Why not « cinzas »?
Some colors have no plural form (colors that are also nouns), so it should be "cinza".
Are you sure about that? As natives says it should be cinzas... And I am confused. Perhaps I will ask on quora haha. Anyway thanks for helping me and other people in Portuguese. Your comments are helpful.
Yes, I'm sure about it =)
Cinzas = ashes
Why not "cinzentas"?
Even though they mean the same thing, cinza is used for a fixed color, that is, it can't be changes (os sapatos são cinza).
Cinzento is mainly used when something has become gray: O céu está cinzento no momento.