks again @phinds
> I'd like to add our point of view to the discussion. Chatoyance is often discussed together with figure (thanks for the examples everyone posted).
> But... let's consider a tiny spot on the surface; as an example, let's take a tiny square on the flame redwood posted by Arn213.
> View attachment 214128
> On this small are there will not be any figure, but still it will change is brightness depending on the lighting condition.
> So the first question would be: how much does the brightness change on this tiny spot when it is lighted from different directions?
> This is a bit like density: it's some sort of microscopic property of the material.
> Technically, this property causes the brightness to be a two-peaked function of azimuth lighting direction.
> Going to a larger scale, when these peaks are all in phase there will be a uniform change in brightness, such as in this Makore sample (1500-grit sanded, no finish):
> View attachment 214129
> 
> When these peaks have different phases across the board you get all sorts of figures, such as curl on this Purpleheart sample (1500-grit sanded, no finish):
> View attachment 214130
> 
> Or this (typical) interlocked grain on Sapele (1500-grit sanded, no finish):
> View attachment 214131
> 
> It is clear that figure makes chatoyance much more evident...and chatoyance makes figure much more evident too. Simply put, chatoyance provides the change in brigtness, while figure highlights it providing contrasting areas.
> 
> Then one might argue that figures such as curl or birdseye cause an overall alteration of fibers with an impact on chatoyance... This is possible. So far, the highest chatoyance readings we have are on straight-grained sections, but this is not conclusive. We will pick a board with both figured and plain areas, cut samples and measure them to see what the numbers are.


Do you venture into analysis using black lights? Chuck


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## chatometry

@phinds 

By "straight grained" I meant something with no figure highlighted by chatoyance, like "curl", "wavy", "quilt": these all mean that there is an underlying fiber distortion. 

In fact the angular (azimuth) location of the brightness peaks reveals the fiber direction. 

This is very well explained in this article:






IET Digital Library: Estimating fibre orientation in spruce using lighting direction


Softwood is almost entirely composed of fibres and its physical properties depend on their orientation. A method is proposed to estimate the average fibre orientation at each pixel in the inspection image. In this study it is shown that finished wood has distinctive reflectance properties that...




digital-library.theiet.org





In our research we saw the same two-peaks chart for all the specimen of all the species we tested!!! This is just one of hundreds of similar charts we got:





(Theta is the azimuth direction of lighting and Y is average of brightness(theta)/min brightness multiplied by 100)

When we tested other things, like plastic, paper, wood endgrain, etc we did not get that chart shape.
So this is a confirmed way of measuring fiber direction. 

As the article explains, the peak angular positions should also tell something about whether fiber distortion is "from side to side" of a surface, or "in and out" of the surface. We did not investigate further on this point though, so I am unable to tell whether a specific figured sample has fibers that go "from side to side" or "in and out".

This was even modeled to provide procedural textures for computer graphics, as explained in this other article:





__





Simulating the structure and texture of solid wood






www.cs.cornell.edu





So, as far as I understand, when there is a curly figure, or any other figure, there also is some fiber distortion. 

I hope I replied, but if I didn't please let me know and I will try to clarify.

@Nature Man no we never tried that. Do you have any / have you ever tried it on a chatoyant board?
Interesting thought.

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## Nature Man

chatometry said:


> @phinds
> 
> By "straight grained" I meant something with no figure highlighted by chatoyance, like "curl", "wavy", "quilt": these all mean that there is an underlying fiber distortion.
> 
> In fact the angular (azimuth) location of the brightness peaks reveals the fiber direction.
> 
> This is very well explained in this article:
> 
> 
> 
> 
> 
> 
> IET Digital Library: Estimating fibre orientation in spruce using lighting direction
> 
> 
> Softwood is almost entirely composed of fibres and its physical properties depend on their orientation. A method is proposed to estimate the average fibre orientation at each pixel in the inspection image. In this study it is shown that finished wood has distinctive reflectance properties that...
> 
> 
> 
> 
> digital-library.theiet.org
> 
> 
> 
> 
> 
> In our research we saw the same two-peaks chart for all the specimen of all the species we tested!!! This is just one of hundreds of similar charts we got:
> 
> View attachment 214150
> 
> (Theta is the azimuth direction of lighting and Y is average of brightness(theta)/min brightness multiplied by 100)
> 
> When we tested other things, like plastic, paper, wood endgrain, etc we did not get that chart shape.
> So this is a confirmed way of measuring fiber direction.
> 
> As the article explains, the peak angular positions should also tell something about whether fiber distortion is "from side to side" of a surface, or "in and out" of the surface. We did not investigate further on this point though, so I am unable to tell whether a specific figured sample has fibers that go "from side to side" or "in and out".
> 
> This was even modeled to provide procedural textures for computer graphics, as explained in this other article:
> 
> 
> 
> 
> 
> __
> 
> 
> 
> 
> 
> Simulating the structure and texture of solid wood
> 
> 
> 
> 
> 
> 
> www.cs.cornell.edu
> 
> 
> 
> 
> 
> So, as far as I understand, when there is a curly figure, or any other figure, there also is some fiber distortion.
> 
> I hope I replied, but if I didn't please let me know and I will try to clarify.
> 
> @Nature Man no we never tried that. Do you have any / have you ever tried it on a chatoyant board?
> Interesting thought.


I have not tried this, but have known a couple of advanced woodworkers that used both black lights and ultra violet cameras to highlight features in wood. Chuck


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## 2feathers Creative Making

I would venture to say, most wood workers are talking about the reflective parts of wood that catch your eye when using the term chatoyancy; while the scientific types are talking about what amounts to the reflectivity of a particular species of tree regardless of figure and visual interest. 

The figure will however stand out much more in a more reflective species of tree which is what makes this conversation immensely valuable to woodworker and/or scientist. In a low chatoyant species, I would expect figure to be much harder to "pop" 
Grain on the other hand will "pop" based more on the porosity of the species and the spacing and size of the pores. 
Am I correct in the assessment of the conversation to this point?
This will help me figure out which pieces may be more helpful to the science being pursued as opposed to just being of individual interest to a woodworker.


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## phinds

2feathers Creative Making said:


> I would venture to say, most wood workers are talking about the reflective parts of wood that catch your eye when using the term chatoyancy; while the scientific types are talking about what amounts to the reflectivity of a particular species of tree regardless of figure and visual interest.


I don't think so. Chatoyance in wood does not refer to a species it's just a description of a particular piece of wood.


> The figure will however stand out much more in a more reflective species of tree which is what makes this conversation immensely valuable to woodworker and/or scientist. In a low chatoyant species, I would expect figure to be much harder to "pop"


I disagree. There are species where the figure pops beautifully and it has nothing to do with reflectivity but with the grain pattern and, as you say below, the porosity.


> Grain on the other hand will "pop" based more on the porosity of the species and the spacing and size of the pores.
> 
> 
> 
> Am I correct in the assessment of the conversation to this point?
> This will help me figure out which pieces may be more helpful to the science being pursued as opposed to just being of individual interest to a woodworker.
Click to expand...

That question I'll leave to Paolo.

Reactions: Thank You! 1


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## chatometry

I think maybe I am using some terms in a wrong way, so let's try to clarify them first.

Instead of "chatoyance" I will use "anisotropic reflectance", which is the technical term I've seen used in scientific articles.
Anisotropic Reflection represent the variation of brightness of a given spot depending on the relative azimuth position of light and observer. From the testing perspective, imagine you have a camera looking perpendicularly at a wooden surface, and a light source lighting the surface and rotating around the camera optical axis. This brings a constant amount of light to the surface, so if you measure the brightness of glossy plastic (example) you always get the same value for all light angular positions. But if you do it with wood you ALWAYS get a variable result, with the two-peaked chart shown above. This effect is sometimes so small that it can't be seen by the naked eye (like on Olivewood), and sometimes it is evident (Sapele, Iroko, etc...).
This looks to me like a property of the material itself, like density or thermal conductivity. And this is what we are measuring.

Now I will ask a few questions so that we can clarify the terms "chatoyance" and "figure": 
In which of the following figures A, B, C, D, E, F and G do you see "chatoyance"? And in which one(s) do you see "figure"?
(all samples sanded to 1500 grit & no finish)




A - Makore





B - Olive





C - Ziricote





D - Aniegre





E - Douglas Fir





F - London Plane





G - again Makore

@2feathers Creative Making
You wrote "This will help me figure out which pieces may be more helpful to the science being pursued as opposed to just being of individual interest to a woodworker."
At this stage we are trying to see which wood species (or groups) have the highest and lowest values on average. So please pick random pieces, and avoid selecting them based on their chatoyance. 

Paolo


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## 2feathers Creative Making

chatometry said:


> I think maybe I am using some terms in a wrong way, so let's try to clarify them first.
> 
> Instead of "chatoyance" I will use "anisotropic reflectance", which is the technical term I've seen used in scientific articles.
> Anisotropic Reflection represent the variation of brightness of a given spot depending on the relative azimuth position of light and observer. From the testing perspective, imagine you have a camera looking perpendicularly at a wooden surface, and a light source lighting the surface and rotating around the camera optical axis. This brings a constant amount of light to the surface, so if you measure the brightness of glossy plastic (example) you always get the same value for all light angular positions. But if you do it with wood you ALWAYS get a variable result, with the two-peaked chart shown above. This effect is sometimes so small that it can't be seen by the naked eye (like on Olivewood), and sometimes it is evident (Sapele, Iroko, etc...).
> This looks to me like a property of the material itself, like density or thermal conductivity. And this is what we are measuring.
> 
> Now I will ask a few questions so that we can clarify the terms "chatoyance" and "figure":
> In which of the following figures A, B, C, D, E, F and G do you see "chatoyance"? And in which one(s) do you see "figure"?
> (all samples sanded to 1500 grit & no finish)
> 
> View attachment 214170
> A - Makore
> 
> 
> View attachment 214173
> B - Olive
> 
> 
> View attachment 214174
> C - Ziricote
> 
> 
> View attachment 214171
> D - Aniegre
> 
> 
> View attachment 214172
> E - Douglas Fir
> 
> 
> View attachment 214176
> F - London Plane
> 
> 
> View attachment 214175
> G - again Makore
> 
> @2feathers Creative Making
> You wrote "This will help me figure out which pieces may be more helpful to the science being pursued as opposed to just being of individual interest to a woodworker."
> At this stage we are trying to see which wood species (or groups) have the highest and lowest values on average. So please pick random pieces, and avoid selecting them based on their chatoyance.
> 
> Paolo


To me, chatoyance alone on (a) .
Mainly figure with negligible chatoyance on (b) and (c)
The remainder have both with (e) having a very simple figure , more just grain pattern.

Will randomize. If I add a medium or high figure piece, it will be as an additional piece.


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## Mike Hill

Ok, my brain processes information (stimuli) in a very pragmatic way - some may say in a weird way - they are entitled to their opinion! LOL. I am trying to get my brain around this. Maybe the photographer and painter in me is getting in the way. 

The law of reflectance states that the angle of reflection equals the angle of incidence - i.e. as you move the light source the angle or rather angles of reflection changes. Is this another descriptor for "anisotropic reflectance"? In each of the sample above, I see that happening. Sometimes it happens in the summer wood, some times in the spring wood. Some samples have more reflectance than others. 

If you have ever set up photographic lighting - you have to be aware of it. In photography, to set the various "correct exposures" you have to first measure the reflected light. If you make the location of your light spot meter and subject constant as well as the distance of your light from the subject, but move only the light from one side to the other in an arc - just about any surface where you are measuring the reflectant light will vary in amount of light "strength" measured as you move the light. I always thought this was because of the law of reflectance - the angle of incidence is changing so the angle of reflected light is changing and the apparent brightness of the surface changes due to more or less light reflecting to the meter or your eyes. I suppose in a perfect world you'd only see dark and bright, but no surface is perfectly polished and no light beam is perfectly focused so we see variations of light and call it high key (extreme contrast - largely pure black and pure white) or low key (minimal contrast - whole spectrum of tonal variations). Extreme high key lighting of a face happens when the light is at the plane of the subject. Low key lighting is usually at 90 deg to the plane of the subject. 

My question is not so much whether or not there is chatoyance - I can see and experience it - and it can be measured in some way or another, but what causes the chatoyance. From the above paragraph, I could ascertain that there would be some kind of differing alignment of something within the structure of the wood itself. Also does it change with the spectrum of light used? Would a highly focused laser light change your readings?


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## chatometry

@Mike Hill
I am glad that you asked all of these questions. I did not know about the "high key" or "low key" terms, but all this exposure topic has been dealt with. Let me explain...

In theory analyzing chatoyance means investigating the effects of different relative positions of four players:
- wood surface
- light source
- observer
- fiber direction
This was done in the past in the US using the Stanford Spherical Gantry.
However, this approach involves too many degrees of freedom, thus requiring an immense amount of measurements, which is not practical for systematic testing purpose.

