This makes me think of a bay laurel coffee table I made once. If you looked at it from one end, the 1/4 sections would be dark and light. If you looked at it from the other end, the dark and light reversed. If you looked at it from the side, it was pretty much all the same color. I will check out that article. Oh, I did see a set of folding screens, the privacy types, maybe in Fine Woodworking. The artist made them according to how light reflected off of them to make a pattern with it. Pretty stunning! I could never make some thing like that, I don't have that type of imagination.
Hmm, well, it seems that softer woods have a lower rating than harder or denser woods. No Koa on the list, or Cuban mahogany, or Bay Laurel. For sure, these woods will "glow" far more than most others. I guess I can see what they are measuring, but it didn't really clear things up for me. What I am still wondering was how fine were the surfaces sanded to, or were they hand planed which will leave a more shiny surface....
robo hippy
I don't think there was any particular special processing of the woods. Basic planeing with a thickness planer was what I thought from my last exploration of their process. They have not tested all woods. I've been working on a project myself the last couple of months, a web app that will use AI to identify woods. In that process, I have had to explore a LOT of data on woods, find a LOT of images to train the AI. I've discovered there are over 500 types of wood, closer to 600 I guess... So, I don't think that this Chatometry project is even close to cataloging all woods. It'll take time.
The effect is the same in all woods, where the fibers reflect and disperse light a certain way. This creates that "band" of brighter reflectiveness. One of the key attributes that is different with every wood, is the scale. Highly chatoyant woods tend to have a smaller scale...the bright band of chatoyance is narrower with these woods, and more light is concentrated in it, so its more notable. Other woods have a much larger scale, the band of chatoyance is very broad. So the light is not as concentrated, and it may not even look like a band (i.e. in total scale, it could be feet wide rather than inches or less!) However the effect is the same, and it is chatoyance, and the study is demonstrating that most likely, all woods exhibit the effect, to one degree or another...meaning it is a matter of degree. So while some woods are HIGHLY chatoyant, like some of the ones you mentioned before, others are not, even though they still exhibit the effect.
I was turning some fairly bright white sycamore the last couple of days. Because of this conversation, I was wondering about it, as sycamore doesn't exhibit a lot of reflection, so I started taking a much closer look. As it turns out, it DOES exhibit chatoyance, but its different than other woods due to the nature of the fibers. There are the very fine whiter fibers, which do reflect light and you can see faint chatoyance...however there are other fibers, tan or browner in color, that are more scattered and widely separated in the wood. These fibers actually exhibit fairly strong chatoyance. The effect doesn't look the same as say highly figured maple, which for me is some of the most chatoyant wood I currently own, and because of the widely spaced fibers, the band of chatoyance is really huge (probably a foot wide or so, so on these smaller pieces that are just a few inches in size, much larger than the piece.) I can however, with just moderate direct light, clearly see the chatoyant reflections off of these tan/brown fibers throughout the wood grain, and it is a shimmer just like any other chatoyance. The wider spacing of the fibers makes it harder to see, but the effect is the same. Shellac or oil finish does improve the depth and appearance of the effect. It is a bit of a glow, but that glow exhibits a shimmering as the pieces are rotated around in the light. So I wouldn't say its JUST a glow...it is chatoyance.
I think the key is that, chatoyance is the result of light reflecting off of aligned fibers, not just on the surface but a little ways into the surface of the wood, and the physical characteristics of that reflection, where light may bounce off of one fiber and onto then off of another, etc. etc. that creates a band of reflection. It is also more than just reflection, at these scales diffraction plays a role as well, which is why the effect can occur even when some of the fibers are separated from each other, as in the case of the sycamore. The band scale can vary, but the fundamental physics of what's happening are the same.
So you have come far and now the journey asks more of you. It could be worse, the first day where everything aint working and the mountain is very steep..
)
