From: Cactus Cowboy (cactus@tritel.net)
Date: 09/09/02-12:54:54 PM Z
Welcome to the list!
> Hi All!
>
> I'm new to this list, and also to gum bichromate printing. I'm coming to
> this sideways from a background in painting and drawing, but for the
> past 12 years I have been working increasingly with digital images. The
> big problem to me is how to get the images out of the machine, and this
> group will understand when I say that I wanted a print and not a
> printout. Years ago I had a friend who was a gummist and so I eventually
> came around to thinking that this might be a very good solution, one
> that I could control well and that would also give a unique product as
> opposed to a set of reproductions. It seemed to combine the best of all
> worlds and would even let me experiment with newer pigments and
> additives (such as mica). So, I have made a negative and I have my
> chemicals, Fall is almost here and I'm ready to start.
>
> One worry I still have is about handling the waste. I've spent a few
> days reading through the archive ... it's huge! ... but I'm still not
> sure what I should do with the wash water, according to current
> thinking. Do you have some advice on disposing of it? Do you have to be
> equally as careful with the third wash as with the first, in terms of
> disposal? I will have a fairly decent space set up (about 9'x 26') in
> the basement with water and sinks for doing the messy parts, but I won't
> have leftover developer and such because I'm not a photographer.
My cyanotype and gum wash water goes down the drain, and into a septic
system. It's so heavily diluted that it will never cause a problem.
> Some more question: There are some odds and ends collected around the
> house I am wondering if I can use in my new lair. There is an old
> refrigerator that was in the house when we bought it. It's sitting
> unplugged in the basement and I could move it into my darkroom if I had
> a use for it. Is there a use for refrigeration?
The refrigerator would be useful for film storage, and keeping cold beer at
hand.
> My husband just bought a new compressor. I have several nice airbrushes
> from my days in commercial art. What is the current thinking about
> airbrushing emulsion onto the substrate? I read in the archive about
> applying a dichromate layer with a brush and then airbrushing the
> pigment on. Does this work?
I would not recommend air-brushing emulsions. Having chemicals or pigments
air-borne in a form that's easily inhaled seems unwise. I've never applied
dichromate and pigment seperately. It's my understanding that they need to
be well mixed before application.
> I noticed a product in the catalog called a Pfaff paper safe. Could this
> be used to store paper prepared for gum prints, if I wanted to prepare
> several at a time?
Yes. Use your prepared paper within an hour or two if possible. It does
not have a long shelf life.
> Back in the dinosaur days I ran the photostat camera at an drafting
> supply house, and we made very nice big negatives for the silk screen
> guys. Are these cameras still around? Does anyone out there use
> negatives made this way? There were a lot of those cameras around at one
> time. Are they commonly for sale second-hand these days?
With the advent of digital, these cameras are readily available and would
most likely be bought for little money. I was given a 14" Artar lens years
ago from a printer who no longer had use for it. I had it mounted in a
Copal shutter. It's a fine lens and works nicely on my 4x5 field camera. I
use a 4x5 englarger to make my enlarged negatives on lith film. I see no
reason why a big graphic arts camera couldn't be used to do the job. With
the refrigerator and possibly a large camera, you must have a big darkroom!
> About grinding the pigments into the emulsion... it seems to me that
> basically what you are doing is just preparing watercolors by hand
> (which I am not opposed to). I even have a collection of dry pigments
> from the days when I felt compelled to do everything from scratch. My
> question is, does this really get you anywhere? Watercolorists grind
> their own if they feel that commercially prepared products don't give
> them exactly the quality they want, but for this type of printing it
> seems to me that you wouldn't be controlling the pigments as precisely,
> so I am wondering if there is any real benefit. The only advantage that
> I can see would be to increase the homogeneity of the dispersion but is
> this a problem often encountered?
I prefer using dry pigments, mixed into gum in 100~200ml batches. Using a
mortar and pestle, I mix pigment into a small quantity of gum, slowly adding
gum as I mix. If your stock solution of pigment/gum sits for a while,
you'll need to stir it up with a stiff bristle brush to evenly disperse the
pigment before using.
Best regards,
Dave in Wyoming
> Thanks!!
> Marcie
>
>
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