Therefore, a much simpler mechanical setup was conceived independently by at least two people, which consists of:
1) place a camera looking perpendicularly at a wood surface (i.e. the camera optical axis is perpendicular to the surface)
2) put a light source on a platform which rotates around the camera optical axis. This rotation is angle "theta", or "azimuth".
3) shoot pictures for different theta angles.

This way, the point where the camera axis intersects the wood surface will experience constant incidence angle and light intensity. 
So the light is not moving "over" the surface, but "around" the surface!
This is very difficult to notice on the gifs I posted so far because the high-grit sanding provides a very glossy surface, preventing all diffuse-reflection issues.
On Fiemme Spruce, though, fine sanding did not provide enough gloss to prevent all glare and the gifs somehow reveal the light rotation path:



(Fiemme Spruce - 1500-grit and no finish)

There is surely something within the structure of the wood itself, but I am still curious as to why this is much more evident on some species/pieces...

We did not investigate the effect of spectrum, but the way results are calculated requires white light (with adequate white balance).


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## phinds

Mike Hill said:


> The law of reflectance states that the angle of reflection equals the angle of incidence


Yes, but that's only for an ideal surface and the flaw with taking this approach is that it assumes that the wood surface is like an absolutely flat plane, but it is not. Wood has structure at the micro level which causes it to reflect light differently depending on the angle at which it is viewed. If you look at the surface of the Earth from far enough away it appears flat, but when you get up close enough you see that it has peaks and valleys. Wood is like that too.

That's why you will sometimes see a different degree of chatoyancy if you move a piece at a right to left angle to your eyes vs an up to down angle. Also, the structure can vary from one part of the wood to an adjacent part. Thus the color change in oak ray flakes vs the surrounding wood and the difference in heartwood vs sapwood in, for example, many of the pine/larch/fir species.

Sanding gets rid of at least the biggest variations in the peaks and valleys in the wood which is why well sanded wood will show chatoyancy that rough wood won't.


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## Mike1950



Reactions: EyeCandy! 4


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## Mike1950

Mike1950 said:


> View attachment 214232


Sanded to 120


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## Eric Rorabaugh

Dang Mike. What is that?

Reactions: Like 1


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## Mike1950

Eric Rorabaugh said:


> Dang Mike. What is that?


It is a secret.... but I had a big slab. Wife confiscated it.

Reactions: Funny 2


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## Mike1950

Eric Rorabaugh said:


> Dang Mike. What is that?


Waiting for Paul to chew me out for not labeling...

Reactions: Funny 4


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## Eric Rorabaugh

Well whatever it is, it's drooling gorgeous!

Reactions: Thank You! 1 | Agree 1


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## phinds

Mike1950 said:


> Waiting for Paul to chew me out for not labeling...


(&#*%&[email protected]#()_)T(@J !!!! LABEL THE DAMN THING !!!

How was that?

Reactions: Funny 4


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## chatometry

Good stuff...

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## Mike1950

Eric Rorabaugh said:


> Dang Mike. What is that?


Mango

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## Eric Rorabaugh

NICE!

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## chatometry

2feathers Creative Making said:


> To me, chatoyance alone on (a) .
> Mainly figure with negligible chatoyance on (b) and (c)
> The remainder have both with (e) having a very simple figure , more just grain pattern.


Agreed. 
There should be two different words:
One for "figure" related to colour (like Olive, Ziricote, etc) and one for "figure" related to chatoyance (like quilted Maple, mottled Makore, etc)!


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## Mike Hill

First off, it should probably be said that what we call "figure" is not always wood-grain (growth rings). Would it suffice to say that all wood-grain is figure? Chatoyance is not wood-grain, but can be figure. 

I go back to an earlier question - can it be determined (or has it been determined) what is the "cause" of chatoyance? Is it cell walls? Pores? Chemical composition? Minerals present? Amount of moisture in the wood? Little green men with ray guns trying to shoot out the lights?

Ok, I now understand that your light is traversing a circle around the lens axis. That changes things. Out of curiosity - at what distance above the plane of the wood does the light travel and at what distance is your equipment from the wood? So, assuming the light travels on a plane parallel to the plane of the wood, then the angle of incidence is the same for 360 deg of travel. Lets call that the apparent angle of incidence. Yet the angle of reflectance appears to change. This same phenomenon happens when the light travels in an arc above the wood from side to side 180 deg. In that instance, the angle of incidence is changing. In the same piece of wood are your measurements different between the two light travels?

Allow me to postulate that the changes in the light measured are due to the same effect - the change in the angle of reflectance. If that is not correct, please correct me. In the light moving in the arc - all factors are constant but the light and the angle of incidence. In your circular motion, everything appears to be constant (except of course the light - but the apparent angle of incidence to the plane of the wood is constant). Yet the reflectance changes lead me to deduce that something in or on the wood is not constant that is such that changes the *ACTUAL* angle of incidence and therefore the angle of reflectance.

With my limited knowledge of wood - I assume that unfinished wood is opaque and light does not travel THROUGH the surface and hits something and reflects back out (as a mirror), but acts more like a polished piece of metal. So to me, there is something about the surface of the wood that causes chatoyance. But the surfaces of the different woods you used are superficially prepared the same - so that leaves something in the wood itself.

I know very little about the structure of wood, but would assume those woods that reflect more light - have more pronounced chatoyance - do they have more unity? Do they either have more of what reflects the light or what reflects the light is more lined up and/or denser- so to speak. Those woods/pieces of wood with less apparent chatoyance either don't have as much of what reflects or what they do have is not lined up or as dense or somehow otherwise disperse (less focus) the reflected light.

Does the chatoyance increase of decrease with the type of cut - i.e. rift, quarter, plain, live? Does it change due to where from the tree the wood comes from - near core - near bark? Is it same with a transparent finish? It seems to be more apparent often in places of stress in the tree - crotches, downhill sides, in buttresses, etc.... Or do those stresses bend that which causes the chatoyance into different configurations that change the angle of reflectance?

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## T. Ben

Boy I wish I could retain half of this thread!

Reactions: Agree 1


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## phinds

Mike Hill said:


> Chatoyance is not wood-grain, but can be figure.


No, it cannot. "Figure" is specifically things like ribbon stripe, curly, etc. Chatoyance can ENHANCE figure but it is not figure.

Also, I take it you do not agree w/ my post #50.


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## Mike Hill

I have purposefully not gone to look for some standardized definition of "figure". I am currently sitting in front of a sample of rather fabulous curly koa. If I look for wood grain - it is almost non-existant. Yet it is considered "highly figured" and sells for an amount commensurate with the amount of figuring! If I look at the piece at 90 deg from the apparent surface plane - I see a lot of "figure". If I look at the piece at some angles of 45 deg and less, the figuring almost disappears. To me, what they are measuring is generally the amount of light reflecting from the surface of the wood at differing positions of the light. If in the cycle of the light if the surface of the wood is dark is NOT because there is no light reflecting off of if, but rather the light reflecting is not being reflected into our eyes, camera, meter, etc... Or, since this is not a perfect world and we don't have perfect surfaces, then I guess it would be more correct to say - if the wood is darker during the light cycle, then the prevalence of light is reflecting elsewhere and if it is lighter then the prevalence of the light is being reflected into our eyes, camera, meters, etc.... The only reason we would normally know that there is curl, or ribbon stripe is because of the differing quantities of reflected light. There may be some structure to the wood that microscopically we might be able to ascertain - but normally, at normal viewing, we would not know there was any "figure" without the differing reflections. So I'm not sure you can separate the two. Can chatoyance exist with out "figure" - it appears so. But can certain figuring exist without chatoyance - I guess they can, but you might not be able to see it.


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## chatometry

Mike Hill said:


> I go back to an earlier question - can it be determined (or has it been determined) what is the "cause" of chatoyance? Is it cell walls? Pores? Chemical composition? Minerals present? Amount of moisture in the wood? Little green men with ray guns trying to shoot out the lights?


I think literature says it is due to cell walls, but I am not expert on this. Surely it has to be something common to both softwoods and hardwoods.



Mike Hill said:


> This same phenomenon happens when the light travels in an arc above the wood from side to side 180 deg. In that instance, the angle of incidence is changing. In the same piece of wood are your measurements different between the two light travels?


We cannot run this kind of test. However it would be hard to find a meaning in such data, as you would have a variable light intensity, all sorts of glare issues, etc.



Mike Hill said:


> Yet the reflectance changes lead me to deduce that something in or on the wood is not constant that is such that changes the *ACTUAL* angle of incidence and therefore the angle of reflectance.


You are thinking of a surface made of plenty of micro-mirrors oriented at an angle which is different from that of the nominal surface plane. This may be true. However I am more inclined to thinking that fibers reveal a different colour depending on light direction. But I don't know, it would be interesting to find out.



Mike Hill said:


> so that leaves something in the wood itself


Absolutely. There is an undeniable difference between wood species.



Mike Hill said:


> I know very little about the structure of wood, but would assume those woods that reflect more light - have more pronounced chatoyance - do they have more unity? Do they either have more of what reflects the light or what reflects the light is more lined up and/or denser- so to speak. Those woods/pieces of wood with less apparent chatoyance either don't have as much of what reflects or what they do have is not lined up or as dense or somehow otherwise disperse (less focus) the reflected light.


I don't know. At the moment the question (for those who know a lot about wood) is: what do {Iroko Khaya Sapele Okoume Makore} have in common that {Olive Ziricote Cedar(Leb) Wenge} do not have?




Mike Hill said:


> Does the chatoyance increase of decrease with the type of cut - i.e. rift, quarter, plain, live?


We did not see a significant impact of cut, with the following notes:
1) Softwoods are more chatoyant in their late growth rings (see example below). If your measurement area is on a QS surface you average correctly a number of early and late growth rings. But on FS surfaces you may end up with a measurement area that is mostly on late growth ring, thus reading a higher value, and vice versa.



2) Some cells (I ask wood anatomy experts to correct me if I am wrong) like medullary rays or flecks may have a different chatoyance; so this might make cut type relevant.
3) Figure may highlight chatoyance, and figure depends on cut.




Mike Hill said:


> Does it change due to where from the tree the wood comes from - near core - near bark?


No idea. We did some qualitative tests here:


Sapwood vs Heartwood – PZC Chatometry


We will do more.



Mike Hill said:


> Is it same with a transparent finish?


This is a good point: some finishes (shellac, BLO, ...?) are known to enhance it while some (in my experience flooring transparent finish) dampen it. No idea why...


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## phinds

The microscopic structure of latewood is different than that of earlywood in softwoods. The earlywood is generally much softer than the latewood. The extra density of the latewood is what makes its structure more chatoyant. Similarly, the microscopic structure of rays is different that that of non-ray areas. ALL of chatoyancy is due to differences in the microscopic structure of the different areas of wood and the fact that they cause light to be reflected differently at different angles because they themselves have different angles relative to the nominal surface of the wood at the macro level. I just don't get why everyone is having trouble with this concept. It seems very straightforward to me.


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## chatometry

Mike Hill said:


> If I look at the piece at 90 deg from the apparent surface plane - I see a lot of "figure". If I look at the piece at some angles of 45 deg and less, the figuring almost disappears.


Two players are missing: the direction of the light and the direction of the fibers. Make a sinple test, using your smartphone torchlight: look perpendicularly at the surface and light it with ~45° incidence angle. Then rotate the light around your optical axis and see what happens. For each point of the surface you should see max brightness when the light beam (projected on the surface) is roughly perpendicular to the fiber in that point. 



Mike Hill said:


> If in the cycle of the light if the surface of the wood is dark is NOT because there is no light reflecting off of if, but rather the light reflecting is not being reflected into our eyes, camera, meter, etc.


Maybe, or maybe because light gets absorbed into the fibers...? (I don't think so, however, because chatoyance is also very evident on split wood).


Mike Hill said:


> Can chatoyance exist with out "figure" - it appears so. But can certain figuring exist without chatoyance - I guess they can, but you might not be able to see it.


Fully agreed.



phinds said:


> The extra density of the latewood is what makes its structure more chatoyant.


Why? We have examples of non-chatoyant very dense woods (Buxus Sempervirens, Olive, ...).


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## phinds

chatometry said:


> Why? We have examples of non-chatoyant very dense woods (Buxus Sempervirens, Olive, ...).


Yes, that was an incomplete statement on my part. What I meant was that the heartwood density of THAT softwood makes it different than the sapwood of the same piece because of the different micro structure of that heartwood vs sapwood. I did not mean to imply that density always means chatoyancy, as it clearly does not.


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## vegas urban lumber

i have noticed a chatoyancy to the rather soft bland pallet wood from vietnam, that was decided in another thread was the plantation raised hybrid acacia






pallet wood nice contrast id help please


UPDATE: @vegas urban lumber --- Well, I'm no longer convinced that it's Acacia mangium, even though the end grain is an excellent match. The problem is that except for The Wood Database, which is completely at odds with other reports, Acacia mangium is a very hard, heavy wood used for heavy...



woodbarter.com


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## barry richardson

I have some (what i'm told by Mark Peet is some kind of fig) that has some incredible chatoyance. at least when a finish is applied... Desert ironwood is another. One thing I have noticed about DIW is the older wood, that has been dead a long time and darkened, loses a lot of it's chatoyance....


