A Color wheel is a diagram that maps colors by their relationship to the other colors on the circle. While colors that are related to each other are placed side-by-side, complementary colors (colors that are inversely related to each other) are put on directly opposite sides of the color wheel.
In the color wheel, red, yellow and blue are considered primary colors while orange, green and purple are secondary colors.
The difference between primary and secondary colors on a color wheel lies in the fact that different blends of the three primary colors are responsible for creating each of the secondary colors.
When looking to find color balance in a photograph, it’s important to match complementary colors. The three different color systems are based on different combinations of primary colors.
RGB, the color space that most cameras use, is based on a Red/Green/Blue color wheel. The CYM color system is modeled with a Cyan/Magenta/Yellow color wheel. Finally, the RYB system relies on a Red/Yellow/Blue color wheel. The distinct color system a camera uses will produce an image within a defined color wheel. While painters rely on an RYB color wheel, photographers tend to capture their shots with either the RGB or CMY color wheel systems.