What’s the chemistry at play here to achieve this?
Does it burn “lighter” compounds away to leave dark ones behind? Does it cause a reaction to turn lighter compounds darker? I couldn’t see details of the mechanism. Which is important since presumably some mechanisms would give a hint that the process can be tried on other materials or types of wood.
The article mentions it works on other types of wood but doesn’t explain why, or if it works on all woods.
It's probably a combination of the surface being black in colour (charcoal), plus a surface texture that absorbs light.
It brings to mind the way feathers and insects often have brightly-coloured parts that aren't due to pigment but rather the microstructure preferentially absorbing/reflecting specific wavelengths, giving a colour.
Well they say it doesn't rely on pigments, so I'm inclined to think it uses some sort of nano-structures, like "improved" vantablack. Like a forest where light goes in, but just get's scattered long before it can make its way back out. Ben did a really nice video about that homemade stuff, including (of course) some electron microscope images.
Two things are at play, the lignin (light absorbing) is emphasized and the cellulose is burnt away (light reflecting), and it seems this combined pretty unique lattice system (they use a similar synthetic system when producing regular ultrablack paint but the natural one appears to be more complex) create the blackness.
Does it burn “lighter” compounds away to leave dark ones behind? Does it cause a reaction to turn lighter compounds darker? I couldn’t see details of the mechanism. Which is important since presumably some mechanisms would give a hint that the process can be tried on other materials or types of wood.
The article mentions it works on other types of wood but doesn’t explain why, or if it works on all woods.