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## Karl_TN

chatometry said:


> Two players are missing: the direction of the light and the direction of the fibers. Make a sinple test, using your smartphone torchlight: look perpendicularly at the surface and light it with ~45° incidence angle. Then rotate the light around your optical axis and see what happens. For each point of the surface you should see max brightness when the light beam (projected on the surface) is roughly perpendicular to the fiber in that point.
> 
> 
> Maybe, or maybe because light gets absorbed into the fibers...? (I don't think so, however, because chatoyance is also very evident on split wood).
> 
> Fully agreed.
> 
> 
> Why? We have examples of non-chatoyant very dense woods (Buxus Sempervirens, Olive, ...).


@chatometry, Is there a pic or illustration of your chatoyance measuring setup? Better yet a video that shows it action?


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## chatometry

vegas urban lumber said:


> i have noticed a chatoyancy to the rather soft bland pallet wood from vietnam


Thank you. Was it a rough, finished or split surface?



barry richardson said:


> I have some (what i'm told by Mark Peet is some kind of fig) that has some incredible chatoyance. at least when a finish is applied...


Interesting - is it figured? What color is it (just to have a rough idea)?



barry richardson said:


> Desert ironwood is another. One thing I have noticed about DIW is the older wood, that has been dead a long time and darkened, loses a lot of it's chatoyance....


Good point. But... is it time since dearh, or is it time since sunlight and/or oxygen exposure?
All our tests are made on freshly sanded wood, but this page shows a comparison we made before and after quick (1 day) sunlight exposure on Purpleheart:


Sunlight exposure on field maple – PZC Chatometry



Anyway my experience tells me you are surely right on some woods, such as Padouk which eventually turns almost black. I don't know if ALL woods would eventually lose their visible chatoyance, and how long it would take.

@Karl_TN I will see what I can do.


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## barry richardson

> barry richardson said:
> Desert ironwood is another. One thing I have noticed about DIW is the older wood, that has been dead a long time and darkened, loses a lot of it's chatoyance....


Good point. But... is it time since dearh, or is it time since sunlight and/or oxygen exposure?
All our tests are made on freshly sanded wood, but this page shows a comparison we made before and after quick (1 day) sunlight exposure on Purpleheart:
Sunlight exposure – PZC Chatometry



It is the age of wood overall, even if you cut to the middle of an old piece, there is less chatoyance, it is a resinous wood, which eventually oxidizes all the way through...


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## barry richardson

Here is an example of the fig; the bottom part, this is a little darker color than the samples on Paul's site, this had some gray spalting patches in it. Im pretty sure its common fig, the kind you eat...

Reactions: EyeCandy! 3


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## Mike Hill

So, @chatometry addressed the density, so I can throw half of this post away.

@ chatomety - I know I'm asking a lot of questions, but by golly, I have them - it's what makes Lil Mikey so charming! Appreciate the time you and your colleagues put into this research and you answering questions. One of the failures of our society is that because we are so loosey-goosey, words have multiple meanings and are therefore at times rendered essentially useless. So this begs the first question for today.

First question this time - Is Reflection = Chatoyance a correct statement? If so, then why the difference in terminology? If not, then what is the difference? It seems to me what is being quantified is the delta in reflectance values off of something in or on wood. Am I in the ballpark?

Second question - Is chatoyance more pronounced in radial, tangential, or transverse planes of presentation?

Third question - since the wood we use is "dead" some for a longer time that others. And what we have left is basically dried up cell walls, have you tested any very freshly cut wood, before the cells have had a time to dry out?

Fourth question - Since when you cut and sand a piece of wood you essentially cut what used to be cells and pores. I suspect for the vast majority of a cut and sanded wood surface, if you magnified it, you would be seeing the insides of what used to be the cells. Take a look as some electron microscope images of wood. Sanding only smooths down the cut sides of what used to be the cell walls. Is the reflectance off the sanded edges of the dead cell walls or off the concave surface of the inner surface of the dead cells and pores?

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## vegas urban lumber

chatometry said:


> Thank you. Was it a rough, finished or split surface?
> 
> 
> Interesting - is it figured? What color is it (just to have a rough idea)?
> 
> 
> Good point. But... is it time since dearh, or is it time since sunlight and/or oxygen exposure?
> All our tests are made on freshly sanded wood, but this page shows a comparison we made before and after quick (1 day) sunlight exposure on Purpleheart:
> 
> 
> Sunlight exposure on field maple – PZC Chatometry
> 
> 
> 
> Anyway my experience tells me you are surely right on some woods, such as Padouk which eventually turns almost black. I don't know if ALL woods would eventually lose their visible chatoyance, and how long it would take.
> 
> @Karl_TN I will see what I can do.


slightly visible in some rough sawn boards just as they are on the pallets, more visible when sanded smooth as in the small table top i referred to having bought


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## barry richardson

Mike Hill said:


> So, @chatometry addressed the density, so I can throw half of this post away.
> 
> @ chatomety - I know I'm asking a lot of questions, but by golly, I have them - it's what makes Lil Mikey so charming! Appreciate the time you and your colleagues put into this research and you answering questions. One of the failures of our society is that because we are so loosey-goosey, words have multiple meanings and are therefore at times rendered essentially useless. So this begs the first question for today.
> 
> First question this time - Is Reflection = Chatoyance a correct statement? If so, then why the difference in terminology? If not, then what is the difference? It seems to me what is being quantified is the delta in reflectance values off of something in or on wood. Am I in the ballpark?
> 
> Second question - Is chatoyance more pronounced in radial, tangential, or transverse planes of presentation?
> 
> Third question - since the wood we use is "dead" some for a longer time that others. And what we have left is basically dried up cell walls, have you tested any very freshly cut wood, before the cells have had a time to dry out?
> 
> Fourth question - Since when you cut and sand a piece of wood you essentially cut what used to be cells and pores. I suspect for the vast majority of a cut and sanded wood surface, if you magnified it, you would be seeing the insides of what used to be the cells. Take a look as some electron microscope images of wood. Sanding only smooths down the cut sides of what used to be the cell walls. Is the reflectance off the sanded edges of the dead cell walls or off the concave surface of the inner surface of the dead cells and pores?


Food for thought

Reactions: Thank You! 1


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## chatometry

barry richardson said:


> It is the age of wood overall, even if you cut to the middle of an old piece, there is less chatoyance, it is a resinous wood, which eventually oxidizes all the way through


@Mr. Peet I read your post about those 100 years old samples from Philippines. Do any of those show visible chatoyance?



barry richardson said:


> Here is an example of the fig


Thank you. Nice piece.



vegas urban lumber said:


> visible in some rough sawn boards just as they are on the pallets, more visible when sanded smooth as in the small table top i referred to having bought


Thank you

@Karl_TN we are trying to have the method officially published. Then it will be available in full detail for everyone to replicate it.


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## chatometry

Mike Hill said:


> First question this time - Is Reflection = Chatoyance a correct statement


Technically I think it would be called "Anisotropic Reflectance", so yes, you are right. I've also seen it called "Anisotropic Gloss".



Mike Hill said:


> Second question - Is chatoyance more pronounced in radial, tangential, or transverse planes of presentation?


Not seen in transverse plane. That is, you might see some change in appearance, but it does not show the distinctive two-peaked chart (we only tested one sample).



Mike Hill said:


> have you tested any very freshly cut wood, before the cells have had a time to dry out?


No. We can arrange that.



Mike Hill said:


> Fourth question - Since when you cut and sand a piece of wood you essentially cut what used to be cells and pores. I suspect for the vast majority of a cut and sanded wood surface, if you magnified it, you would be seeing the insides of what used to be the cells. Take a look as some electron microscope images of wood. Sanding only smooths down the cut sides of what used to be the cell walls. Is the reflectance off the sanded edges of the dead cell walls or off the concave surface of the inner surface of the dead cells and pores?


I don't know.
But I can remark two things that are relevant:
1) brightness has a *sharp* peak when light is perpendicular to fiber direction 
2) chatoyance is higher in latewood for softwoods.

Your questions are very welcome - rather than questions and answers this is a proper positive discussion.


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## Mr. Peet

chatometry said:


> @Mr. Peet I read your post about those 100 years old samples from Philippines. Do any of those show visible chatoyance?
> 
> 
> Thank you. Nice piece.
> 
> 
> Thank you
> 
> @Karl_TN we are trying to have the method officially published. Then it will be available in full detail for everyone to replicate it.


Yes, many show chatoyance. Down side is I don't have time to get into them to share photos for a while, maybe November....


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## chatometry

Thanks
This tells us that at least some species retain some chatoyance after a century of aging (and oxygen exposure, as I guess they were not airtight packaged).

Reactions: Like 1


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## Mike Hill

True Paul, you are correct, I do not totally agree with your #50 post.

I am immensely aware that even a very finely sanded and polished wood surface is not a proverbial flat plane. Years ago, I was bothered by two things - the statement that sanding clogs the wood pores, and the way that wood stain acts - well, they also tied into myths within the bbq world. If you took culms of bamboo, rive them into equal halves longitudinally, turn them split sides out and hot glue them to something flat, you would end up with something resembling the surface of seasoned wood. That was an epiphany for Lil Mikey. Yet, it did not by itself explain lots of my questions at the time - but keep that vision in mind. Just postulations. Ok, tie that idea of the wood surface into a common tablespoon. Take a common shiny table spoon. View the back of the spoon - the convex part and what do you see? I see Lil Mikey's ugly face reflected back at me. Now turn the spoon around and view the concave side. Now I see Lil Mikey's face, but upside down and opposite handed. And since the bowl of a spoon is not part of a perfect sphere, the reflection is somewhat distorted making Lil Mikey more uglier. There has to be some magic involved since if you could hold the spoon close enough to your face the face would be right side up, but turn upside down as it moves out. Has to do with angles of reflectance and where that and the rays along the axis intersect. So then Lil Mikey wondered what would happen if instead of a sphere there was a shiny tube. The reflection on the outside of the tube is right side up no matter which direction the tube is positioned. But when Lil Mikey wanted to see what the inner concave surface of the tube would do - he was stymied - there ain't a lot of shiny half tubes around - so he dropped his inquiry until one day much later. One day he was sitting on th.......errr....the throne, when he happened to note that the toilet paper holder was shiny and the part that was recessed into the wall was tubular and concave. Eureka! So this being a construction company, we always have leftovers and knew I had noticed some out in the warehouse. So finished my duty and went to the warehouse to find out that the day before the leftovers had been given to Habitiat. So Lil Mikey went back into the little room, shut AND locked the door - didn't want anyone to think he was strange in any way. He sat on the floor, removed the toilet paper and looked at his reflection in the toilet paper holder body. If his face was perpendicular with the axis of the tube, then his face was upside down, but correct handed. Along the axis of the tube everything was "normal", but perpendicular it was upside down. Now all that could probably have been discovered with ray diagrams, but it was certainly more fun to sit on the floor of a bathroom to make the discovery! BTW the restroom has a faucet with a shiny chrome concave shape where at about a foot from it, the reflection turns upside down! For those who want to know - it doesn't take much to fascinate Lil Mikey1

So that is the reason for all the questions about light travels, angles of reflection and such. What they have recorded is a constant axis, and a constant angle between the light and the axis. The light does however, travel at differing angles from the longitudinal axis of the piece of wood. They found that brightness peaks when it is perpendicular to the fiber axis. That would make sense (I think) if the light is reflecting off of a concave tubular surface. If from a sperical surface as the light traverses it's course, all angle would be the same relative to the axis and should not change. Same with a perfectly flat surface.

"If you look at the surface of the Earth from far enough away it appears flat, but when you get up close enough you see that it has peaks and valleys." That is a partial explanation. True, our eyes are not capable of resolving detail from 100,000's or 1,000,000's miles away. It would be like comparing the resolution power of a 2mp camera image on a very low resolution monitor to the beautiful tonality and detail of an Ansel Adams contact film print taken with his 8x10 Deardorf. The earth is 1 AU from the sun or 93,000,000 miles (avg of the aphelion and the perihelion). Even though the sun is immense in comparison to the earth - at 93,000,000 miles it acts as a focused point of light with very little spread. So viewing the earth from miles and miles away with the sun at our back, there would be little if not any discernible shadows - therefore - little contrast to discern shapes by. Kinda like the proverbial overhead photo of camels on a sand dune lit by either a setting or rising sun. Shadows are thrown that allow you to ascertain the shape. If it was shot with the sun directly overhead (90 deg to surface) and the camera also at 90 deg to the surface all you would see would be the exterior outline of the camel from above and might not know it is a camel.

