At present, the wiki page for dark skin states that sometimes characters may have dark skin due to a tan, implying that tans qualify under the tag. I understand that much.
But does this apply only to when a tan cannot be distinguished from naturally dark skin if you don't have outside knowledge of the character not usually looking so dark, e.g. post #4241904? Or, does it also apply to tans with very clear tanlines which distinguish between the character's natural skin and their tanned skin, e.g. post #10835046 (Q)?
Both lines of logic, "The dark_skin tag goes on any image of a character having any dark skin for any reason" and "The dark_skin tag ideally goes only on naturally dark skin but when a tan is indistinguishable from it TWYS means tag as dark skin", seem viable.
