Pixel Dithering Tutorial

Dithering is a process used in pixel art to blend colors more effectively. This tutorial will help understand what dithering is, as well as how to properly do it, or develop your own technique.

Typically when a person starts out doing pixel art, they will attempt to gradually darken or lighten areas until the art looks smooth. However, unless a lot of different colors are used, people will still be able to see the color changes. Dithering blurs the edges of these changes. They'll still be visible, but it will be much cleaner and easier to look at.

Another reason dithering was used in the past was to give the appearance of more colors. This was especially useful when console hardware limited the amount of colors available. The illusion of a color could also be created by dithering two colors to make a new one. This technique was also more effective in the past due to the low quality of video, which would blur the resulting images and make it look even more blended. You can find examples of dithering in various NES and Game Boy games, not to mention all the other older consoles (SNES, Genesis, etc.).

Dithering is still effective today. I mostly use it to transition between two areas of similar color, or when shading shadowed areas or metallic objects such as pipes.

Examples of Dithering

Here is an example of a transition between various values of green, without dithering:






And now, with dithering:

Note the distinction of the line between colors is much more blurry now. On old television sets the effect would be even more blurry than it appears now on modern screens, but the effect is still distinct enough that it can be used effectively. Note at the bottom, the line can barely even be seen. Dithering tends to work best with colors that are similar, but you can use it however you want. It is best not to overuse dithering (unless you are under color/hardware constraints, or attempting to draw in that style) because if you have large areas of dithering, it distracts the viewer from the rest of the image. In this case, it is better to simply add another color rather than dither large areas.

The most basic way to start out dithering is by using a checkerboard pattern, placing a pixel every other spot. Then as you move inward or outward from the checkerboard, you space out the dots even further. Feel free to download these images and study them. You can experiment and find a dithering pattern that works for you, but it is wise to never use more than one consecutive pixel, as it tends to break the effect:






Notice the small imperfections near the top? That's from bunching up additional pixels of the same color instead of spacing them out. You want things to be uniform where possible, and dithering is no exception. Most people find smooth artwork pleasing, and dithering contributes to this aesthetic feeling if done properly.

- kethsong