Cyan. Cyan is a greenish-blue color. It is one of the primary subtractive colors used in color printing. On the traditional color wheel, cyan is located midway between blue and green. It was usually called called blue-green. The name cyan or cyan-blue was first used as a color name in the 19th century.In the subtractive color model, cyan is the complementary color of red; mixing red and cyan paint will produce a gray color.he name cyan or cyan-blue was first used as a color name in the 19th century. In the subtractive color model, cyan is the complementary color of red; mixing red and cyan paint will produce a gray color.