Brightness applies the brightness of the blending layer to the base layer while preserving the base layer’s hue and saturation. This lets you change the light and dark values of an illustration without changing its colors.
The Math
Brightness takes the brightness from the blending layer and combines it with the hue and saturation of the base layer. The top layer controls how light or dark the result is, while the bottom layer controls what color it remains.
Think of it as separating the lighting from the color. The top layer controls the light and dark values, while the base layer keeps its original colors.
Core Rules of Brightness
Brightness changes: The light and dark values come from the blending layer.
Hue stays: The base layer keeps its original color family.
Saturation stays: The intensity of the base colors remains intact.
Black darkens: Painting with black makes the underlying colors darker without changing their hue or saturation.
White brightens: Painting with white makes the underlying colors brighter while preserving their hue and saturation.
When to Use It
Value adjustments: Change the lighting and value structure of an illustration without repainting its colors.
Coloring grayscale artwork: Use a grayscale shading layer to control the brightness of colored artwork while keeping its established hues.
Lighting changes: Experiment with highlights and shadows separately from the color scheme of the artwork.