Pixel Art Tutorials

1. Definition

Texturing is a technique that involves adding local shading and details on surfaces to better represent the material of an object. This technique is of course closely linked to shading in general. This is usually applied after defining a global shading.

From left to right :

Lineart

Global shading

Completed sprite

One of the big differences between global and local shading is homogeneity. The very principle of global shading is to give a sufficiently contrasting effect between the shaded and lit areas to bring out volume and depth. Conversely, a texture must be as homogeneous as possible. It must be able to be applied on large, uniform surfaces, without making it look bad.

2. Applying a texture

A texture being homogeneous in terms of its luminosity/contrast, if it is applied to an object without taking into account the global shading, we will lose any effect of volume and depth.

A texture applied to a sphere without shading. Only the deformation of the texture can give us a clue on the shape of the object, but it is still difficult to discern. Homogeneous contrast When applying a texture to an object, shadows must also be taken into account. It is therefore important to maintain a uniform contrast between colours. A dark line separating a light zone from a dark zone should not keep the same colour between these two zones.

The color of the line will be lighter on the lighter side and darker on the darker side to preserve its contrast with the background. In the same way it is possible to apply a texture or pattern on a shaded object, by proceeding to a simple color shifting in our palette.

Combination of a texture (left) and an object that is not textured but shaded (middle).

3. Local shading

Since shading is used to highlight the bumps, there are generally two possible cases:

A groove

A bump

Each of these cases can be more or less accentuated by playing on the colors, the intensity of shadows and lights.

On the upper line, troughs ranging from the weakest to the strongest bumps. On the second line, these are bumps that stand out. The mastery of these light bumps is very important, it is the basis of the textures, and will make it possible to manage all the simple cases, such as wood or matte plastic. Example of application on a simple object:

4. Reflections

The application of a reflection is done in a simple way, by applying diagonal strips of light of varying thicknesses, and following a few rules.

A trough or bump will create an offset at the reflection level (proportional to the height change). As for the shadows, there is no absolute, depending on the palette or the material represented, it is possible to lighten or not the area at the reflection level. It is also important not to have parallel light bands on faces that are not oriented in the same direction, as on this cube:

Concrete example of the application of a gold texture on our drawers:

Or, added reflections on our previous crate:

5. Dithering and granularity

Dithering consists in creating a new false color from a checkerboard or other regular pattern of two colors close enough to give an illusion of mixing. The closer the colours are, the stronger the illusion will be. The more the colours are contrasted, the stronger the granularity effect will be.

Dithering is basically used to obtain fake intermediate shades on limited palettes, but it is also very useful for making complex and rough textures.

Example of complex dithering separating 3 colors over a wide area.

The nature of the pattern totally changes the roughness aspect. Example of the application of a sandy rock on our drawers:

Or add grain to our crate:

6. The art of destruction

The more complex a texture is, the more it will combine fundamental techniques such as bumpiness, reflections or granularity. However, some materials need to go further, by cutting, slash or breaking the base support.

Cuts It works much like bump, but on a much finer surface. We are subject to the same rules, of which here is a summary image:

From the finest to the most pronounced, on the first line of the cuts, and on the second of the bumps. A concrete example on our crate:

Exercises

Since nothing beats practice to learn, here is a series of examples from the simplest to the most complicated.

For each exercise resolved, post your results.

Mastering tools

Add a strong bump on the text of this image, except the 'x' which must be a groove (the center must be dug more strongly than the rest of the 'x'):

Palette:

Add reflections on the image obtained between the two red lines shown below:

Now cut and break the letter 'e' as well as possible.

Add grain to the letter 'l'.

Finalize a sprite

Texturize/colorize this sprite:

Palette:

Add reflections on the inside of the doors to give the impression that there are windows.

Add damage (cuts etc) on the right side of the wardrobe.

