Scarlet is a bright red color, sometimes with a slightly orange tinge. In the spectrum of visible light, and on the traditional color wheel, it is one-quarter of the way between red and orange, slightly less orange than vermilion.

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.