unmultiply plugin

[Herbert123]

I can't seem to get this 8bf plugin working - 32/64 bit versions: neither works. Can someone else check, just in case?

http://www.ayatoweb.com/download/down04.html

Very handy plugin to get rid of a black background, including alpha channel. I use this every once in a while to remove black.

[bkh]

Doesn't work on OS X either (the OS X version is 32 bit only). This is the first plugin I've tried for which PL actually reports a crash during startup.

Otoh., as far as one can guess from the sample image, this should be doable via a PL action as well (but it would be good to have a genuine before/after sample with transparency).

Cheers

Burkhard.

[jdcooke2012]

Hello,

I think if I were to make an "action" for this process, say separating fireworks from a black background, I'd use the "Change Channels" function.

- Open the fireworks image and duplicate it three times.
- On the top layer, Use the "Tools>Change Channels" function to swap the Green channel with Transparency, then the Blue channel with Transparency
- Next layer down, swap Red channel and the Blue channel each with Transparency
- Next layer down, the same thing to channels Red and Green.

You should now have three layers, one Red, one Green and one Blue, each on Transparency. (an action will do this in a split second)

Merge these three layers and you have "un-multiply" - You then add this to your new background using "normal" or "screen" blend mode (or "linear dodge", if you're working in linear gamma)

take care