"Duplicate layer, invert bottom layer and cut all blacks and whites out
of (transparent) top layer (of course, if there's a range of greys it
gets more complicated)."
it's evident that this is the problem : i don't know about Rich's photo
but the sample i use here have various flavors of blacks'. If it is not
a simple Color2alpha should work to delete blacks and just add a white
layer below :)
i guess this is not the case :)
Rich : Try Gmic Toolbox>Colors>Replace color select black as original
and white as dest and play with smoothness. Is that good ?
!! It's not working exactly the same as Gimp's replace color!!
find gmic here : http://gmic.sourceforge.net/
this is a external filter addons with so many possibilities :)
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