Color and Light in Digital Photography: DDigital Camera Color and Vision Basic Theories

constitutes a third of the visible spectrum. The sum of the light of the three in the same proportions gives white light, and each one has nothing in common with the other two. Any color can be considered as a sum of determined proportions of these three primary colors. In all possible colors, there are three which are of special importance in photography: the ones obtained from the sum of two primary colors. This way the three secondary colors are obtained; each one of them can be considered:

• •  the sum of two of the three basic colors (two thirds of the visible spectrum); or as well,
• •  white light minus the color that isn't in the sum (white light minus a third of the spectrum).

The colors obtained are:

• •  yellow:
• •  sum of red and green;
• •  white light minus blue;
• •  magenta:
• •  sum of red and blue;
• •  white light minus green;
• •  cyan:
• •  sum of blue and green;
• •  white light minus red.