The first thing to understand, is that the Dark Face Bug is not actually a bug in the game engine.
Since over the last two years I've been gaining experience and leveling up my modding skilltree, I can hopefully explain this bug in detail and in a way a casual modder will understand. I've read many discussions on it over the years, but I never saw oneI felt was sufficiently comprehensive and after seeing someone accuse Guards Armor Replacer of giving their NPCs dark faces, I decided it would benefit the community to have a more in-depth guide on the Dark Face Bug. This can be a frustrating problem to fix if you don't yet know what can cause it.
Most Skyrim modders who downloaded mods which change NPC appearances have probably gotten the dark, black, brown, grey, etc.
