Ditherpunk: The article I wish I had about monochrome image dithering

Back when I worked at Marvell Semiconductor (circa 2005), we made laser printer ASICs for HP. We did a lot of dithering in hardware. We had a hardware block that did error diffusion, we had a hardware block that did regular diffusion. We also had a hardware block that did Blue Noise. I was responsible for implementing the firmware that drove those printers' scan/copy path: scan an image in monochrome, run through the dither hardware to create the bit pattern…

Nice historical nugget from wikipedia on dithering: > Etymology > …[O]ne of the earliest [applications] of dither came in World War II. Airplane bombers used mechanical computers to perform navigation and bomb trajectory calculations. Curiously, these computers (boxes filled with hundreds of gears and cogs) performed more accurately when flying on board the aircraft, and less well on ground. Engineers realized that the vibration from the aircraft reduced the error from sticky moving parts. Instead of moving in…

If you reduce the pixel size enough, it becomes a general purpose display technique and has no distinctive look to it. It blurs together into an average value, microscopically. A few display technologies, mostly monochromatic, actually work like this. Laser printers are an example. Generally, they are monochromatic (or quadchromatic) devices. On or off. All output is dithered. But at high resolutions like 600 dpi or more, a fine grid pattern produces a solid grey on paper.