"Sanding gets rid of at least the biggest variations in the peaks and valleys in the wood which is why well sanded wood will show chatoyancy that rough wood won't." This is why my question of whether the reflectance is from the cut edge of the dead cell walls or from the concave inner surface of the cut open cell wall. In reality there could be a certain number of uncut dead cell walls (convex surfaces). The smaller the cell, possibly the greater number of uncut cells and more reflectance. If the brightest reflectance is due to fiber orientation, it should not make a difference that there is hills and valleys. Yes it does make a difference to bent wood fibers such as curl and quilt. I would suspect that sanding is and its effect on chatoyance is more mechanical. As cut the edges of the dead cell walls are pretty ragged and may cause at least part of the light exiting the empty cell to be diffused or specularized. By sanding those fuzzy cell edges are smoothed out and might not diffuse the light as much. It would be nice to have a scanning electron microscope in the back bedroom to use to answer just such a question. I would assume the way to know this is to observe how the light reacts when perpendicular to the fiber axis. But my brain isn't big enough to know the answer. Or is the light acting like a gem. Faceting of a gem has a lot to do with how much sparkle (reflection) and the color of the sparkle (refraction) it has. A facet is a cut and polished small flat face of a gem. There may be thousands on a certain gem cut pattern - each cut to a high degree of accuracy and precision. A ray of light passes through a facet and is reflected off the facets on the opposite side of the gem. If those facets are somehow aligned such that the light ray eventually pass back out that facet - then the facet sparkles. If the facets are somehow aligned such that the light bounces around and exits the gem through other facets then that facet is dark. I wonder if the inner walls of the cell act in that way? And yes, I have a faceting machine!

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## chatometry

@Mike Hill
This article explains some of the points we've been discussing about:






IET Digital Library: Estimating fibre orientation in spruce using lighting direction


Softwood is almost entirely composed of fibres and its physical properties depend on their orientation. A method is proposed to estimate the average fibre orientation at each pixel in the inspection image. In this study it is shown that finished wood has distinctive reflectance properties that...




digital-library.theiet.org






In general, chatoyance has been modeled for computer graphics purposes, so the effect is generally well known in qualitative terms: this article shows something:



[1511.04224] Procedural wood textures



(@phinds the fiber distortion we've been discussing is shown at page 16)


The reason behind chatoyance may be more complex than we know. One example is human hair (yes, they are chatoyant). This article shows that this is related to the "scaled" microgeometry of hair:









(PDF) Light scattering from human hair fibers


PDF | Light scattering from hair is normally simulated in computer graphics using Kajiya and Kay's classic phenomenological model. We have made new... | Find, read and cite all the research you need on ResearchGate




www.researchgate.net

Reactions: Informative 2


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## chatometry

Arn213 said:


> like to see the actual veneer photo of that ziricote and the end grain.


You were right. The piece I showed was not quartercut:




We have two samples which show the kind of figure you mentioned, and some localizeed areas have some chatoyance, which is well highlighted by adjacent non-chatoyant areas.









These are quartersawn:





From the numerical point of view the results are very low (<7) on these samples too, but this is because we are averaging over a large area most of which is non-chatoyant. We will need to localize the measurement on a specific spot to see what comes out.

Thanks for highlighting this property of QS Ziricote.

Reactions: Thank You! 1


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## Arn213

chatometry said:


> You were right. The piece I showed was not quartercut:
> View attachment 215068
> 
> We have two samples which show the kind of figure you mentioned, and some localizeed areas have some chatoyance, which is well highlighted by adjacent non-chatoyant areas.
> 
> View attachment 215070
> 
> View attachment 215071
> 
> These are quartersawn:
> 
> View attachment 215072
> 
> From the numerical point of view the results are very low (<7) on these samples too, but this is because we are averaging over a large area most of which is non-chatoyant. We will need to localize the measurement on a specific spot to see what comes out.
> 
> Thanks for highlighting this property of QS Ziricote.


Paolo thank you for checking on that and for verification. All ziricote are typically slab sawn cut. True quarter sawn ziricote is very hard to find.

Even your 2 samples shown aren’t true quarter sawn cut. You can can see how the growth rings how it deviates greatly in flat sawn direction even when you have 3-4 winter rings are close to being perpendicular. True quarter sawn ziricote will be filled with ray flakes up and down the board and will be 90 degrees. Those by my experience- visually to me anyways will have higher chatoyance factor.


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## phinds

Arn is, as usual, correct. I have had a LOT of zircote samples and not a one was true quartersawn. I think about 6 or 8 degrees off was the best I saw. BUT ... I once ran across an almost perfectly quartersawn plank in an exotic wood store.

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## Arn213

phinds said:


> Arn is, as usual, correct. I have had a LOT of zircote samples and not a one was true quartersawn. I think about 6 or 8 degrees off was the best I saw. BUT ... I once ran across an almost perfectly quartersawn plank in an exotic wood store.
> View attachment 215080


@phinds this is a great example- this is what I am talking about and that is as close you will get for a well quartered piece. You can even see all the ray flakes on the sapwood and notice there is no spiral grain pattern or cascading curve pattern. A clear horizontal band pattern will tend to be true quarter sawn with the added ray flakes for ziricote. That is an ideal sample for Paulo to measure.


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## chatometry

I will see if I can find something like that here.

With reference to the first gif I posted in message #85, this is the chatoyance map [white means chatoyance, black means no chatoyance]. I see black spots (flakes) of no chatoyance on a more chatoyant background, with the black spots covering a significant fraction of the surface.





We saw a similar behavior in other cases, such as this map from a Field Maple sample:





@Arn213 What is your experience with Bocote? We found it quite non-chatoyant, except for this sample which reaches almost 14 on the scale:




[Bocote sanded to 1500-grit]


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## phinds

I have not found bocote to be chatoyant in general but the occasional quartersawn piece will show a fair amount. Like this area of a mostly quartersawn plank


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## phinds

chatometry said:


> white means chatoyance, black means no chatoyance


That makes absolutely no sense to me. On a static picture there is NO chatoyancy. If you take oak, for example, the light/dark areas change places as you move the piece so BOTH areas have chatoyancy but only when the piece is moving.

Like this:


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## chatometry

phinds said:


> On a static picture there is NO chatoyancy


Why "static picture"? The grayscale pictures I am showing are maps showing where chatoyance is high and low, not wood pictures. For wood pictures I am showing animated gifs.



phinds said:


> If you take oak, for example, the light/dark areas change places as you move the piece so BOTH areas have chatoyancy but only when the piece is moving.


True for some species, like this European Beech sample (1500-grit):






Both areas have similar chatoyance.

(I don't have a good quartersawn oak example available, but I agree with you that in oak both areas are quite chatoyant. I also noticed it on bog oak)

Some other species show significant difference between the areas, like this London Plane sample (1500-grit):






We have preliminary data on Louro Faia which also shows much lower chatoyance on Flecks.

Does it make sense?


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## phinds

chatometry said:


> Why "static picture"? The grayscale pictures I am showing are maps showing where chatoyance is high and low


And my point is that as far as I can tell, in the oak in the link I provided as an example, the amount of chatoyancy does not vary significantly from the flakes to the non-flake areas, so a static picture showing chatoyancy would be all white which would not be helpful. What am I missing?

WAIT ... you show what I'm talking about yourself in your London plane example. It has fairly high chatoyancy in the non-flake areas AND the flake areas and yet your static pic shows no (or little) chatoyancy in the flakes.


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## Arn213

chatometry said:


> @Arn213 What is your experience with Bocote? We found it quite non-chatoyant, except for this sample which reaches almost 14 on the scale:





phinds said:


> I have not found bocote to be chatoyant in general but the occasional quartersawn piece will show a fair amount. Like this area of a mostly quartersawn plank


I am surprise it is even that high for bocote with what looks like an off quarter cut. Same experience as Paul and he is correct that you have to have a true quarter sawn piece with the ray flakes showing to get more chatoyant out of it (per his photo sample), but in general I don’t find it chatoyant at all. 

It would also help establish a perimeter if you delineate the test based on flat sawn versus true quarter sawn as it will effect your readings. The other condition is to show non figured versus non figured wood readings from the same species.

Reactions: Agree 1


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## 2feathers Creative Making

phinds said:


> And my point is that as far as I can tell, in the oak in the link I provided as an example, the amount of chatoyancy does not vary significantly from the flakes to the non-flake areas, so a static picture showing chatoyancy would be all white which would not be helpful. What am I missing?
> 
> WAIT ... you show what I'm talking about yourself in your London plane example. It has fairly high chatoyancy in the non-flake areas AND the flake areas and yet your static pic shows no (or little) chatoyancy in the flakes.


If you focus on the flake area, it never truly flashes like the other parts. True, the color changes but not intensely


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## phinds

2feathers Creative Making said:


> If you focus on the flake area, it never truly flashes like the other parts. True, the color changes but not intensely


The color changes TOTALLY from light to dark and back again. I believe that that is the DEFINTION of chatoyancy --- something that changes color or shininess depending on the angle at which you view it.


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## 2feathers Creative Making

phinds said:


> The color changes TOTALLY from light to dark and back again. I believe that that is the DEFINTION of chatoyancy --- something that changes color or shininess depending on the angle at which you view it.


I agree it appears to change. I also agree about the definition of chatoyance. They arent exactly measuring what we define as chatoyance but rather the changing reflectivity of the surfaces and the amount of reflection coupled with the change in the amount of reflection is going into these computations.

Reactions: Informative 1


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## chatometry

phinds said:


> so a static picture showing chatoyancy would be all white which would not be helpful.


Exactly...but it would tell you that every part is chatoyant, which is an information.



phinds said:


> WAIT ... you show what I'm talking about yourself in your London plane example. It has fairly high chatoyancy in the non-flake areas AND the flake areas and yet your static pic shows no (or little) chatoyancy in the flakes.


True. These maps show an intermediate parameter (not the PZC). We plan to re-plot them with the PZC, but it will take some time.
However, what @2feathers Creative Making says us true: the flecks do not change their brightness as intensely as the other areas. In general this makes sense: these are different cells cut in a different way, so one could expect a difference - at least, that's my thought.



Arn213 said:


> It would also help establish a perimeter if you delineate the test based on flat sawn versus true quarter sawn as it will effect your readings.


This is an important point. Let me explain my thought as it is now.
Most softwoods show higher chatoyance on latewood. So if you take a QS or RS section you cross a number of growth rings and you correctly average latewood and earlywood chatoyance. But if you take a FS section (of a very large tree) you may end up with a measurement area that is all on latewood or on all earlywood, and this can give significantly altered results. This Douglas Fir example shows the idea:







So on softwood I am happy with any cut, as long as my measurement includes at least one complete growth ring.

On hardwood we have flecks, which could make a perfect QS cut significantly different from any other cut (as you taught me). In fact flecks also appear in other cuts, but under a completely different look: they cover a lower area and they (possibly) show a different chatoyance.

So let's design together a test to clarify this point; my proposal is:
Find a wood blank at least 12*1.75*1.75 that is perfectly QS on one side.
The wood should be something fairly chatoyant with evident flecks. Maybe London Plane?
Cut the first 6" and slice it to make QS samples, and the other 6" to make FS samples.
Otherwise I can check if I already have some Sessile Oak (that's the everyday hardwood here).
I can get access to loads of Field Maple, but flecks are not always evident on that - am I right?

Paolo

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## phinds

chatometry said:


> So let's design together a test to clarify this point; my proposal is:
> Find a wood blank at least 12*1.75*1.75 that is perfectly QS on one side.
> The wood should be something fairly chatoyant with evident flecks. Maybe London Plane?
> Cut the first 6" and slice it to make QS samples, and the other 6" to make FS samples.
> Otherwise I can check if I already have some Sessile Oak (that's the everyday hardwood here).
> I can get access to loads of Field Maple, but flecks are not always evident on that - am I right?


I may have an American sycamore plank that has an area of strong flakes and an area of no, or very small, flakes. I'll look later today.


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## chatometry

Don't worry, I will look for something locally.
Any other ideas in addition to sycamore/plane and oak?


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## phinds

chatometry said:


> Don't worry, I will look for something locally.
> Any other ideas in addition to sycamore/plane and oak?


Sapele --- you can find quartersawn pieces w/ thousands of little bitty flakes, VERY chatoyant, and then others with no flakes.

Here's an example with flakes (but also, if I recall correctly, with a shellac finish):


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## vegas urban lumber

so i keep thinking about chatoyancy in stones such as tiger eye and others, maybe including even in opal. stone chatoyancy is often a matter of light refraction from microscopic parallel bands or spherules. the Wikipedia entry has a woodworking segment as well

https://en.wikipedia.org/wiki/Chatoyancy

does your work also include microscopic analyzation of the highest chatoyant areas to define the physical structure of the wood cells in that area?

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## chatometry

phinds said:


> Sapele


Thanks.



vegas urban lumber said:


> does your work also include microscopic analyzation of the highest chatoyant areas to define the physical structure of the wood cells in that area?


