There are many schools of thought on this topic. The best way for me to explain color is to begin with value. As a painter, learning how to see a color’s appropriate value and translate that into a tonally and chromatically balanced painting is the ultimate goal. That can be very difficult for the beginning painter as there are so many choices of colors and without a specific approach to simplifying those choices their paintings can easily loose coherency. The way that I teach painting is built upon the same principles of drawing. This allows for a very natural progression into painting, as it is, essentially, an extension of drawing.
Think about the way that certain colors would appear in a black and white photograph. A yellow would appear as a light grey; a red would be close to a mid-tone grey, and a green would be yet significantly darker. All colors have a corresponding “value”. In painting, every type of grey can be achieved by mixing portions of black and white together.
Many artist’s use this technique to serve as an underpainting which will eventually be glazed over in color. This works extremely well for the beginning painter as it allows for him or her to simplify the painting process into two stages — value first, then color. Establishing the values first will influence the painting in it’s entirety. Colors are added on top as translucent washes and are meant to enhance, rather than drastically change the tonal underpainting. The technique is called grisaille which is a french word, meaning grey tones.
In the nineteenth century students of the ecole des beaux-arts, were only allowed to paint in color, once they’d mastered painting in grisaille. Often plaster casts were set up as props with strong spot lights so that students could really analyze the play of light and shadow on forms without color.