This page describes how to use 是 properly in sentences:
是 (shì) is only used to link two nouns. It cannot be used to link a noun and an adjective. This is a very common mistake for people just beginning to learn Chinese. For that kind of sentence, you'll want to use a different structure with the linking word 很 (hěn).
It makes sense, but one pattern is not clear.
Take for example: "All her clothes are black."
Would you say， 她什麼衣服都很黑色，since you cannot say， 她什麼衣服都是黑色？
It seems strange to say 很黑色 in this context, so confirmation would be most appreciated.