Re: gum printing

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From: Henry Rattle (henry.rattle@ntlworld.com)
Date: 02/26/03-02:44:57 PM Z


Since it's time us lurking gummists came out of the woodwork, count me in,
too. I first came across a copy of Keepers of Light in the Photographers
Gallery in London in about 1980-82, and made a few gum prints a year or so
later. In 1984 that even included a three-colour gum (just one!), starting
from a slide which was "printed" onto film through red, green and blue
filters to make three 5x4 negatives, subsequently gum-printed with alizarin
crimson, monastral blue and cadmium yellow. A small print, but I was pleased
with it - and for a half-plate postal circle it was the right size. However
the labour of making and printing the tricolour negatives was just too much
for someone with a day job. My best print of that time was a little portrait
made with two printings of indian red - if you've seen the Demachy in KOL
you'll know why I wanted to try that.

These days I do mostly four-colour gums, relying on Photoshop separations
and usually starting with cyanotype as the C. Then alizarin crimson,
permanent yellow and Payne's grey for the MYK. Sometimes substitute burnt
sienna for the magenta, and yellow ochre for the yellow. Overall aim is for
"real" colours, but mellow. Yellow ochre over cyanotype makes very nice
stonework, and burnt sienna over cyanotype is great for anything rusty!

Paper is usually Bockingford (what Judy calls "tree bark" but I like it)
with no shortage of sharp detail even so. Preshrunk at about 90 degrees
(Centigrade) and then soaked twice in food-grade gelatine and once in dilute
formaldehyde (with all the windows open). Potassium dichromate, saturated
solution (on the KISS principle), though my tests of saturated Potassium
against saturated Ammonium dichromate bear out the assertion that the
ammonium gives a much longer tonal scale (also in my tests the ammonium
didn't clear pigment as well). Don't use a clearing bath as little or no
visible stain remains. The higher contrast of the Pot Dichro seems to suit
the colour separation prints best.

Incidentally I use Pete Marshall's smaller (about 12x12 inches) printing
frame - it makes ingenious use of a standard office four-hole punch for
registration, and is very reliable especially if the negatives are printed
with registration marks for a final check of alignment.

This list (and P-F) remains a constant source of inspiration and interest.
Thanks, Gord, and everyone who shares so freely.

Of course there are a million things still to try - now when do I retire?

Henry

On 26/2/03 2:41 PM, "Dave Rose" <cactuscowboy@attbi.com> wrote:

> "Gum is the monarch of printing processes; they crowned it long ago. Since
> the memory of man runneth not to the contrary, it has held undisputed sway
> as the aristocrat of photography."
>
> Photographic Control Processes by Franklin I. Jordan, F.R.P.S., 1937 Galleon
> Publishers, Inc.
>
> 66 years later, I'd have to agree with Mr. Jordan!
>
> Best regards,
> Dave Rose
> Cactus Cowboy
> Big Wonderful Wyoming
> cactuscowboy@attbi.com
>
>


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