HRH The Duke of Edinburgh

[OC Richard]

Yes these colour terms get silly, but still, "grey" often is used to refer to a "cool" grey while "putty" and "mushroom" respectively usually refer to greys that are progressively warmer, with a bit more brown in them, on the continuum between white and brown (while grey is on the continuum between white and black). If I were selling something halfway between an ordinary cool grey and taupe, I probably wouldn't call it "grey" but possibly "mushroom" or "putty" and most people would know what it meant.

So in the lower photo Charles' hose I would call "grey" but his kilt "putty". In the upper photo I would call Philip's kilt "tan".

BTW it's a strange oddity of English that there are so many colours which we don't have words for, but for colours in between white and brown we have a large number of words for (beige, tan, khaki, bone, ecru, buff, oatmeal, fawn, sand, camel, taupe, putty, mushroom, biscuit, and who knows what else).