U of S | Mailing List Archive | alt-photo-process-l | Re: color printing for dummies

Re: color printing for dummies

watch out this

or this

At 16:51 10/02/2009, you wrote:
i really need some help here. i searched the internet for hours yesterday, to no avail. could someone recommend me a good tutorial for color printing for alternative processes (esp. gum printing)?
i dabbled in color gum printing for the first time some days ago. i tried rgb-separations from photoshop and exposed three layers: one for cadmium-yellow, cadmium red and payne's grey each (i know not the best choice).
i think the outcome was somewhat successful. at least the green on the chest looks pretty much like in the original. so i can't be that far off...

ok, since i really have no idea about color printing, at first i thought, i could just invert the image, split channels (getting three images.one labelled r, one g, one b), and use the r-one for the red layer etc....
looking at the negs, i managed to find out (of course the red parts in the original images have to be the thinnest areas in the neg for the red emulsion layer) that i have to use the opposite colours: the r-channel for the yellow emulsion....
now i wanted to play around a little with other pics, curves and cmyk separations... now cmyk separations is really where my knowledge comes to an end. do i have to use the opposite colours with cmyk too after inverting and splitting channels?
the k-negative looks like it should be used with the black pigment emulsion... and the others?

i know this is very basic stuff and i'm a little embarrassed that i can't find it out by myself. but i really wasn't able to find a suitable tutorial for that. all that negative, opposite colours and inverting makes me dizzy.
how do i find out which separation is the suitable negative for which pigment emulsion?

thanks for the help,

Chris Nze