No - we are not equiped for such investigation. 
It would be really interesting, especially on chatoyant species like Sapele vs non-chatoyant like Olive.


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## vegas urban lumber

chatometry said:


> Thanks.
> 
> 
> No - we are not equiped for such investigation.
> It would be really interesting, especially on chatoyant species like Sapele vs non-chatoyant like Olive.


has anyone done such investigation? it seems to me that the root of your chatoyancy question lies in the physical microscopic properties of the wood. visual confirmation of chatoyancy seems highly subject and has many factors that might affect such, including sanding process, finish or lack there of, and potentially even things like moisture content and drying process both of which have high affect/effect on the wood

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## Mr. Peet

vegas urban lumber said:


> has anyone done such investigation? it seems to me that the root of your chatoyancy question lies in the physical microscopic properties of the wood. visual confirmation of chatoyancy seems highly subject and has many factors that might affect such, including sanding process, finish or lack there of, and potentially even things like moisture content and drying process both of which have high affect/effect on the wood


Sure IAWA has. International Association of Wood Anatomists.





__





IAWA website






iawa-website.org

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## Mike Hill

Sure IAWA has. International Association of Wood Anatomists.


Mr. Peet said:


> __
> 
> 
> 
> 
> 
> IAWA website
> 
> 
> 
> 
> 
> 
> iawa-website.org


So, what was the conclusion? The link was simply to their website where a load of information exists, but no discernable search capabilities. Maybe with a payment of a $318 subscription fee, there may be an index or search capability without having to individually search every single journal and bulletin published for decades.


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## Mr. Peet

Mike Hill said:


> Sure IAWA has. International Association of Wood Anatomists.
> 
> So, what was the conclusion? The link was simply to their website where a load of information exists, but no discernable search capabilities. Maybe with a payment of a $318 subscription fee, there may be an index or search capability without having to individually search every single journal and bulletin published for decades.


And that's how they get ya....

A simple answer is yes, some work has been done on it. The papers I had seen just a few to many years ago were beyond my organic chemistry talent. So, apologize for not being able to better direct.


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## chatometry

vegas urban lumber said:


> has anyone done such investigation


I agree with @Mr. Peet - someone surely did it. I do not know who and when, though.



vegas urban lumber said:


> visual confirmation of chatoyancy seems highly subject and has many factors that might affect such, including sanding process, finish or lack there of, and potentially even things like moisture content and drying process both of which have high affect/effect on the wood


100% agreed. We are trying to get rid of most of the variables, the goal being to identify typical values for the most commonly used species.

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## Gonzalodqa

I think the experiment is valid. What he is doing is assessing the presence of chatoyancy in a certain species, and the methodology since to be standardized under certain parameters (sanding method, finish, the data is collected using a specialized equipment). I think determining what causes the chatoyancy at anatomical level is not under the scope of the research. 
Further research on the subject can be suggested but there is only so much someone can study, and the best thing is to keep the focus in the research question that interest Paolo

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## chatometry

chatometry said:


> Find a wood blank at least 12*1.75*1.75 that is perfectly QS on one side.
> The wood should be something fairly chatoyant with evident flecks. Maybe London Plane?
> Cut the first 6" and slice it to make QS samples, and the other 6" to make FS samples.


I got this London Plane board. It has flecks, and I think I can cut both QS and FS samples. I am curious to see and compare the results...

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## chatometry

@phinds we had an open point on Iroko and sanding grit.

I got a sample from a board of known high chatoyance.

I sanded it to different grits and I had it measured at each step. Numerically, we found:

120-grit: PZC=11.8
180-grit: PZC=11.6
240-grit: PZC=11.2
320-grit: PZC=15.1
600-grit: PZC=13.8
800-grit: PZC=20.6
1500-grit: PZC=25.6

There is a clear trend of chatoyance increasing with grit, although in some cases increasing grit reduced chatoyance slightly. 
I think this is due to the fact that the 240-grit and 600-grit discs I used were brand new, while the other ones were worn; so maybe a worn 320-grit disc gives a smoother finish than a new 600-grit disc...? 
Anyway, let's take these two cases:




180-grit shows a little chatoyance (11.6) on a very chatoyant board (~25 when fine-sanded)




1500-grit shows very high chatoyance (25.6)

Now back to the sample you mentioned as being dull. I would think (option A) it came from a relatively low chatoyance board (such as the lowest we have, with PZC = 15.8 on average); whatever (low) chatoyance there was, it was dulled by the low-grit sanding and became invisible.
Otherwise (option B) it is really an unusually non-chatoyant board. I wouldn't be surprised.

More details (not much) here: 


Progressive grit sanding – PZC Chatometry

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## phinds

Great post. Very informative and interesting


chatometry said:


> ... maybe a worn 320-grit disc gives a smoother finish than a new 600-grit disc...?


Yes, that is possible. Depending on the type of material the grit is made of, new sandpaper can be noticeably more aggressive than an older piece of the same grit.


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## Mr. Peet

chatometry said:


> @phinds we had an open point on Iroko and sanding grit.
> 
> I got a sample from a board of known high chatoyance.
> 
> I sanded it to different grits and I had it measured at each step. Numerically, we found:
> 
> 120-grit: PZC=11.8
> 180-grit: PZC=11.6
> 240-grit: PZC=11.2
> 320-grit: PZC=15.1
> 600-grit: PZC=13.8
> 800-grit: PZC=20.6
> 1500-grit: PZC=25.6
> 
> There is a clear trend of chatoyance increasing with grit, although in some cases increasing grit reduced chatoyance slightly.
> I think this is due to the fact that the 240-grit and 600-grit discs I used were brand new, while the other ones were worn; so maybe a worn 320-grit disc gives a smoother finish than a new 600-grit disc...?
> Anyway, let's take these two cases:
> 
> View attachment 215432
> 180-grit shows a little chatoyance (11.6) on a very chatoyant board (~25 when fine-sanded)
> 
> View attachment 215433
> 1500-grit shows very high chatoyance (25.6)
> 
> Now back to the sample you mentioned as being dull. I would think (option A) it came from a relatively low chatoyance board (such as the lowest we have, with PZC = 15.8 on average); whatever (low) chatoyance there was, it was dulled by the low-grit sanding and became invisible.
> Otherwise (option B) it is really an unusually non-chatoyant board. I wouldn't be surprised.
> 
> More details (not much) here:
> 
> 
> Progressive grit sanding – PZC Chatometry


Polishing by sanding can for sure increase intensity. It can also caramelize and crystallize depending on heat created. This can alter results as well.

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## chatometry

Thanks. What kind of sanding method would you expect to cause caramelization?
I'd be thinking of high speed stuff, like angle grinder sanding discs. Would a belt sander also cause this effect?
We are now using a random orbit sander.


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## Mr. Peet

chatometry said:


> Thanks. What kind of sanding method would you expect to cause caramelization?
> I'd be thinking of high speed stuff, like angle grinder sanding discs. Would a belt sander also cause this effect?
> We are now using a random orbit sander.


Yes, belt sanders are known for such. The pressure being held against the wood also plays part. The wood structure comes into play as well, ring porous versus other. And most important, wood temperature, how hot the wood gets during the process.

There are other causes as well. For example, many maple species harvested in the spring will have higher sucrose levels in the wood than those harvested in winter. The higher the level, the easier to scorch, thus the need for really sharp tooling when dealing with such.

An orbital sander with dust removal, like Festol, do a great job.

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## chatometry

Thanks, I had no idea about this. Is this also related to purpleheart burning very easily when routed?


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## phinds

chatometry said:


> Thanks, I had no idea about this. Is this also related to purpleheart burning very easily when routed?


Purpleheart is a special case. It has resins that are particuarly sensitive to temperature. Take a look at my purpleheart page for a discussion.

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## phinds

I should add that while I don't know about carmalization, I know from extensive personal experience that random orbital sanding with regular pads and a regular ROS (not Festool) of the end grain will, on some woods, cause extensive micro fractures in the wood which are easy to see at 10X. Never paid any attention to what it does to face grain.


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## Nature Man

It would seem to me that for a fair comparison between species, the starting point on sanding should include new sandpaper in every case. Sandpaper is cheap, and for the sake of a scientific research project, every single entering argument should be controlled. Chuck

Reactions: Agree 1


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## phinds

Nature Man said:


> It would seem to me that for a fair comparison between species, the starting point on sanding should include new sandpaper in every case. Sandpaper is cheap, and for the sake of a scientific research project, every single entering argument should be controlled. Chuck


I disagree. Only the last couple of grits need to be new. All the previous, lower, grits can be old and you'll still get the same result.


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## Mr. Peet

phinds said:


> I disagree. Only the last couple of grits need to be new. All the previous, lower, grits can be old and you'll still get the same result.


I follow your point Paul, going from A to B. You are interested in comparing the two, not the progress between. Think Chuck was also hinting the comparison of all points between to some depth. A gauging of tenacity, resistance, density, and structural influence on results. Too much for me, but someone might try.

Reactions: Agree 1


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## phinds

Mr. Peet said:


> I follow your point Paul, going from A to B. You are interested in comparing the two, not the progress between. Think Chuck was also hinting the comparison of all points between to some depth. A gauging of tenacity, resistance, density, and structural influence on results. Too much for me, but someone might try.


Ah ... right, if you're going to check chatoyancy after every grit, as Paolo did on one sample, then it probably is a good idea to not let any of the grits get worn down much.

Reactions: Agree 1


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## chatometry

phinds said:


> Take a look at my purpleheart page for a discussion.


Interesting stuff! When cooking, did you also notice an effect on chatoyance?


phinds said:


> cause extensive micro fractures in the wood which are easy to see at 10X.


What grit would this be caused by? Fine, coarse, or both? Thanks for sharing your end-grain sanding sequence (on your website).

I will see if I can have the progressive grit vs chatoyance test repeated with a full set of brand new discs...


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## phinds

chatometry said:


> Interesting stuff! When cooking, did you also notice an effect on chatoyance?


I've never paid attention to chatoyancy in purpleheart because I haven't noticed it to HAVE any.


chatometry said:


> What grit would this be caused by? Fine, coarse, or both? Thanks for sharing your end-grain sanding sequence (on your website).


Happens w/ the fine grit. It's the heat that does it and the fine grits heat up the wood more than the coarse grits. I wouldn't worry about it w/ the face grain though. Now, the carmalization that Mark mentioned might be an issue. That's something I had not even heard of before.


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## chatometry

Thank you @phinds. 
On some of our purpleheart samples we found some chatoyance; this is the only figured one I could find:






Mr. Peet said:


> It can also caramelize and crystallize depending on heat created.


Is this something easy to detect? Or is it a subtle alteration which requires a dedicated inspection to detect?


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## phinds

chatometry said:


> Thank you @phinds.
> On some of our purpleheart samples we found some chatoyance; this is the only figured one I could find:


Oh, I wasn't suggesting it never has any, I just haven't ever experienced it that I can recall.


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## Mr. Peet

chatometry said:


> Thank you @phinds.
> On some of our purpleheart samples we found some chatoyance; this is the only figured one I could find:
> View attachment 215501
> 
> 
> Is this something easy to detect? Or is it a subtle alteration which requires a dedicated inspection to detect?


Caramelization often is just tagged as 'scorch' or 'burnt' by most wood workers. When it is subtle, it often is overlooked or taken as a hue / color. Happens more often as said, when polishing and working finer grits.


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## chatometry

@phinds
@Mr. Peet
@Mike Hill
@Arn213
@2feathers Creative Making

We ran the planned Quartersawn vs Flatsawn test on London Plane, with this sample layout:




Quartersawn surface shows the distinctive flecks (medullary rays) which provide contrast making chatoyance much more evident.
From numbers, chatoyance appears to be slightly lower on Rift/Flat surfaces (11.3 on average of 18 measurements) rather than Quartersawn surfaces (12.1 on average of 12 measurements). Below two examples:




Sample 2 - PZC 12.6




Sample 10 - PZC 10.4

This was further investigated by plotting PZC on the surface.
It appears that the flecks show higher chatoyance than the surrounding areas (PZC ≈ 15-20 vs PZC ≈ 5-15):





...but this only happens when they are cut flat (i.e. QS). When they are cut perpendicularly (i.e. FS) they appear less chatoyant (PZC ≈ 5-10), while the surrounding areas stay roughly the same (PZC ≈ 10-15):




This may possibly explain why the QS surface shows higher PZC.

Interestingly, another set of QS samples from another source shows much higher PZC on main fibers ( ≈ 15-30) rather than medullary rays ( ≈ 10-15):








I'm afraid this posts generates more questions than answers... However I think that the presence of flecks causes additional complexity; we should do the same comparative tests on some wood with chatoyance and without flecks...

Reactions: Like 1 | Informative 3


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## phinds

Great post. Thanks. Did you get the veneer yet?


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## chatometry

phinds said:


> Great post. Thanks. Did you get the veneer yet?


