|When I was printing in this process I used 1:3 gum and 1:12 bleach for 2 minutes, I found that the most flexibility was in the bleaching and the kind of bleach. For whatever reason the "splash free" bleach worked the best. |
On Oct 31, 2009, at 2:33 PM, phritz phantom wrote:
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:
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
It doesn't matter, I'll be testing
Original Message -----
Saturday, October 31, 2009 12:42 AM
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
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
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