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rgb-sub color_1 color ...procedure
rgb8-sub color_1 color ...procedure
hsl-sub color_1 color ...procedure

Subtract zero or more colors from color_1, similar to the "subtract" layer blend mode in image editing software.

The result type and color space used depends on the procedure. The result will have the same alpha as color_1. The alphas of the other colors determine how much effect they have.