Subtract and Divide
Subtract:
Subtracts brightness based on blend layer
brighter colors darken more
darker colors darken less
In the left example, the dark lines of the blend layer darken the least, ie. are the lightest on the base layer
In the right example, the black background of the blend layer doesn't change the base at all, while the lamp darkens the most
Divide:
Opposite of Subtract, brightens based on blend layer
darker colors brighten more
brighter colors brighten less