... I... went overboard.
But, the thing with yellow, skintone and purple is that they are useful together. Our minds read yellow as skintone when used on faces, and skintone as yellow when used on... bananas. It's sort of how a paper will almost always look white, outdoors, indoors or deep in the forest. The brain calibrates.
Purple is a good way to shade skintone, so if you have say, yellow, brown and purple, you can use brown to shade something like a banana, and purple to shade faces (and share the yellow for the lit areas). Now the yellow will look even more like yellow in one case and skintone in another.
Because you mentioned GBC, I went ahead and used only 3(4) colors. I don't know what I did with the hair. Derailed, I guess. It's now a cap (probably magical and talking).
