how colour is form?

Answer 1

Please give me more info.

Answer 2

I'm not sure what you want to know. However, I will try.

There are two ways colors are formed, additive and subtractive. Additive is combining colored lights, while subtractive is done with filters or materials absorbing various aspects of the spectrum and reflecting others.

I hope this helps. If not, repost your question in more specific terms. Thanks for asking.