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

Re: Pinhole gums

Diana, do you have a way of reading the humidity in your workspace?
It sounds, even with the humidifier going, that your humidity was
lower than customary, as evidenced by the problems with the gum
coating setting up too fast. However, there's a puzzlement here,
because as David said, the lower humidity should mean longer exposure
times, but it sounds from your description that you were experiencing
overexposure rather than underexposure at your usual times. I hate
it when things don't make sense. Another possible variable: I
discovered last winter when working in an unusually cold space that
the gum process doesn't work well below a certain temperature, I'd
say 48-50 F. But if you were working inside in a room that's
reasonably temperature-controlled, that should be a problem.

As long as the gelatine didn't set up before it soaked into the paper
(agreeing with David again) I don't think sizing was your problem
here; I think it's something about the environment/humidity,
although it's not behaving as I would expect from my experience and
from industry research related to gum and humidity. So that's a
little baffling.


On Nov 29, 2008, at 11:51 AM, Diana Bloomfield wrote:

Hi David,

Thanks. I didn't think the gelatine was cooling, but possibly that
was happening. The humidity had definitely dropped-- very dry cold
weather. I usually use a humidifier before coating the gum/pigment/
dichromate mix, and I used the same exposure times as always. So
what's happening-- when I coat the paper (inside), doing everything
I've been doing-- the coating seems to be drying really fast, as I
brush-- even though I'm using a humidifier. I use the same
exposure times that have been successful for me in the past. So
when I take out the paper, after exposure, I can see the faint
outline of the image-- but after soaking it in water, forever,
nothing ever happens. If I brush away the pigment, that helps--
but basically the image just sits there undeveloped for the most
part. So should I be increasing my exposure time because of the
cold, or is my problem in the sizing? When I was using all this
great paper I'd sized over the summer (when it was hot and humid),
I had no problems, so I'm thinking my problems are at the sizing
stage. ?

On Nov 29, 2008, at 2:33 PM, davidhatton@totalise.co.uk wrote:

Hi Diana,

You have to be a little careful that the gelatine doesn't cool of
before it soaks into the paper. Also if the humidity drops due to
the cold, exposure times will probably lengthen. What problems are
you having??

David H

On Nov 29 2008, Diana Bloomfield wrote:

Thanks for posting those, Marek. That is brave of you to post the
originals, too. I like the rich red of those. Almost of my gum
prints have been made with either pinhole, zone plate, or a toy
camera. I made my first couple of gum prints from a lens-based
camera only last week. I couldn't believe how much easier it was to
register from a sharp, well-defined negative. I had no idea.

I do have a related question maybe you or someone else can answer. I
always size my paper, and dry it, outside, and I sized a batch last
week when it was unusually cold here. I had my gelatin and hardener
in one of those electric pots that keeps warm, but I still had to
coat fairly quickly. I've had a lot of gum-printing trouble with
that paper ever since. So is that a known problem-- coating gum, or
sizing, or hanging it up to dry-- in relatively cold weather? Or
should that not make any difference?

On Nov 29, 2008, at 12:38 PM, Marek Matusz wrote:

> Wow
> It has been so quiet on the list that I decided to post some
> pictures printed over the holidays. They are gum prints made from
> pinhole photographs. I have done the worst thing by posting the
> originals as well, but maybe it will create some discussion
> Marek
> http://picasaweb.google.com/marekmatusz1/
> TricolorGumBichromatePinholePhotographs#
> Get more done, have more fun, and stay more connected with Windows
> Mobile®. See how.

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