U of S | Mailing List Archive | alt-photo-process-l | Re: Gumoil

Re: Gumoil

Plain chlorine bleach
----- Original Message -----
Sent: Saturday, October 31, 2009 11:33 AM
Subject: Re: Gumoil

regarding gumoil:
if i remember corrctly (it's been sometime since i did the reading about gumoil) the process uses bleach, i think karl koenig says "ordinary household bleach". since american and european bleaches are most likely different or at least the brand names are. what's the chemical in the "household bleach" that is the one used here? or will any kind of acid (anything with a low ph) work?

most people will already know this, but there is a video tutoral from karl koenig online:

Paul Viapiano schrieb:
000d01ca5a54$99e38d20$7000a8c0@dell4600 type="cite">
Thanks, Christian & Jim...
In a Camera Arts article, Karl mentions a more contrasty positive but more washed looking out as well. I didn't get what he was after there.
I experimented with my normal gum neg inversed to a positive...but was wondering if anyone had a suggested DR.
It doesn't matter, I'll be testing anyway.
----- Original Message -----
Sent: Saturday, October 31, 2009 12:42 AM
Subject: 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...?

  • References:
    • Re: Gumoil
      • From: cnze@club-internet.fr
    • Re: Gumoil
      • From: Paul Viapiano <viapiano@pacbell.net>
    • Re: Gumoil
      • From: phritz phantom <phritz-phantom@web.de>