Re: Tricolor Gum Bichromate materials

Virginia Boehm (gini@ix.netcom.com)
Mon, 27 Feb 1995 18:23:53 -0800

You wrote:

>
>In-Reply-To: <Pine.3.89.9502270952.E12661-0100000@m-net.arbornet.org>
>Tricolour gums.
>
>It is fairly easy to register with gum prints as you can see the
previous
>image. You just need to use a couple of pins in the edges of the final
>negs and the paper.
>You do not need to register in any of the film stages. I found it easy
to
>contact print slides onto panchromatic 35mm film to give a low contrast
>positive (make sure you give a full exposure at this stage). I modified
>an old contact printing frame with a couple of pins to hold a strip of
>film and taped the slide by its edges to the glass so there were no
>location problems in the dark. This was exposed under an enlarger with
a
>suitable filters - as used for additive colour printing. Then make
>enlargements on a cheap ortho film. I wrote to Agfa and they gave me a
>few small packs of 8x10 and A4 film to experiment with! Kodak didn't.
You
>can use lith film so long as you do not use a lith developer - I used a
>dilute universal developer.
>Most registration problems are caused by the paper changing size during
>multiple processing - it helps if you soak the paper in warm water and
>dry it before starting the print.
>
>Peter
>petermarshall@cix.compulink.co.uk
>
>
>

Yes. This is very close to what I'm doing. It doesn't just help to
soak the paper, its essential if any porous rag content paper is used.
Soak it, then size it, then size it again on the other side to keep it
from curling too much after each coat - that can create registration
problem too.

But I agree - registration isn't a huge problem if you make sure the
negatives are all the same size to begin with. Tape works just fine.

Gini