RYB is a subtractive color model used in art and applied design in which red, yellow, and blue pigments are considered primary colors. Under traditional color theory, this set of primary colors was advocated by Moses Harris, Michel Eugène Chevreul, Johannes Itten and Josef Albers, and applied by countless artists and designers. The RYB color model underpinned the color curriculum of the Bauhaus, Ulm School of Design and numerous art and design schools that were influenced by the Bauhaus, including the IIT Institute of Design, Black Mountain College, Design Department Yale University, the Shillito Design School, Sydney, and Parsons School of Design, New York.

Red is the color at the long wavelength end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–740 nanometres. It is a primary color in the RGB color model and a secondary color in the CMYK color model, and is the complementary color of cyan. Reds range from the brilliant yellow-tinged scarlet and vermillion to bluish-red crimson, and vary in shade from the pale red pink to the dark red burgundy.