There are add and subtract blending options hidden somewhere.
In the 'apply image' and 'calculations' commands. Just reading about this in the help. Might do the job somehow. Or not.
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_Felix 's school of dance and occult sciences,
Fri 17 Apr 2009, 19:17,
archived)
I tried them, doesn't seem to work.
STUPID PHOTOSHOP!!!
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Jeru War and Piss,
Fri 17 Apr 2009, 19:19,
archived)
think i get what you're after now
I'll have a go and see if I can work it out
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Bloop Fri 16 Jul, 22:10,
Fri 17 Apr 2009, 19:23,
archived)
Ahhh it's called difference masking when you do it for video, that's helped finding a lot of tutorial links.
(
Jeru War and Piss,
Fri 17 Apr 2009, 19:44,
archived)