so I am officially confused!
according to this
color inversion in subtract mode IS normal thing.
yet in original Cin something else happens ....
may be Phyllis can replace our original red-green square images with full-color gradients + photo, so effect will be more natural? Or add this into new appendix .....
As suggested, I
included in the Manual (just checked into GIT) another set of
illustrations for the 30 Overlays using full-color gradient + photo. In
looking on the web for comparison and additional information, I hope it
is correct with the known guard problem with Subtract. In comparing to
the only 7 that are in HV 4.6.1, I found 2 other differences. See attached for "Divide" and "Min".