CMYK refers to the four-color process used in printing, particularly in inkjet and professional photo printers, to produce full-colour images. The three primary subtractive colours-cyan, magenta, and yellow-combine to create a wide range of hues, but mixing them alone produces a muddy black. To achieve true black and improve image density, a separate black ink (K) is added. CMYK printing is essential for producing high-quality photographic prints, brochures, and other printed materials, ensuring accurate colour reproduction and deep contrast in final images.