hard light mode|
Another combination of screen and multiply mode, depending on the blend color
(the "opposite" of overlay mode - NOT the "opposite" of soft light mode! -
in fact the names of overlay mode and hard light mode should be swapped to be more logical).
||2ab (for b < ½)|
|1 - 2 * (1 - a) * (1 - b) (else)|
There is a separate formula for bright and for dark blend colors,
so there is a discontinuance for b = ½ (diagram 1 can be sparated into two parts).