color wheel - A radial diagram of colors in which primary and secondary, and sometimes intermediate colors are displayed as an aid to color identification, choosing, and mixing. A color wheel with primary (red, yellow, blue) and secondary (orange, green, violet) colors can be seen to the left below. The complement to each color is the color opposite that color on the color wheel. To the right below are diagrams of complementary colors, demonstrating the ratios devised by Johannes Itten, in response to these colors' relative intensities and values.
This commercially available color wheel is based on the primaries of red, blue, and yellow -- CMYK primaries (cyan, magenta, and yellow, along with black) -- used when mixing pigments. How do you mix Kelly Green? What do you get from yellow and purple? How can I mix a certain brown? A color wheel is a very handy reference for answering such questions.
This commercially available color wheel is based on the CMYK primaries -- cyan, magenta, and yellow (along with black). It also references subtractive color mixing -- using the RGB (red green blue) primary colors used when mixing light. Dye is transparent and therefore mixes much like light. This color wheel is more useful for mixing dyes than opaque paints.
Also see color, hue, palette, saturation, shade, tint, tone.