Re: Gum Separations Using Indexed Color
Michael Koch-Schulte wrote:
Thanks Keith,
I'm in the middle of this project at the moment (Xmas is taking up a lot
more time with the kids out of school). I'm currently trying to output the
negatives for the various colours I want to use. These ideas formed over
the last few months. I've been doing a lot of painting lately, something
new for me. I've been studying a lot of "colour theory", colour mixing and
paint palette layout, etc., noting the differences between translucent,
semi-translucent and opaque pigments. I quickly realised how this could be
useful to expand the colour range in gum. [I recommend that anyone
contemplating gum printing take at least an introductory course in
painting and with a focus on colour selection or if you have to do
self-study like me. This will give you a certain amount of knowledge in
pigment use, you will learn "colour index names" and the properties of
various pigments, hopefully.]
The idea of using a limit colour palette in a painting is what first
trigger the notion of using six to ten colours rather than three or four
as is common in gum printing. What is known as a "split primary" palette
has a painter set up two yellows (one warm and one cool), two blues (one
warm and one cool) and two reds (one warm and one cool). What I mean by
"warm" and "cool" is that the colour are biased slightly toward their
adjacent colours, therefore the first yellow is bias toward orange, the
second yellow is biased toward green, the same goes for the red and blue.
One red bias toward violet the other toward orange, one blue bias toward
violet the other toward green. It's somewhat similar in concept to what an
Epson printer does with it's inks -- but not exactly.
My other area of study has been concerning what silk screen shops and high
end print shops print multi-coloured material by using "index" color. This
is a somewhat subjective process which involves selecting dominant colours
in the original work and creating dithered plates or negatives which blend
solid opaque colours to recreate the original work.
Some years ago I made some gums selecting colors with photoshop and then
printing those negatives with opaque or semi-opaque colors. Like you, my
process was to study first the main colors in the original picture and then
selecting the most appropriate ones. When printing, the reconstruction
becomes a very pleasing mental exercise because you can use colours which
are different from the original though the look of the final print is what I
would define "likely".
My prints are posted in www.grupponamias.com, going through authors>Alberto
Novo>Venetian gums
There is also a brief description of this process under "articles"
Alberto
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