After a few years of self taught DIY, from hobby to hobby and various shenanigans and my latest landing was artisan keycap making, this is my theory on how dyes molecularly affect the microstructure of plastics. For short, how you can change your switches' sound and feel without changing the material, but instead, change it colors.
A few terms need to be clear out
- Opaque: no light go through;
- Translucent: let parts of light go through, changing light's intensity, color
- Transparent: let most light go through, clear, no color
First, nylon 66, polycarbonate,... are transparent when pure. Their molecular connections are very organized, that's why light can go through.
Next, mixology, if you want translucent plastic, add simple color/dyes, want to make it opaque, add white as base, even housings such as cherry black need white mix into it. Why? Because white dye have the biggest particle size, it helps to prevent light from going through. (also it's the reason why it's impossible to have white anodized aluminum, it's just too big to get in the pores on the material's surface after etching). Example: Tangerine housing only need orange dye, Tecsee's Carrot housing need orange + white dye.
Therefore, in my theory, opaque plastics should have a deeper sound than translucent/transparent plastic because the big white dye particles sneak between the polymer's structure, creating "pores" at the molecular level, absorbing more sound. And also make it have more friction, add more molecular connections flex to the material? Is this why translucent KBD lite cases have the tendency to crack compare to opaque ABS?
If you want to make a Tangerine sound deeper, make the housing opaque. Why Epsilon switches are smooth and thocky? Translucent nylon housing produces deep sound to make up for the P3 stem higher pitch sound, the self lubricating nature of UHMWPE (P3 is a UHM mix) adds up with the smooth translucent nylon surface. Maybe a switch with Epsilon's stem, same housing material but in a opaque color will sound deeper but not as smooth?
Anyway, this is my theory, I don't have any scientific device to prove it (sound, surface texture). Feel free to widen my knowledge.