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:
http://www.pacifier.com/~kthayer/html/RGBseps.html
http://www.pacifier.com/~kthayer/html/CMYK.html
http://www.pacifier.com/~kthayer/html/tricolor.html
Katharine
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...
http://i31.photobucket.com/albums/c367/phritz/01-1.jpg?t=1234279590
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,
phritz
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