Not yet... The last tracking update says they were in NY on August 27


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## chatometry

Here's some beauty from Hawaii...

















With PZC above 24 on average (8 different logs), this is now the most chatoyant of the 57 species we tested so far! (@Arn213 ...)

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## Arn213

chatometry said:


> Here's some beauty from Hawaii...
> 
> View attachment 216103
> View attachment 216104
> View attachment 216105
> View attachment 216106
> View attachment 216107
> 
> With PZC above 24 on average (8 different logs), this is now the most chatoyant of the 57 species we tested so far! (@Arn213 ...)


Like I was saying all along going back to post #2 to all you non believers and skeptics thought I was talking smack. 

Just don’t repeat your findings to the stoopid Islander because he will add that to his arsenal when he preaches that he wants all the “Hawaiian liquid gold” to be brought back in it’s rightful birthplace. Aloha

Reactions: Agree 1 | +Karma 1


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## chatometry

I wanted to share a peculiar example from a few thousands years ago (quartersawn bog oak):

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## phinds

Nice.


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## vegas urban lumber

chatometry said:


> I wanted to share a peculiar example from a few thousands years ago (quartersawn bog oak):
> 
> View attachment 216281


reflective or chatoyant quality regardless of wood color, points to cell structure


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## phinds

vegas urban lumber said:


> reflective or chatoyant quality regardless of wood color, points to cell structure


And this is an interesting demonstration of how hundreds of years (Paolo says thousands and it could be) does not degrade the cell structure in bog oak. I knew that already from end grain analysis but it's still interesting to see another way of confirming that.

Reactions: Informative 1


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## chatometry

To be fair I don't know... I was told 5000-10000 years, but I have no knowledge to confim that. What happens to bog oak? Why does it turn black?


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## vegas urban lumber

chatometry said:


> To be fair I don't know... I was told 5000-10000 years, but I have no knowledge to confim that. What happens to bog oak? Why does it turn black?


mineral staining?


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## phinds

chatometry said:


> What happens to bog oak? Why does it turn black?





vegas urban lumber said:


> mineral staining?



Sort of, is my understanding. It's something about the composition of the peat in the peat bogs reacting w/ the tannin in the oak. Sinker logs of oak can be in lakes/rivers for decades or even 100+ years and they don't turn black. I'm stating that based on an old memory from a potentially faulty memory. Oak that sinks in moist areas that are not peat bogs still turn dark but not black like peat bog oak.

Reactions: Agree 1


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## Arn213

One species from New Zealand called Ancient Kauri that has been preserved in bogs or swamps also do not turn black. That definitely is a species you want to test as the ones with “white bait pattern” is incredibly radiant and has high chatoyance.

The sinker mahogany salvaged from Belize as well tend to keep their color, but they tend to be heavier, richer in color and more chatoyant by my experience.

Sinker redwood can go either way- they can range from orange heartwood to marbled chocolate to charcoal. I have several billets which one was ocean salvaged that is marbled chocolate and charcoal in color and I have some non figured sinker redwood salvaged from the Elk River in Oregon also has this marbled coloration going on. Photo’s below:









Paolo, it would be interesting if you include sinker salvaged species on your study as to me based on my experience and probably has to do with the naturally curing/preservation under water that there is that extra chatoyance to these species when unearthed and dried properly. When you re-saw it, there is this extra “shimmer/glow” that you see more present compared to non sinker species.

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## phinds

Arn213 said:


> Paolo, it would be interesting if you include sinker salvaged species on your study ...


I agree. Can you provide some for him? Can others here? I don't have any.


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## Arn213

phinds said:


> I agree. Can you provide some for him? Can others here? I don't have any.


Paul, I have messaged him awhile back about samples as he requested some from me- he knows my situation. Unfortunately I don’t have any of those woods I mentioned accessible to me at the moment. Hoping someone here can be of help.

We have a lot of domestic woods that did not make it on the way to the mill via water way from centuries ago and only now we have independent companies salvaging them from the bottom like sinker cypress, redwoods, sitka spruce, pine, Douglas fir maple, birdseye maple, flame red birch, walnut, oak, elm, cherry to name a few.

I had several sets of these but it is now completely gone to a better home to one of the members here. This was one of the nicest sounding/resonant and bar none the highest chatoyance I have seen on old growth sitka spruce! This was ocean salvaged from Alaska and had the nicest revealing ray flakes thought out the surface. I have had regular sitka spruce soundboards in my stock, but never had this shimmer and sparkle on the surface….……this just had that natural aged character patina that you see on vintage instruments.

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## vegas urban lumber

Arn213 said:


> One species from New Zealand called Ancient Kauri that has been preserved in bogs or swamps also do not turn black. That definitely is a species you want to test as the ones with “white bait pattern” is incredibly radiant and has high chatoyance.
> 
> The sinker mahogany salvaged from Belize as well tend to keep their color, but they tend to be heavier, richer in color and more chatoyant by my experience.
> 
> Sinker redwood can go either way- they can range from orange heartwood to marbled chocolate to charcoal. I have several billets which one was ocean salvaged that is marbled chocolate and charcoal in color and I have some non figured sinker redwood salvaged from the Elk River in Oregon also has this marbled coloration going on. Photo’s below:
> 
> View attachment 216327
> 
> View attachment 216328
> 
> Paolo, it would be interesting if you include sinker salvaged species on your study as to me based on my experience and probably has to do with the naturally curing/preservation under water that there is that extra chatoyance to these species when unearthed and dried properly. When you re-saw it, there is this extra “shimmer/glow” that you see more present compared to non sinker species.


in those cases then silica content may play a roll, would be interesting to know if non sinker species with higher silica content are in fact highly chatoyant


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## chatometry

Thanks everyone for the info and suggestions.
@Arn213 this is interesting.
Do you know of companies or people who have access to such sinker logs? The issue is not finding one piece, but one piece from each of many different logs.
@Paul Veerkamp here is helping us, and I want to thank him. Also a gentleman from Louisiana is willing to ship sinker cypress samples. 
I will search for companies specialized on this and see what we can get.

By "sinker logs", how many years are we talking about? Decades, centuries, or more?

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## phinds

Paolo, sinkers are generally decades to many decades old since it's been a while since there were frequent mass log-rafts floating down to the mills. I know there are companies that specialize it sinker logs, particularly cypress, but I don't have a link for you.


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## chatometry

Thank you

On a different point, here are the first results on samples kindly provided by forum members:




Cerejeira from @Gonzalodqa - PZC=15.6 - just above data from other 4 sources we have (11.7÷15.3)




Eucalyptus from @Gonzalodqa - PZC=16.3 - within the range we found from 6 other sources (11.1÷16.5)

@phinds your samples are next in line :)

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## Paul Veerkamp

chatometry said:


> Thanks everyone for the info and suggestions.
> @Arn213 this is interesting.
> Do you know of companies or people who have access to such sinker logs? The issue is not finding one piece, but one piece from each of many different logs.
> @Paul Veerkamp here is helping us, and I want to thank him. Also a gentleman from Louisiana is willing to ship sinker cypress samples.
> I will search for companies specialized on this and see what we can get.
> 
> By "sinker logs", how many years are we talking about? Decades, centuries, or more?


You should be getting those samples any day. Got another log today. You can see the root ball just under the water.

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## chatometry

These Etimoe samples, from 2 different flitches, were kindly provided by @phinds:




Flatsawn - PZC = 27.8
Above the range we found from 5 other sources (17.6÷26.8)




Quartersawn - PZC = 25.3 
Within the range we found from 5 other sources (17.6÷26.8)
Nice wood!



Paul Veerkamp said:


> Got another log today.


Nice picture... Looks like a tough job!

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## Arn213

chatometry said:


> Thanks everyone for the info and suggestions.
> @Arn213 this is interesting.
> Do you know of companies or people who have access to such sinker logs? The issue is not finding one piece, but one piece from each of many different logs.
> @Paul Veerkamp here is helping us, and I want to thank him. Also a gentleman from Louisiana is willing to ship sinker cypress samples.
> I will search for companies specialized on this and see what we can get.
> 
> By "sinker logs", how many years are we talking about? Decades, centuries, or more?


Paolo I sent you a pm with the info. They should have logs numbered so you can get sample from each piece. Hopefully they can accommodate you.

FYI- sinker woods in general could be centuries or over many centuries old under water that didn’t make it to the mill via waterway. They are rather expensive due to labor, time and added special equipment. Musical woods tend to cost more not just because of what I mentioned above because they have to be axe split, perfectly quarter sawn (other required criteria’s for sonic and mechanical attributes required for musical instruments) as well properly dried and seasoned.


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## chatometry

Thank you. Very interesting.

Do you also have experience with wood for violins? Have violin backs always been curly maple, or are there successful variants, either with plain maple or other wood species?


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## Mike Hill

I'm gonna sit back, get an americano with extra shots and a bowl of popcorn and await and enjoy this reponse! It might not be short! Hee Hee!

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## Arn213

^Yes. Different criteria and requirements for bowed instruments. Consider the source from the great masters (Amati, Stradivari, Guarneri and Cremona region)- high altitude, slow growing and cold weather for the Alpine spruce (sound board) and Euro maple (back/ribs/neck/bridge) with tight annular growth rings- has to be true quarter sawn. The spruce sound board and maple parts are axe cut/split in quarter log form. Ebony for the fingerboard, pegs and tailpiece. Kiln dried wood is not accepted because it collapses and changes the anatomical structure and acoustical properties- so “air drying” is the well accepted way of naturally drying and seasoning the woods as it keeps the structure intact.

Violin backs can be book-matched from a billet (usually they are wedged shape where it is thicker in the middle and tapers down at the perimeter) or be one piece. There are examples that has been “slip matched” (backs). Most have degrees of figuring, but plain/non-figured back/ribs and neck does exist. I have seen some violins with birdseye maple.

Then of course there is the violin bow which is either pernambuco/brazilwood- same tree, but the name category determines that depending of the “velocity of sound” via numeral classification (higher number versus lower number) and mature wood vs younger wood. Elasticity = (velocity)2 x density. The denser portion and mature wood will have a higher reading if you use a Lucchi meter and as you move away from the center of the log (east to west or vice versa) to the outside of the log, you will have slightly lower reading. So a reading of 5000 to 6000 plus will be classified as Pernambuco and readings about 4200-4900 will fall under Brazilwood. Ofcourse the number classification affects price.


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## Arn213

Mike Hill said:


> I'm gonna sit back, get an americano with extra shots and a bowl of popcorn and await and enjoy this reponse! It might not be short! Hee Hee!


So @Mike Hill- you went from black coffee to an Americano? I’ll take some Tiramisu with mine and while you have a “stab at this” as I know you are itching. I am waiting for you to take us “down the rabbit hole”. Lol.

Reactions: Funny 1


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## barry richardson

I may have missed this, but have you tested African Mahogany? I was in a pub the other day and noticed the tables were quarter sawn AM with clear coat on them, they had an amazing 3D look....


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## Mike Hill

Now, with possession of a caffeine buzz and after digging popcorn out from between my teeth with a toothpick I'll add to what Arn wrote while exuding pride of my alma mater (Texas A&M). All Arn said plus the following. While Lil Mikey was matriculating, a biochemistry prof with a passion for violins started serious study of why Strads sounded so beautiful. He noted that many descriptions included that the best Strads mimicked attributes of the human female voice. This has been verified by later studies. The findings that this prof came up with 40 years ago were corroborated just last month (Aug 2021). Many theories abound that include soil composition of where the trees were growing, to methods and length diverting and during the wood, to secret varnish recipes, to the wood soaking in water for quite some time, etc. All but the finish recipe were viable. There were not all that many types of finishes 200+ years ago. He claimed to not being able to ascertain discernable differences in sound from different apparent finishes. After a few years of study, he was able to study some actual wood of a Guarinius cello. He found what he expected - "the salt of gems" or rather the surface saturated with fine chemical crystals. He had previously experimented with with things such as powdered insect wings or powdered shrimp shells as wood fillers. He suspected that other substances were used. Recently those substances have been identified - borax, zinc, copper, alum, and lime water. But why? Some secret tone generating concoction? Not likely! Apparently, there was trouble with wood-eating worms and other wood detriments at the time. Apparently it was not uncommon for woodworker of the time to slather wood with concoctions (flurries of chemicals the alchemists called the salt of gems) to try to keep the worms and mold at bay and preserve the wood. The chemicals were found not only on the exterior surface but all over AND also inside the wood indicating soaking. Whoda thunk that not only fine craftsmanship but chemicals combine to produce the fine sound of instruments from the Golden Era. Of course this has nothing to do with chatoyance, but I like thinking about it. Beat that you tea-sips! It's a Texas thang!

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## Mike Hill

Arn213 said:


> So @Mike Hill- you went from black coffee to an Americano? I’ll take some Tiramisu with mine and while you have a “stab at this” as I know you are itching. I am waiting for you to take us “down the rabbit hole”. Lol.


