CMYK is a colour model used in graphic and print design. The letters stand for the colours cyan (C), magenta (M), yellow (Y) and key (K), with key often representing black.

In the CMYK colour model, all other colours are created by combining these four basic colours. Each colour is specified as a percentage, where 0% means that the colour is not present and 100% means that the colour is displayed in its full intensity.

An example of the use of CMYK is the printing process. When a designer prepares an image or design for printing, they must ensure that the colours are specified in CMYK format. This is because printers normally work with the CMYK colours and the design will be printed exactly as it appears in CMYK mode. If the design is specified in RGB mode (red, green, blue), there may be colour deviations as RGB and CMYK use different colour spaces.

Another example is the creation of print media such as brochures, flyers or posters. The designer selects the desired colours for the design by specifying the corresponding CMYK values. By combining the four colours, the designer can create different shades and nuances to achieve the desired visual result.

The CMYK colour model is widely used in the printing industry as it allows precise control over colours and ensures that printed materials accurately reproduce the desired colours.