Color Resolution and Dithering

Whenever you reduce an image's color resolution to 8 bits per pixel or less, a dithering method comes into play. Dithering methods create the appearance of more subtle shades by mixing in pixels of different colors. This is similar to the way newspaper pictures produce the appearance of shades of gray, even though the only actual colors are black and white.

Variations in Dithering Methods

Original Image

Ordered Dithering

Error Diffusion Dithering—Floyd-Steinberg