Corel Painter lets you manipulate the overall lighting in Thick Paint brushstrokes by using ambient lighting, adjusting shadows, and adding directional lights. These controls are global — they affect all Thick Paint brushstrokes on all layers.
An ambient light source is available for Thick Paint brushstrokes. You can adjust the brightness of the ambient light to lighten or darken the colors in the lit areas. You can also disable the ambient light source.
A brushstroke with ambient light (left) and without ambient light (right)
You can control how dark the shadows are in the brushstrokes. When you increase the shadow strength, the colors in the unlit, indented areas of the brushstroke become darker.
Shadow Strength values: low (left), high (right)
Setting the position and color of directional lights
You can adjust surface lighting by using preset (simple) lighting or custom lighting. With simple lighting, you can choose one of eight preset lights. With custom lighting, you can add more light sources, and you can move and delete light sources. The lighting sphere shows all possible surface angles and how the lights illuminate them. The light indicators on the sphere show the position of all light sources.
When you disable the Simple lighting option, the lighting sphere appears with a single light indicator. You can then add more light sources and change their position.
In addition, you can change the color of a light source. For example, you can have multiple colored lights interact with the depth to produce different texture effects. You should keep in mind that each light interacts with all Thick Paint brushstrokes, so be careful not to set up colored lights that clash with the colors in your composition or light sources that create unwanted shadows.
The Thick Paint brushstrokes above use light sources with different colors.