Dithering

CMYK printer palette

4 colors CMYK : Cyan, Magenta, Yellow, Black (and bonus White color as well because the paper is white when a pixel is ignored).

Although not as accurate as having a properly chosen set of colors,the CMYK palette is a good "all around, jack of all trades" palette, especially when dithering is applied.

The CMYK palette is therefore the goto palette for almost every printers in the world.

Original

CMYK Colors (Printer Palette)

Floyd Steinberg palette dithering

Wether the goal is to paint on paper, or to reduce the size of an image perhaps for steganography purposes or whatever floats your boat, reducing the image number of colors may be done while keeping a fair amount of details using the CMYK palette. It is more for printing though than screening because light and paint have different properties : paint darkens and light... well... lightens the colors.

CMYK Printer Palette Dithering