Why Pheomelanin?

[Bert45]

It was a question on "The Chase": An abundance of the pigment pheomelanin gives people which hair colour? Answer: red. I looked for the definition and etymology with Google. It is a"a reddish-yellow sulfur-containing melanin pigment" and 'pheo' comes from the Greek phaiós "a shade between black and white, gray, dark gray" (of obscure origin). Why would a reddish-yellow pigment be given a name meaning grey?

[douglas9401]

It's only used after a comedy bomb has gone off leaving only a grey, powdery residue where the victim's hair used to be.

[Khandro]

If you take a picture of a red-headed person and desaturate it , as you can in Photoshop or on some cameras, it will appear as grey.

Possibly also to the colour-blind; I'm not one of them so I don't really know.