What this article doesn't answer is, when it talks about the green soldermask being physically superior, is that only because it's had more R&D put into it due to being popular, or would it actually be the best regardless? (Admittedly, I don't know how one would possibly answer that question without, like, actually trying to invent better soldermask of other colors. But it bugs me that the article doesn't even ask the question.)
Solder dams come down to a bunch of factors, but the bottom line is basically the best dye is the one that lets the resin cure stable and strong.
For instance, white dyes are hard (for a lot of things) because white dye particles are large[1] and you need a lot of them. That means they can interfere with curing.
Green dye can be relatively small amounts since green is so visible to the human eye, but afaik its more down to the fact that theyve been able to tune the dyes down better over time.
[1]: also why you can't dye anodized aluminum white. Most dyes are colored at the molecular level, and are much smaller than the wavelengths they reflect. White dyes need to reflect every wavelength, and normal molecules only reflect quite narrow ranges where they resonate.
In order to reflect white light you need particles at minimum the size of the wavelength. Then you need a range of particles for each wavelength. In practice this judt gives you black, since each particle will also be absorbing light at other wavelengths. You need one size of particle with fine, often fractal-like microstructure that has features at every size. That means white dye particles are hundreds of times larger than colored dyes.