Make a variant of this cabinet by redoing it in gold using the palette of the gold drawers example in the tutorial. Palette:

Do the same with the sandy rock. Palette:

Sample solutions

Here are some solutions by a talented friend :

Gif process

Introduction

In this tutorial, I will explain you how to use a couple techniques I used to improve Planet Centauri's sprites before implementing them into the game (or before animating them). Some of the rules shown here are very easy to use, and/or are purely  methodical; so even if you aren't very skilled, follow those simple guidelines to make your sprites cleaner.

Colors

A lot of basic mistakes will ruin the quality of your art. Thankfully, they're also generally quite easy to fix with some experience, and by paying attention.

Too many colors Pixel art is all about constraints. When two colors are very close, merge them into an intermediate one, so you see if it improves the result. Using a small palette will help you improving your skills much more easily, and will make creating sprites also easier. It also will make it easier to identify unwanted artifacts (i.e. misplaced pixels).

Gradients If you are constructing a palette with gradients, avoid at any cost independent gradients (i.e. only dimmed/lighted base colors). Use gradients that depends on each other. You can also try to use yellow-ish or cyan-ish saturated light colors, and blue-ish and purple-ish desaturated dark colors. However, avoid using an over-saturated or an under-saturated palette. This usually ends up bad and breaks contrasts. You should also use gradients with outspread tints to avoid washy color contrasts. Remember never to use more colors than necessary, and use gradients with contrasted brightness. Feel free to try using other generic palettes on your sprite to compare it with your palette so you can improve it. Neighbor colors Avoid as much as you can excessive contrasts between neighboring pixels. For example, a black line over a white background usually won't look natural. A line that fits the background color well gives a realistic volume effect.

This is as true for outlines, which has to fit with both the inner color and the umbrage of the surface.

NB: Obviously, this doesn't work with any graphic style.

Pillow shading

Pillow shading is a nasty effect that occurs when the light source comes from the front.

Avoid pillow shading, unless you really know what you're doing.

Lines and curves

Perfect line: A line that has a constant vertical and horizontal step.

Perfect curve: A curve made of perfect lines which step always depends on the other parts of the curve.

Dirty line: A line that has at least one sub-segment with more than one adjacent pixel on one end. As you may have noticed on the pictures above, dirty lines should be avoided. You should use as much perfect lines and curves as possible.

Clusters

A cluster is a group, a pack of connected pixels with the same color. Cluster shapes will greatly affect the final image. Bony and crude clusters will give a sketchy aspect. Round and straight lines are preferred so you get a precise, smooth and nice image.

Avoid lonely pixels. If one pixel is inside of a different color cluster without any adjacent pixel with the same color, remove it.

Dithering et texturing

Contrary to popular belief, dithering isn't as great as it seems. A lot of dithering between heavily contrasted colors will often give a dirty and noisy image. It is also a very bad idea to use dithering when animating a sprite, because keeping coherent dithering will be awfully hard. If you art style lets you do it, use texturing instead (the difference is that texturing does not induce color limitations). But don't forget, texturing means harder animation and worse clarity. Again, it's a matter of style. If you want a cartoon-ish look, do not use dithering nor texturing.

Antialiasing

Antialiasing a technique that reduces the staircase effect (aliasing) which is clearly visible on two lines between two contrasted surfaces.

Internal AA There are two use-cases for internal AA : Simply separating two surfaces, and using lines or curves cutting through two different surfaces. In the first case, you may just need to insert an intermediate color where aliasing is visible to reduce it (generally, when the curve abruptly changes).

In the second case, you may just need to add a small intermediate color cluster between every horizontal or vertical sub-segment. Its size directly depends on the sub-segment size.

External AA External AA suffers from an important restriction, unlike internal AA: The background color in a game will constantly change, so you need to have an effect that looks good on both dark and light backgrounds.

This rule is quite easy: You only apply the effect inside of the sprite. The end of an outline that neighbors with the background should never be modified.

In this image, the internal AA effect applied on the outer part of the sprite unveils some nasty artifacts, while external AA, even if it isn't as efficient, gives a great effect on any background type.