Subtractive Color Mixing in Photoshop using the Multiply, Difference and Exclusion Blend Modes

I expected the multiply blend mode to properly combine CMY separations into full color images.

It does.

I was surprised to see how well the difference and exclusion blend modes accomplished the same task. You may assume it's because they are subtractive in nature, and so should be expected to perform subtractive color mixing, but in fact they mix pairs of colors in surprising and unnatural ways.

More on blend modes.