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Re: Gumoil


Jim help me to get succes in this process.  I am just thankfuf to him. The choice of the paper is a great part of the succes , lana aquarelle and Fabriano give great result.  There is o pigment in your coat so exposure will  be shorter.  and the exposre will be different as you must use a contrastier negative(positive) compare to your gum negative

christian nze

Give it a try, Paul, and see what happens! I don't know the answer, so I am not trying to bait you ;) And I do not think that it is 3:1....1 pt of gum, mixed 1:1 by vol, plus 2 pts gum mixed 1 pt gum(powder) to 2 pts H20, plus 1 pt saturated Potassium Dich. This serves as a good starting point, and is what I use. Depending on your results, you can coat your surface, after it has dried, with a second coat. Your exposure is going to be longer...4.5-5 under Black light or sun. Do a few test prints as it can be very tricky!

On Fri, Oct 30, 2009 at 10:45 PM, Paul Viapiano <viapiano@pacbell.net> wrote:
I know that Karl Koenig uses a 3:1 gum/pot dichromate ratio for printing the positive, but I was wondering if anything would be amiss should I use my usual 1:1 (sans pigment, of course) since my gum negs are tuned to that already and I have a known exposure factor...
3:1 would make for a more contrasty gum deposit, I would guess but I'd have to expose longer than my 1:1 mix, right?
Someone, maybe Katherine (?) had a rule of thumb for exposure times with differing ratios/amounts of dichromate...?

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