Now keep in mind that Americanos with extra shots are just fancy black coffee with additional black coffee and caffeine added - and that is a wonderful thing!! Tiramisu would be a wonderful side dish, but I have already had a Napolean and a dark chocolate eclair from a patisserie that happens to be too close to where I live - it's a dangerous place for Lil Mikey to drive past!!!!!!!! He is not always successful at driving past.

Reactions: Funny 3


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## Arn213

Poor Paolo @chatometry- you have to be careful when you ask that “wide open” of a question as you stated on post #150 as you will get more answers than you bargained for. When you ask about violin woods that subject will always gets redirected towards Stradivari which could lead to controversy and endless debate as there are many hypothesis made in what makes his violins historically prized and significant to the music world. That subject alone I would imagine would greatly deviate from your research and I am not quite sure to what perspective and angle you are looking at where “you can connect the dots” and where this subject becomes relevant to your research.

Although this might be a significant importance. Does method of drying effect chatoyance? Kiln drying versus thermal roasting method versus air drying method?

To bring out the most chatoyance- does sanding (even at a higher grit, sanding wet to thousand grits) net higher results of chatoyance compare to hand planing with an iron blade. I have seen highly polished mirror, surfaced finish on woods with hand planes and have had equal results using Japanese hand planes with blue steel, white steel as well as with Swedish steel planer blades. Food for thought.

As for you @Mike Hill- don’t know where to put you or what to do with you. Lol. You are always full of sly humor, wit and sound information. But, the coffee and the popcorn I am not digging that much kind of weird combination- but hey if it was caramel popcorn I might dig that……..everything you said I can also confirm and just will add a couple of bits of information. Test findings on the Stradivari’s multiple instrument shavings including a Guarneri that there are “chemical present” deeply infused into the woods that is not present on modern day violins- it is theorized that the foresters put chemicals in the woods in order to ward off worms and fungus growth. Otherwise they would not be able to sell the wood. “Copper, aluminum, calcium and other elements were found”. The other findings is “1/3rd of the wood component hemicellulose had decomposed”. “Wood fiber detachment was found” due to vibrations from playing over time. They did not test for the varnish on this specifically.

So why is there such an obsession you ask for centuries and centuries to replicate the geometry, methodology, construction, varnish formula, seek the correct aged and region woods from Stradivari’s violin (or an Amati or a Guarneri) and the overall tonal sound? They want to replicate and preserve the Stradivari sound because in the test they found out from the heated wood shavings from the violins that there is an “extra peak of oxidation, which implies detachment between wood fibers”. That results from playing the instruments over time and theorize the “detachment” is due to “vibrations”. So due to the continuing decomposition that they believe that in 100 years or so they will ”lose their acoustics”!!!!! Realistically speaking centuries and centuries of violin building, I highly doubt that someone will “break the code”. They always look the part, but never play the part. They have done blind fold test of professional violinist where they will play modern violins and a Stradivari’s- guess what they always picked? A modern violin. One of the biggest ingredient in the equation that really is missing is Stradivari himself to properly replicate that sonic footprint- we all know that is not happening and his name is not Lazarus.

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## chatometry

Thanks @Arn213 and @Mike Hill
Ah ah ah to be fair I did't want to enter the endless labyrinth of violin woods, shape, finishes, etc.
Let me explain:
I never built a guitar, but a few years ago I built a violin, and I am under this impression:
Guitars can be made of loads of different woods, it's the luthier's or customer's choice.
But violins have a strictly defined part list.
Every part and detail of a violin aims at technical perfection [not aesthetic] (except maybe for the carved neck), and when I look at a violin I see a piece of engineering rather than a nice looking instrument. No fancy colours, no exotic woods, just the right stuff.
I want to remind that the "figure" in curly maple reveals a wavy fiber distribution, as opposed to a straight fiber distribution... This means that the "figure" highlights a different mechanical behavior.
Now: could it be that curly maple was selected* instead of plain maple because of better tonal properties? Or would it be just for aesthetic purposes? 

*:... after trial and error carried out by our ancestors

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## chatometry

barry richardson said:


> I may have missed this, but have you tested African Mahogany?


Do you mean Khaya spp.?
If so, yes (samples from only 6 different logs though), and with average PZC = 23 it is the third most chatoyant wood we found so far (out of 66 species).

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## phinds

chatometry said:


> I want to remind that the "figure" in curly maple reveals a wavy fiber distribution, as opposed to a straight fiber distribution...


Just to be clear, you are not talking about grain, right? I don't see any wavy fiber on this piece but maybe it's there. What's NOT there is wavy grain.





Here's wavy grain (which sometimes results in curly figure, sometimes doesn't) without curly figure




and here's wavy grain WITH curly figure:




So if by "fiber" you mean grain lines, then no, it doesn't always cause curly figure.

All this is from http://www.hobbithouseinc.com/personal/woodpics/_wavygrain.htm

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## Mike Hill

chatometry said:


> Thanks @Arn213 and @Mike Hill
> Ah ah ah to be fair I did't want to enter the endless labyrinth of violin woods, shape, finishes, etc.
> Let me explain:
> I never built a guitar, but a few years ago I built a violin, and I am under this impression:
> Guitars can be made of loads of different woods, it's the luthier's or customer's choice.
> But violins have a strictly defined part list.
> Every part and detail of a violin aims at technical perfection [not aesthetic] (except maybe for the carved neck), and when I look at a violin I see a piece of engineering rather than a nice looking instrument. No fancy colours, no exotic woods, just the right stuff.
> I want to remind that the "figure" in curly maple reveals a wavy fiber distribution, as opposed to a straight fiber distribution... This means that the "figure" highlights a different mechanical behavior.
> Now: could it be that curly maple was selected* instead of plain maple because of better tonal properties? Or would it be just for aesthetic purposes?
> 
> *:... after trial and error carried out by our ancestors


After stroking my white chin stubble a little - I would have to ascribe the differences in guitar and violin construction to the end user. IN GENERAL - guitar music is mass produced music made for a beat and to dance to, while violin music, to me, is listening music. The end user of guitar music and instruments seem to have a greater need to be different or extreme rather than good as compared to a "standard". Violins and violin music seem to be generally compared to a standard. Do I dare say that there may be a tad more reverence in conjunction with violins rather than in guitars? I've seen a few "different" violins, but they don't seem to have caught on as powerfully as the "different" guitars.

In regards to the studies where the sound of modern violins were chosen over the sound of Cremonian instruments, it is interesting what the biochemistry prof says about them. It is interesting that not always was the new picked over old, but 60%. Additional studies indicate that in side by side comparisions, the more modern violins are also louder and louder was usually selected. 

I own a bible that has a 400 year birthday this year. That puts it's publishing 23 years before the Strad dude was born - at the very end of the Renaissance Era. The Middle Ages had gone the way of the dinosaurs as well as most of Middle English (thankfully no more Chaucer to be produced). This was the era of Early Modern English. Easier to read than Middle English, but more difficult than Lil Mikey likes. Lil Mikey greatly prefers reading the english of more modern tomes. The ideas and definitions are the same, but put out there on paper differently. Why my preference? Because that is what I am used to! If I lived in 1621, I might prefer the Early Modern English. I liken the violin preference to that - if all you've known is the sound of modern violins and think that is perfection, then you will likely pick that over the old Strads. Myself, I prefer to cast bamboo fly rods. I like the way they feel over the modern carbon and resin ones. Others don't, and even Lil Mikey will occassionally use a modern "helicopter rotor technology" rod. The prof said something like this. Strad produced about 1200 violins that he sold to the wealthiest of the wealthy. About 600 still exist. Of the 600 extant, not all are great sounding instruments - some are duds. He postulated that the Cremonian instruments used for the comparison were not the cream of the crop. I suspect the people who write stories in the modern press often offer extrapolations of the results/conclusions that are ------ hyped.


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## barry richardson

chatometry said:


> Do you mean Khaya spp.?
> If so, yes (samples from only 6 different logs though), and with average PZC = 23 it is the third most chatoyant wood we found so far (out of 66 species).


Yes, that's it...


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## Mike Hill

Arn213 said:


> But, the coffee and the popcorn I am not digging that much kind of weird combination-


Do I dare say that a NYC'er might not understand "the redneck way?"


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## Arn213

chatometry said:


> Thanks @Arn213 and @Mike Hill
> Ah ah ah to be fair I did't want to enter the endless labyrinth of violin woods, shape, finishes, etc.
> Let me explain:
> I never built a guitar, but a few years ago I built a violin, and I am under this impression:
> Guitars can be made of loads of different woods, it's the luthier's or customer's choice.
> But violins have a strictly defined part list.
> Every part and detail of a violin aims at technical perfection [not aesthetic] (except maybe for the carved neck), and when I look at a violin I see a piece of engineering rather than a nice looking instrument. No fancy colours, no exotic woods, just the right stuff.
> I want to remind that the "figure" in curly maple reveals a wavy fiber distribution, as opposed to a straight fiber distribution... This means that the "figure" highlights a different mechanical behavior.
> Now: could it be that curly maple was selected* instead of plain maple because of better tonal properties? Or would it be just for aesthetic purposes?
> 
> *:... after trial and error carried out by our ancestors


When you built that violin you gained respect, knowledge and appreciation in how it was more than a beautiful piece of instrument that it’s main function was a “tool” for making music. You would have to build “guitars” in order for you to also change your misconception that a guitar is not a “fine tweaked or a well engineered musical instrument”. Yes, the violin is at the highest level when it comes to a musical instrument as it has been documented in history, recordings, performance and what have you.

A musical instrument that takes “cues” to violin design and construction is an “archtop” guitar. Coincidentally, the most notable and influential archtop builders of our time were American-Italian descent. John D’Angelico, James D’Aquisto and Robert Benedetto. Archtop builders adopted “violin” making techniques/principles as well as materials employed- you can see the resemblance from the photo’s below. So they followed the same sets of criteria and strict guidelines that was set forth by violin makers including selecting the proper wood with keeping in mind that an archtop required a much larger foot print & a different geometry in order to draw out the volume output required (but this has evolved over the years out of necessity and an acoustic archtop nowadays have been fitted with a neck pickup along with an amplifier in order to be able to get controlled and more volume out of the instrument).


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## Arn213

chatometry said:


> I want to remind that the "figure" in curly maple reveals a wavy fiber distribution, as opposed to a straight fiber distribution... This means that the "figure" highlights a different mechanical behavior.
> Now: could it be that curly maple was selected* instead of plain maple because of better tonal properties? Or would it be just for aesthetic purposes?
> 
> *:... after trial and error carried out by our ancestors


You need to be clear on this in regards to figure and grain. Better qualities outside of mechanical usually defines cosmetic and aesthetic when it comes to figured woods. Figured woods tend to be less dimensionally stable compared to non figured woods. Mechanical properties is important criteria, however sonic properties and velocity of sound is also an utmost importance when selecting material in making an instrument.

You have to find me a study that proves that “curly maple” or “figuring” makes better tonal properties- otherwise it is just aesthetic and cosmetic feature as other variables in making a fine sounding instrument and the biggest factor in that that equation to me is the skill and experience of the luthier. Without a luthiers hands, ears and direction it is just a pile of woods with some tap tone response.


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## chatometry

phinds said:


> Just to be clear, you are not talking about grain, right?


I think so. I am referring to the direction of wood fibers, but I don't know its technical name.
That maple picture was exactly what I had in mind to see the effect.
Why do you say that the side grain is not wavy? I would say that there is a slight waviness... but maybe I am wrong.
The anisotropic reflection gives two very sharp brightness peaks, so it takes just a little waviness of the grain to have a curly figure.

I have a similar piece (and a much worse picture):




Some photoshop reveals grain slightly better. It is just slightly wavy...




Going to the second photo you posted, I guess it's just because it is a non-chatoyant wood, or a finish or sanding grit which does not reveal chatoyance... I don't know, I've never seen Kempas.



Mike Hill said:


> The end user of guitar music and instruments seem to have a greater need to be different or extreme rather than good as compared to a "standard". Violins and violin music seem to be generally compared to a standard. Do I dare say that there may be a tad more reverence in conjunction with violins rather than in guitars? I've seen a few "different" violins, but they don't seem to have caught on as powerfully as the "different" guitars.


Nice explaination!


Arn213 said:


> You would have to build “guitars” in order for you to also change your misconception that a guitar is not a “fine tweaked or a well engineered musical instrument”.


Agreed 100%.

Maybe it's just that the Guitar works in such a way that its material is not as important as it is for a Violin.

Thanks for the archtop guitar pictures!



Arn213 said:


> You have to find me a study that proves that “curly maple” or “figuring” makes better tonal properties


This I don't know, I was just thinking...


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## phinds

chatometry said:


> That maple picture was exactly what I had in mind to see the effect.
> Why do you say that the side grain is not wavy? I would say that there is a slight waviness...


