Image Dithering: Eleven Algorithms and Source Code

I still use dithering daily with 24 bit color images. In fact, my test for whether a modern image editor is serious and good is whether it supports dithering when converting from floating point color channels down to 8 bits per channel. Photoshop does this. The most important reason for me is not display on the monitor, but printing the image. I do a lot of large format printing, and printers smash parts of your color space and make some…

The article doesn't put enough emphasis on the need for gamma correction. If you dither a pure gray area of level 128, it will become approximately 50% white and 50% black. But when you display that back on the screen, because of gamma effects it will look closer to a level of 186! A few years ago there was a need for 15-bpp or 16-bpp color images on phones rather than the 24-bpp images we usually work with, and dithering…