Digital Light & Color

I had a few situations lately when easy access to channels and the ability to mix them would be of great use. I've done it 'by hand' - which is both cumbersome somewhat and non interactive. I have no idea, but I imagine that the R,G,B,H,S,V(L) channels are easily accessible to the PWP functions and there is also an excellent Monochrome Channel Mixer already. Would it be difficult to extend it with a choice of an output channel(s)? Cheers.

1. Could you describe roughly what you do by hand?

2. Perhaps this thread about using Hues curves is a partial step toward your goal:
http://www.dl-c.com/board/viewtopic.php?f=4&t=317

3. There is a channel mixer in the free program Raw Therapee. Despite the name of the program, RT will open a TIF file, too, and save a TIF file for further work in PWP.