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

Re: color printing for dummies

Hi phritz,
First, I'd say your blue (payne's grey) is too weak to balance your red and yellow; I'd recommend a more definite blue (pthalo, prussian, ultramarine or indanthrone) or a less definite red and yellow (that would give you a softer, more unsaturated color palette with the payne's grey. Yellow ochre and burnt umber can work well with payne's grey for that purpose).

Then, which color to print with which separation: cyan (blue) with the red separation, magenta (red) with the green separation, and yellow with the blue separation. That's if you create the RGB>CMY separations by inverting the channels individually. If you use the "multichannel" method described in James, the separations come out named CMY and you use them straightforwardly. With CMYK it's straightforward, use the separations as named.

For more detailed information:



On Feb 10, 2009, at 7:51 AM, phritz phantom 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,