Color
First, a simple but important fact:
We  don't see  things we see light. Objects have no appearance apart from light. They either absorb or reflect the light that falls upon them. White light is a combination of all the colors. When this light strikes a surface some of the colors are absorbed and some are reflected back to our eyes. If, for instance, violet, blue, and green are absorbed, and yellow and red are reflected, then we will perceive the surface as orange.  Black objects absorb most of the light that strikes them, while white objects reflect it all.