9.5.2

872 • CHAPTER 18
THE SHADERS • 873
Overlay
If the Base channels’s color value is less than half of the maximum value, the Multiply blend mode is
used. If the color value is greater than or equal to half the maximum value, the Screen blend mode is
used. This shows patterns or colors of the Blend channel while preserving the shadows and highlights
of the Base channel.
Hard Light
If the Blend channel’s color value is less than half of the maximum value, the Multiply blend mode is
used. If the Blend channel’s color value is greater than or equal to half the maximum value, the Screen
blend mode is used. This mode is generally used to add highlights or shadows.
Soft Light
If the Blend channel’s color value is less than half the maximum value, the Burn blend mode is used. If
the Blend channel’s color value is greater than or equal to half the maximum value, the Dodge blend
mode is used. This mode is generally used to add soft highlights or shadows.
Dodge
The lightness values of the colors in the Blend channel lighten the colors of the Base channel, lightening
the image. Light colors produce the most lightening effect and black has no effect.
Burn
The lightness values of the colors of the Blend channel reduce the lightness of the Base channel,
darkening the image.
Darken
Only values of the Blend channel that are darker than the Base channel are mixed.
Lighten
Only values of the Blend channel that are lighter than the Base channel are mixed.
Add
The Blend channel is added to the Base channel.