Shades of magenta yellow and cyan, constitute the three subtractive primary colors of pigment. (The secondary colors of pigment are blue, green, and red.) As such, the CMYK printing process was invented in the 1890s, when newspapers began to publish color comic strips. Process magenta is not an RGB color, and there is no fixed conversion from CMYK primaries to RGB. Different formulations are used for printer's ink, so there can be variations in the printed color that is pure magenta ink. A typical formulation of "process magenta" is shown in the color box at right. The source of the color shown at
Shades of blue system are the three colors of light chosen such as to provide the maximum gamut of colors that are capable of being represented on a computer or television set. This color is also called color wheel blue. It is at precisely 240 degrees on the HSV color wheel, also known as the . It is a spectral color which lies at, or near, the short-wave (violet) end of the traditional "blue" and possibly was classified as "indigo" by Newton. Its complementary color is yellow. The color defined as "blue" in the CMYK color system used in printing, also known as