Chapter 3: Outlines, colors, and lighting
Outlines
The outline (or lack of one) can change the look of your drawing dramatically. Careful use of color and highlighting on your buildings and objects makes them stand out more and gives them a more polished look. Black outlines help distinguish objects from the background, but can make the art appear more cartoonish. That may be your desired effect, but highlights can help create additional realism by simulating light sources.
3.1: Different types of outline.
Choosing the type of outline is the point you decide on the style you are shooting for. Black outlines separate the subject from the background, but should be combined with bright, saturated colors. Using a darker version of the base color on the outline can help them blend into the art while still defining shape. Some edges can be highlighted to help sell the lighting even more.
Colors
Using and selecting the correct colors to use for your isometric pixel art is one of the more important aspects of the overall work. One of the notable features of pixel art is the strategic use of color, especially as the art gets smaller.
Shading your work can mean more than simply darkening or lightening your main color. The hues and colors chosen determine the look and feel if your scene. Imagine your building or scene as it would look right in front of you. Whether it's bright plastic style, mid-tone natural colours, or even monochrome, it's entirely up to you.
Lighting
Unless you want all your pixel art to look flat, you will need to consider lighting. Color ties closely with lighting, as presenting the illusion of a light source is simply a matter of using lighter and darker color values. Most pieces use a single light source for simplicity, but if you are feeling adventurous and know what you're doing, you can try more than one.
3.2: A scene lit from the top-left.
To incorporate lighting, you first need to choose a light source. Most of the time, this will be the top left or top right of your drawing. Since this is isometric art, you do not need to worry about the light spreading away from the source, as there is no real perspective. All objects in your scene should be lit from exactly the same direction.