Shades of cyan 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 cyan 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 cyan ink. A typical formulation of "process cyan" is shown in the color box at right. The source of the color shown at right is the color magenta that is shown in the diagram located at the bottom of
Shades of magenta a single wavelength. Humans, being trichromats, can only see as far as 380 nanometers into the spectrum, i.e., as far as violet. The hue magenta is the complement of green: magenta pigments absorb green light, thus magenta and green are opposite colors. Before "printer's magenta" was invented in the 1890s for CMYK printing, and "electric magenta" was invented in the 1980s for computer displays, these two artificially engineered colors were preceded by the color displayed at right, which is the color originally called "magenta" made from coal tar dyes in the year 1859. Besides being called original magenta, magenta dye