What Flaming Overlords like.

For example, check out Jasmine and Mulan. Both of them have black hair, but we get subtle differences between them. 

Mulan, for example, has hair made with dark brown lines. We get the idea that her hair is probably a very deep, deep shade of brown, or that as light filters through her hair, we’re seeing that brown subsurface scattering.

Jasmine, meanwhile, has hair that is so deep black we sometimes see it as blue. This is black hair with cool undertones, as opposed to Mulan’s hair with warm undertones. Which in pure color speak is impossible, but is something that happens with hair, since hair is mildly translucent and reflective. 

You can even compare that further with Esmeralda, who has grey lines that give the illusion of neutral undertones.

They can also use color to give characters that fantasy feel or the feel of completely unnatural hair. Princess Aurora, for example, has technically darker hair than Charlotte LaBouff. But, with the lighter outlines? Aurora’s hair looks absolutely fairytale golden, while Lottie’s looks like a more natural flaxen blonde.