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

Overexposeure was Re:Pinhole gums

Hi Diana,

I think you have a couple of problems here. If the gelatin was drying as you brushed it on then it probably dried on the surface of the paper rather than in the paper. If this is true then it follows that the gum mix also dried on the gelatin rather than on/in the surface of the actual support. Add to this gross overexposure due to lower humidity and you have an immoveable image in gelatin hardened by dichromate..but I could be wrong...


David H

On Nov 29 2008, 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.

  • References: