Re: RE:Gum printing ?

Robert,
     So many questions, so little time (heading off to Charleston tomorrow
again) but I'm sure others will chime in.
     A blue I have found to be a wonderful process blue (cyan) is Winsor
Blue Green Shade. Or use a Thalo Blue. Very powerful. Ultramarine is
kinda weak and stinky. Others I'm sure will beg to differ. But in looking
at your prints, I don't see enough of a blue layer, and too much red. You
may want to switch from anthraquinoid red to a more magenta, too.
     I use a quinacridone magenta or q pink or whatever for the magenta
tone. The yellow is gamboge or cad yellow or others.
     The exciting thing for me is when you do the yellow layer first, you
don't see much. Then the red goes on there and it looks pretty good, but
not great. Then the blue gets exposed, and VOILA, when you spray develop
all of a sudden you see all the colors ring true. It is quite exciting,
leaving the blue til last. And weirdly, the blue will make reds appear, by
contrast and such, I suppose; for instance, I had a pepsi bottle in one
image and the red on the label didn't differentiate/appear until the blue
was exposed and developed.
     Am I reading correctly that you are doing 3 coats of gum and then 6
coats MORE? I get fully tonal gums in three layers, hence I would say
increase your pigment unless you like printing that many layers. Some do.
     I print yellow first. I tape my registration pins to the glass and
punch holes in my paper. (Lately, tho, with this last batch of paper, when
I get to the blue layer I have to register by sight. I'm having a hell of a
time with this batch). Otherwise I always just kept putting the paper back
onto the registration pins the 3 times and never worried about anything.
You are right about the blue layer making registration easy if done first.
Sam told me, since I don't do a cyano layer or blue layer first, to print a
pale blue layer, and then do the 3 on top, so in other words do 4 layers to
be able to register more easily. That was late breaking news from him :)
when I kept having probs with this registration of this batch of paper.
      The easiest way to balance your color is adjust your pigment load,
IMHO. I doubled all pigments to increase my contrast of my prints and to
increase my saturation, per faculty request :). I still expose all at 4
minutes, but have taken to exposing the blue at 5 minutes, or a tad longer
because it's darker and seems to hold back more light. However, tonight I
didn't and it worked fine. In other words, all my layers are mostly exposed
the same, every neg. But this is because I have applied the same curve to
all.
     I am very unscientific with the pigment load: I mix stock solutions of
a whole tube of watercolor paint into a 50ml bottle of gum. That is my
stock. I never have problems with streaking by having the pigment already
"watered down" with gum. I mix a 2 tsp of this stock to 2 tsp gum to 3 tsp
water to 1 tsp am di saturated. 8 tsp gives me enough to coat 2-3 11x17's
and 6 8x10's at once.
     Happy gumming!
Chris
PS Uh oh, you are printing the yellow layer with the blue neg, the red with
the green neg, and the blue with the red neg aren't you? Or are these BW
negs? In which case, some of what I said does not apply, as you are just
"simulating" color instead of printing actual color...
PPS if your neg is perfect for platinum printing, they may be contrasty for
gum...

> I am making digital 8x10 negatives which print in platinum/palladium
between
> 2minutes to three. Three coats of gum 1 1/2 minutes to 2minutes, six coats
> gun 1 minute each coat. I am mixing 5cm gum to 5cm potassium dichromate
with
> 1 gram of water color pigment. I am using Daniel Smith: Antraquinoid Red,
> Cadmium medium yellow and Windsor & Newton French Ultramarine. The red and
> Yellow seem to work well and l looking for a better blue.
>
> One of the things which I am unsure about is the order of the layers to
make
> a color print. When I use blue for the first coat I am able to register my
> negative with out trouble. When I use yellow for the first layer it is
much
> harder to see the negative come into registration, but I achieved the best
> color by using Y, M then B negatives.
>
> I am unsure how to fine tune the color balance. More time for one color or
> more pigment? Since I am using Red, Yellow and Blue to make a color print
> would this be the same as traditional silver additive color printing.
>
> I will scan several prints and post them to phto.net so that you may have
a
> better idea how to give me direction. The nude negatives where on (cheap
> transparency film which ran during exposure)
> http://www.photo.net/photodb/photo?photo_id=2269073
>
> http://www.photo.net/photodb/photo?photo_id=2269086
> Best Regards,
> Robert Cockrell
>
>
>
>
>
Received on Wed Apr 7 21:52:39 2004