This effect uses the image’s luminance (grayscale image) to remap it to a color gradient. Excellent for reproducing heat- or night vision, or to act as color grading.
Black pixels are mapped to the left side of the gradient, white to the right. Values in between are mapped accordingly.
The effect enables you to apply the colorization through Linear, Multiply, Additive and Screen blending.
This example shows the effect at full strength using Linear blending.
Gradient used (included in samples packages):