A study into dithering.

Published: 2 Feb 2020

Definition of dithering

Lets start with the definition:

"Add white noise to (a digital recording) to reduce distortion of low-amplitude signals."

Ok.. that didnt help what about wikipedia:

"Dither is an intentionally applied form of noise used to randomize quantization error, preventing large-scale patterns such as color banding in images. Dither is routinely used in processing of both digital audio and video data, and is often one of the last stages of mastering audio to a CD."

Ok.. how about a picture.

A generic square placeholder image — wiki https://en.wikipedia.org/wiki/Colour_banding

Here we can see that the dithering option obviously has a smoother transition in colors. See it as a way to smooth out your song/image, this is often used in media processing to reduce errors/faults.

Ok cool, so what ?

Well, it is very usefull in pixel art!

Not only can we use it to smooth out some colors, introduce cool patterns to make transitions more interesting and even 'fake' some extra colors!

Faking colors

Take a look at this picture, I believe it was made somewhere in the 90's on a old Mac machine, with no access to dithering tools. How many colors do you see here ?

It is just black and white, dithering gives us the ability to fake some colors by having two different colors close together that they look like a third color, in this case grey. Older hardware like CRT screens had this effect where 2 colors would bleed over into a new one.

Applications troughout history

Dithering is not as important as it used to be, most our machines can display plenty of colors so there is no need to fake the pressence of additional colors anymore, but there was a time where this was not the case. Back when game developers had limited tools to work with, they had to get creative. When you only had 8 colors to play with, a trick to display a 9th color was a pretty cool trick!