Cyan, magenta, and yellow form the base triad of subtractive color mixing in printing. By layering these three transparent inks, presses filter out red, green, and blue light from the white paper beneath. While theoretically capable of mixing to true black, impurities in real-world inks mean they combine into a muddy brown, which is why a black plate is usually added for high-quality reproduction.
Check the CMY balance on that proof because the grays are leaning way too far into the magenta.
Related terms
CMYK
The standard four-color printing process that combines cyan, magenta, yellow, and a key plate of black ink.
Process color
A printing method that mixes four standard ink colors to reproduce full-color images.
Color separation
The prepress process of dividing a full-color image into individual primary color channels for printing.