Q: Some friends from work were wondering if it’s correct to use colors in the plural when they’re nouns. We have a team called “Amber,” and we’re usually referred to as the “Ambers,” like my neighbors, the “Greens.”
A: There’s nothing wrong with that terminology. Words for colors aren’t just adjectives, as in “a pink dress.” They’re nouns, too, and even verbs.
As nouns, they can refer to the colors themselves (“Mix blue and yellow to get green”) or to things of that color (“If I bring wine, do you want a white or a red?”).
Such nouns can of course be pluralized, as in “There are so many different greens in the landscape,” or “The carriage was drawn by two dappled grays.”
And groups of people are commonly referred to this way as well: “The Reds meet the Phillies tomorrow at 4 p.m.” … “Participants re-enacted battle scenes between the Blues and the Grays.”
So members of a team known as “Amber” would naturally call themselves the “Ambers.”
We also use some color words as verbs meaning to turn that color: “First, brown the chicken” … “The sun may yellow the drapes” … “The lawn has greened up nicely.”
As for those neighbors, the “Greens,” this is simply a pluralization of a surname, like “the Smiths” or “the MacGregors.”
Many surnames happen to be the names of colors: “Black,” “White,” “Gray,” “Green,” and “Brown” are probably the most common.
A reader once asked why people have those color words as surnames, but almost no one is “Mr. Yellow” or “Ms. Purple.” As you can see from our reply, there’s no black-and-white answer.
from Grammarphobia http://www.grammarphobia.com/blog/2016/04/color-2.html