U of S | Mailing List Archive | alt-photo-process-l | Re: gum beginnings

Re: gum beginnings

Hi Laura,

To attempt to answer your questions

If the print is a little light you may need more pigment - also I find that
the first few coats tend to be a little on the flat side - the contrast and
depth builds up with multiple coats. Perhaps start by doing multiple coats,
if you still think your prints are too light consider increasing pigment
concentration. What also helps is to understand more about your pigments.
The website handprint (Katherine Thayer has  referred to it many times in
posts) provides lots of useful information about transparent and opaque
pigments. For example for my first coat I will often use a more  opaque
pigment to provide a good base for subsequent coats.

The clearing stage happens once you have printed your last coat and the
paper should be dry before adding to the bath.

Sizing - I can't comment on glyoxal as I use formalin, but I would normally
add the gelatin to cold water and then increase the temperature to around
40c when I brush on. I add  the  formalin just before I brush the size on
the paper and do  just one coat.

I have  some more information at http://www.gumphoto.co.uk

Hope  this helps


On 18/11/06 19:06, "Laura Valentino" <laura@this.is> wrote:

> Hi everyone, I finally got set up with a workshop space, gathered my
> materials and arranged my schedule to begin my gum printing...so
> yesterday and today I jumped right in and started printing. My results
> were a little on the faded side...I increased the exposure time, which
> helped a bit, but increasing it even more didn't really help more. Maybe
> I just need more pigment? Or more layers?
> One question I have is about the potassium metabisulfate (it came in a
> kit, no instructions), which I had thought was a fixing agent, but turns
> out is a clearing agent. Does that mean I develop the print in that
> solution? What I actually did, was develop in plain water, then put it
> in the clearing solution bath. The color seemed to just slide off when
> I put it in the clearing bath!
> Another question I have is about sizing. I was using paper that I had
> sized myself years ago by dipping in gelatin hardened with formalin. Now
> I want to size some new paper with a smoother surface (the old paper was
> cold pressed). I think I will use the brush on method. What I have is
> 250 Bloom Gelatin (a powder) and Glyoxal solution. Do I just mix the
> gelatin in cold water, or does it have to be heated? Can I mix a big
> batch and just add glyoxal to small amounts as needed, or do I only mix
> what I'm going to use at the time? And lastly, is the paper only sized
> once, or do you have to size again between colors?
> Hope that's not too many questions. Links to websites that explain this
> better would also be appreciated. Thanks so much!
> Best regards,
> Laura