Colors(Blue, Red, Purple, etc) are usually adjectives but they can also form parts of nouns too.
Colors are adjectives because they describe nouns(people and things)
I like the red sweater.
This dolphin is blue.
The color blue in this example describes the dolphin so therefore “blue” is an adjective.
An adjective describes a noun.
Colors as Nouns
Colors like blue and red usually only function as nouns when they are part of a compound noun that comprises of an adjective(yellow, red, etc) and a noun(person or thing)
We went through a purple patch.
You should buy some blue-chip stocks.
Colors as Verbs
Colors are not used as verbs.
If you want to say that something changes color you can use the verbs “change”, “turn” or “go”
Did you know that you can turn orange if you eat enough carrots?
The word “color”
The word color can be a noun, adjective, or verb.
All the colors in the rainbow. (noun)
Color television has been a great invention. (adjective)
Can you color in between the lines? (verb)