I see what you mean but that is SUCH a TINY amount of wave that it never occurred to me that it could cause strong curl and I'm still not convinced, particularly since I've seen other woods with obviously wavy grain but no curl at all. Kempas, in particular, often has wavy grain but I've never seen curly kempas. I'm not saying it doesn't exist just that I've never seen it and I have DEFINITELY seen lots of kempas with obviously wavy grain.

Bulletwood does tend to have a light curl but I did find at least one piece that had wavy grain and no curl.

I've looked back at a lot of my curly maple pics and, to my surprise, I DO usually see that tiny wave in the grain that is so small that I had discounted it.

So ... maybe you're right but I don't think so as a general broad rule. I'll pay more attention in the future and should I turn out to be wrong, I'll change my statements on my web site.


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## chatometry

@phinds
Thank you for the very fair and honest post.

And I want to thank you again and again for providing so many samples; below some more results:




Curly Etimoe - PZC = 18.5:
within the range we found from 5 other sources (17.6÷26.8)




Quartercut Bocote - PZC = 12.6: [Phinds note: this would more correctly be called quarterSAWN since quartercut is mostly not actually quartersawn but this piece is true quartersawn]
within the range we found from 7 other sources (9.5÷12.6)




Flatcut Jatoba - PZC = 12.2:
well below the range we found from 5 other sources (15.9÷22.5)




Bubinga - PZC = 23.5:
within the range we found from 5 other sources (14÷24.4)




Light Mottle Bubinga - PZC = 15.7:
within the range we found from 5 other sources (14÷24.4)




Flatcut Hard Maple - PZC = 13.8: [Phinds note: this is actually quartersawn]
just below the range we found from 5 other sources (15÷18.9)




Quartercut Hard Maple - PZC = 14.3: [Phinds note: this is actually flat cut]
just below the range we found from 5 other sources (15÷18.9)




Euro Beech - PZC = 8.6:
just below the range we found from 5 other sources (9.4÷10.7)




Eucalyptus - PZC = 13.1:
within the range we found from 7 other sources (11.1÷16.5)




Aniegre Crotch - PZC = 14.6:
within the range we found from 6 other sources (11.6÷17.8)

Reactions: Like 1 | Informative 1


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## phinds

chatometry said:


> Thank you for the very fair and honest post.


I always told my kids, I REALLY hate being wrong but there is one thing that I hate more than being wrong and that's being wrong and thinking I'm right. SO ... I'm actually happy when someone points out something I have, or may have, wrong. This leads to problems in life, however, because many other people do NOT share my point of view and would much rather be wrong than be corrected.

I see your bubinga findings are, not surprisingly, what I have observed which is that bubinga has a wide range of chatoyancy. Also, I love that curly etimoe. Beautiful wood when curly, varies a lot when not curly.

Reactions: Like 1


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## Mr. Peet

chatometry said:


> @phinds
> Thank you for the very fair and honest post.
> 
> And I want to thank you again and again for providing so many samples; below some more results:
> 
> View attachment 216467
> Curly Etimoe - PZC = 18.5:
> within the range we found from 5 other sources (17.6÷26.8)
> 
> View attachment 216468
> Quartercut Bocote - PZC = 12.6:
> within the range we found from 7 other sources (9.5÷12.6)
> 
> View attachment 216469
> Flatcut Jatoba - PZC = 12.2:
> well below the range we found from 5 other sources (15.9÷22.5)
> 
> View attachment 216470
> Bubinga - PZC = 23.5:
> within the range we found from 5 other sources (14÷24.4)
> 
> View attachment 216471
> Light Mottle Bubinga - PZC = 15.7:
> within the range we found from 5 other sources (14÷24.4)
> 
> View attachment 216472
> Flatcut Hard Maple - PZC = 13.8:
> just below the range we found from 5 other sources (15÷18.9)
> 
> View attachment 216473
> Quartercut Hard Maple - PZC = 14.3:
> just below the range we found from 5 other sources (15÷18.9)
> 
> View attachment 216474
> Euro Beech - PZC = 8.6:
> just below the range we found from 5 other sources (9.4÷10.7)
> 
> View attachment 216475
> Eucalyptus - PZC = 13.1:
> within the range we found from 7 other sources (11.1÷16.5)
> 
> View attachment 216476
> Aniegre Crotch - PZC = 14.6:
> within the range we found from 6 other sources (11.6÷17.8)


You have the flat cut and 1/4 sawn hard maple reversed

@phinds 

Curly Etimoe, don't have any in the collection... and yet another one to look for.

Reactions: Thank You! 1


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## phinds

Mr. Peet said:


> Curly Etimoe, don't have any in the collection... and yet another one to look for.


I've never had any solid curly etimoe, just veneer.


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## TurkeyWood

To scale the discussion back a bit, the 2 woods I have that have chatoyance that is easily observed are Chechen and Bubinga.


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## chatometry

Thank you.
Our numbers too confirm that Bubinga is (often) highly chatoyant.
As for Chechen, we do not have enough samples to start processing it, and I have no first-hand experience on it. We will definitely look for more samples!


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## chatometry

More results from @phinds 's samples:




Light Figure Aniegre - PZC = 15.7:
within the range we found from 6 other sources (11.6÷17.8)




Figured Aniegre - PZC = 11.1:
just below the range we found from 6 other sources (11.6÷17.8)




Quartercut Aniegre - PZC = 14.5:
within the range we found from 6 other sources (11.6÷17.8)




Santos Rosewood - PZC = 13.8:
within the range we found from 5 other sources (8.5÷15.7)




Makore - PZC = 18.8:
within the range we found from 6 other sources (17.6÷26.8)




Makore (Quartercut Figured)- PZC = 17.8:
within the range we found from 6 other sources (17.6÷26.8)




Makore (Mottled)- PZC = 19.9:
within the range we found from 6 other sources (17.6÷26.8)




Makore (Mottled) - PZC = 19.7
within the range we found from 6 other sources (17.6÷26.8)




Sapele (Ribbon Stripe)- PZC = 22.8:
just above the range we found from 6 other sources (14.1÷22.4)




Sapele (Block Mottle)- PZC = 19.4:
within the range we found from 6 other sources (14.1÷22.4)

Reactions: Informative 1


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## Mike Hill

Back to violins. It says the world's biggest violin - and dated 1912. Wonder what tonewoods they used and if they actually found a quartersawn billet big enough? Looked they had to borrow some cut-offs from the golden gate bridge to make the strings!

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## Mr. Peet

Mike Hill said:


> Back to violins. It says the world's biggest violin - and dated 1912. Wonder what tonewoods they used and if they actually found a quartersawn billet big enough? Looked they had to borrow some cut-offs from the golden gate bridge to make the strings!
> 
> View attachment 217128


Finding 1/4 sawn back then in large stock easier than now. As for wood, a curiosity, but more interested in how it sounded...

Reactions: Agree 1


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## chatometry

We tested some more of @phinds 's samples.

Briefly, 12 out of 14 species gave PZC values within the ranges we found on samples from other sources.

2 species gave different results (significantly):

Koto: PZC found = 17.5 (vs 10.1÷12.5 found on 6 other sources)

Yellow Poplar: PZC found = 15.0 (vs 10.4÷12.1 found on 7 other sources)

Below some nice examples :)




Louro Faia [Phinds note: this is lacewood, almost certainly Brazilian]




Black Cherry




American White Ash




American White Ash




American White Ash




Koto




Zebrawood




Aspen




Teak




Padouk

Reactions: Way Cool 1 | Informative 1


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## phinds

Very cool.

American white ash is a bit of a surprise to me. I don't think of it as chatoyant.


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## chatometry

In fact the values are medium-low (9÷14), similar to Fr. Excelsior (9÷16), but the presence of figure or porous rings makes it quite visible. Again, what you see are just pictures of a 1500-grit sanded surface.

I must point out that chatoyance is best seen under ONE light source; a room with diffused light or a light projected against a large white wall will not do the job.


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## phinds

@chatometry, I've made a few annotations/corrections to your posts. In general, when something is true quartersawn, you should call it that, not quarterCUT, which is a cut that mostly does not produce quartersawn lumber.

Reactions: Thank You! 1


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## phinds

chatometry said:


> I must point out that chatoyance is best seen under ONE light source; a room with diffused light or a light projected against a large white wall will not do the job.


Yep, I agree.


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## Karl_TN

@chatometry, This is a very long thread so maybe this was covered, but I’ll risk asking anyway. Have you tried checking for chatoyancy before and after roasting a piece of curly maple (or other wood that do well with torrefication)?

See this thread for more details at my roasting test: https://woodbarter.com/threads/torrified-maple-test.46739/#post-649347


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## chatometry

@Karl_TN thank you. I will dig through this and come back to you with some questions...


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## chatometry

Well... we are not equipped for roasting wood :(
I will see if I can find someone who can bake some...

Have you tried other wood types?


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## Karl_TN

chatometry said:


> Well... we are not equipped for roasting wood :(
> I will see if I can find someone who can bake some...
> 
> Have you tried other wood types?


See the list of torrefied woods at this site:

https://www.curlymaplewood.com/Roasted-Torrefied-Woods_c_89.html

Once you see the prices then you will understand I’m choosing to do the roasting at home. Luckily my wife wants a new oven soon so she doesn’t mind me experimenting with our old stove as long as the fumes can be exhausted outside.

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## Arn213

chatometry said:


> Well... we are not equipped for roasting wood :(
> I will see if I can find someone who can bake some...
> 
> Have you tried other wood types?


You don’t need too- being that you are in Europe, there are Scandinavian countries who introduced this thermal treatment. You should be able to find vendors for flooring, decking, sauna and for guitar building woods that you should be able to get samples from. Just make sure you get the color range that goes from violin amber to the darker amber root beer. Pretty sure that will affect the chatoyance grading going from light to dark.

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## chatometry

Thanks for the suggestion.

We tested samples from 12 more logs confirming Koa as n.1 for chatoyance. 
These are some nice examples:

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## 2feathers Creative Making

chatometry said:


> Thanks for the suggestion.
> 
> We tested samples from 12 more logs confirming Koa as n.1 for chatoyance.
> These are some nice examples:
> 
> View attachment 217419
> View attachment 217420View attachment 217421
> View attachment 217422
> View attachment 217423
> View attachment 217424
> View attachment 217425


Tempted to see if I can make that set into a screen saver!

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## chatometry

If you wish to try I can provide higher resolution gifs...

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## 2feathers Creative Making

chatometry said:


> If you wish to try I can provide higher resolution gifs...


Thanks but I only use a cell phone. I don't even know how to switch screen savers on it. It is a very nice set of pictures though.

Reactions: Like 1


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## chatometry

We uploaded a lot of gifs on these pages, split by type of figure.



Curl – PZC Chatometry





Ribbon Stripe – PZC Chatometry





Other Figures – PZC Chatometry





Flecks – PZC Chatometry





Growth Rings – PZC Chatometry



I just wanted to highlight this one below; not nice indeed, but due to the presence of flecks it shows just barely visible chatoyance on wenge, which I had never noticed before.

Reactions: Way Cool 2 | Informative 2


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## phinds

Very cool. Thanks for posting.

Reactions: Thank You! 1


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## chatometry

For those of you who (like me) had never seen some chatoyant Cocobolo; as usual, no finish and sanding up to 1500-grit.







These are just to show nice examples on other wood species...

Kingwood:




Sapele:




Birdseye Maple:




Oak [sold as Sessile Oak]:

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## chatometry

A couple of nice samples from @phinds:

Birch (guess the light path above the sample...)




Paldao

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## chatometry

We have a new n.1!!!!
Data from Australian Blackwood (30.0 PZC on average of samples from 7 different logs) are much higher than Koa (26.4 PZC on average of samples from 20 different logs).
However from my limited experience, and @Arn213 may support on this, Koa is significantly more figured on average.

Another interesting new find is Queensland Maple (Flindersia Brayleyana) with more than 24 PZC on average. Does this match you experience?

Paolo

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## chatometry

Some examples, all sanded to 1500-grit and no finish.
Blackwood:




Queensland Maple:




Queensland Walnut:

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## Mr. Peet

chatometry said:


> We have a new n.1!!!!
> Data from Australian Blackwood (30.0 PZC on average of samples from 7 different logs) are much higher than Koa (26.4 PZC on average of samples from 20 different logs).
> However from my limited experience, and @Arn213 may support on this, Koa is significantly more figured on average.
> 
> Another interesting new find is Queensland Maple (Flindersia Brayleyana) with more than 24 PZC on average. Does this match you experience?
> 
> Paolo


Is your Queensland Maple of a commercial origin? The color expressed does not match well with _F. brayleyana _but does better with _F. pimenteliana_. Same thoughts when looking at vessel lengths.


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## chatometry

The gif I posted is from a commercial source which, however, seems quite reliable to me. Anyway, this one looks similar:



The source for this one is reliable: edit: Carlton McLendon

Reactions: EyeCandy! 1


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