Re: Gum transfer

Here's Marek's gum transfer; you've impressed me again.

http://www.pacifier.com/~kthayer/html/Marek2.html

On Apr 17, 2006, at 10:44 AM, Marek Matusz wrote:

> There were a lot of interesting posts this weekend and I am going
> thorugh them now. I have done a few more gum transfer experiments.
> Here are some observations and issues.
>
> When exposing a gum layer through the substrate (glass, polyester,
> etc). This is "expose through the bottom mode" heavy pigment
> concentration is OK, coating imperfections are not that critical as
> the air bulles rise to the top, streaks in coating are also on the
> top. A thin image layer that adheres well to the substrate after
> development shows relatively few imperfections and looks
> suprizingly good. I have not done much more on that as I am waiting
> for a sunny weekend where I can experiment with some gum on glass.
>
> Gum Transfer.
> Here is how I approached it. I though it would be very difficult to
> transfer actual developed and hardened gum image by means of
> softening it and transferring to the paper. Instead a process
> similar to a single carbon transfer was appealing to me. Here is
> what happened.
>
> I coated a few sheets of plyester with same emulsion (gum, lamp
> black, ammonium dichromate) that I used in my previous experiments
> (expose through the back). This time I exposed in a traditional way
> from the top. I will call it the gum tissue. This should form a
> hardened image on top of the gum layer with unexposed and soluble
> gum on the bottom. We know what happens when you put this image in
> water. Everything just slides off.
> OK, I then placed the gum tissue on top of gelatine sized paper,
> made a sanwich let it sit for a while and placed in warm water to
> start dissoliving unexposed gum so that the tissue and the support
> could be separated. Then just wait until the water dissolves the
> rest of the unexposed gum revealing the image.
>
> Some of the difficulties. Even a very short water immersion (cold
> or warm) of the exposed tissue to remove dichromate softens and
> starts dissolving the gum, no usable image can be transferred.
>
> The tissue image needs to have decent mechanical strength for the
> transfer. It needs to be thicker, which suggest less pigment,
> thicker coating.
>
> All the air bubbles and imperfection are on top, where the image is
> formed. There are all visible in the final image. Rollesrs and
> other means of smooting out the coat do not work with thick layers.
>
> My impression is that because the dichromate is present in the
> transfer process for about 30 minuts, before tissue is pulled away,
> I am getting a dark reaction, or something, as I am not getting
> very clean highlights. My exposure might be too long, or dichromate
> concentration too high as well.
>
> My negatives are for Pd printing, not for carbon. Just a minor issue.
>
> As Sandy noted I could print in carbon, but it is such a finicky
> process that requires a very precise time and temparature control..
> I am still hoping that an easy way of transfer could be found with
> gum, or perhaps gelatine/gum mix as I am thinking now.
>
> I have one picture from this trials and perhaps Katharine would be
> so kind to add it to her site.
>
> Marek, Houston
>
>
>
Received on Mon Apr 17 12:08:40 2006