Dithered Shading

A pixel artist's bestest best friend

If you were given a box of 100 crayons and asked to color a picture of a hand, you would probably pick only one color out of the box, peach or maybe a brown, and hastily fill in the lines. But that hand would look flat, lifeless. Perhaps you take out a second color, darker than the first, and add a little bit of shading to the hand to give it some shape. It looks a little better now, but no one would ever comment on how life-like your two-color hand looks -- And not just because you are using crayons!

In real life, you come in contact with millions, even billions, of colors in a day. You probably never take notice or stop to think about it. But look at your hand on the mouse right now -- More than likely, there are a hundred different shades of tan or brown, blues, greys, reds, pinks, even purples, when you look closely enough. No object, even what seems to be a perfectly blank piece of white paper, ever contains only one shade.

Most modern computer monitors are now able to display millions of colors and shades, plenty enough to fool the eye into seeing photographs displayed digitally as realistic. But if you are a furcadian pixel artist doing remappable ports, you don't get the benefit of those millions of colors. In any given category - fur, markings, clothing - you are given only nine shades to work with. This is big trouble for any artist attempting to create subtle shading. As you know, an abrupt transition between light and dark will almost always be perceived by the eye as a sharp angle, the division between two planes, like the top and side of a box. This can be particularly distressing while shading things like faces, which, for the most part, are very gently sloping surfaces with only a very few sharp divisions between light and dark - for instance, if the person has high cheek bones or deep set eyes.

Thousands of shadesNine shades

Look at the two pictures above. On the left is a black and white photograph that has thousands of shades of grey in it. Things are smooth, the texture of the fur is soft. On the right is the same photograph, compressed into only nine shades. It's okay. You can still tell what everything is. But things look much rougher. It's not nearly as sensitive a rendering as the first image. As an artist, except in certain stylized cases, you probably want to be able to produce renderings more like the first image. Sensitive and subtle.

So what can you do? Many artists turn to cel-shading. This is one of the most common digital shading techniques, when a mid-tone is applied between a lighter and darker color to help ease the eye's transition between them, making their progression look smoother. But this can be difficult when you are working with only 9 shades. You may find yourself quickly running out of mid-tones.

Cel Shading

When working with such a limited palette, every pixel artist should know something about dithering. A dither is a pattern using two colors, to create the illusion that there are more. Dithering is never random. Don't be tempted to use an "air brush" tool that will fling random pixels around. There are no shortcuts. A good dither must be patterned or it will turn into nothing more than a distraction.

A few dithering patterns.

Below is an in-progress sample of a portrait I did a long time ago. Compare the image on the left, which has the shading thoroughly blocked out - We know from looking at it what parts of the face are in shadow, and what parts of the face are most exposed to the light. Now look on the right. It's the same facial structure, but the edges have been blended with just a little bit of dithering.

Almost there...Eureka!

Now imagine that you have a nearly completed portrait. You have paid close attention to getting the proportion correct, you have thought hard about where the light source is coming from and not been afraid to use every shade available to you, from the darkest to the lightest. When there are only nine colors available to begin with, you simply can't let yourself be shy about taking advantage of all of them. It looks good. You are proud of it. But before you upload it, you want to give it that extra touch to make it truely smooth.

This port is nearly done... But it could use some dithering!

Get in there and start dithering. I prefer the smallest, tightest dithering pattern when working with faces, but others are possible and you can use more than one in different locations.

Right now, she has highlights on her cheeks, forehead, nose and chin. But I don't want it to appear that these areas are leaping drastically forward, mountain peaks in the center of an otherwise smooth face. By dithering around the edges of these highlights, I make them softer, subtler. They give a gentler shape to her face when they transition smoothly.

I will also add a tiny bit of dithering around the eyes, beneath the lips, and around the edges of the face. Because I already took the time to block out the relevant light and dark areas, it isn't difficult at all. It's just a matter of recognizing where an edge might benefit from being a little softer, and taking a few minutes to pattern it. With practice, it will become natural.

What a difference!

Now that my face is fully dithered, I can go ahead and add markings or any other tiny details, and call it a day!

Dithering is a very powerful tool for the savvy pixel artist working with a limited palette, but that doesn't mean it's appropriate in every situation. Some materials do not look very good when dithered - hair or highly reflective surfaces like glass or metal, for instance, rarely work well when dithered. In addition, different dithering patterns can also affect the texture of your drawing. This can be helpful or harmful depening on what the object is. Experiment with many different dithering patterns to find the ones that work best in different situations.

Please feel free to download and use this finished portrait in portrait spaces or dreams. Also feel free to edit. But please be respectful: Don't claim to be the original artist, and give credit where appropriate.

Click the pic to download

Hair remaps to hair, Lips remap to boots, eyeshadow remaps to markings.