Re: Gum transfer

Sandy,
I assume this is for the developed image on plasitc to be transferred to
another support. Is a fiber based photo paper the way to go? Should the
drying be done under pressure? I guess I have to read some literature on
carbon double transfer. It always seemd so complicated I aways skipped that
chapter.
Marek

>From: Sandy King <sanking@CLEMSON.EDU>
>Reply-To: alt-photo-process-l@usask.ca
>To: alt-photo-process-l@usask.ca
>Subject: Re: Gum transfer
>Date: Mon, 17 Apr 2006 14:11:15 -0400
>
>Marek,
>
>Try the following and see what happens.
>
>Take a piece of photographic paper and fix it out and allow to dry. After
>it dries, soak it again in a alkaline solution of very hot water for 15
>minutes or so, then rinses briefly in warm fresh water.
>
>Squeegee the gum print on plastic to the emulsion side of the photo paper,
>leave under pressure for thirty minutes or so, then allow to dry. Drying
>may take several hours. The image should either stay on the plastic or
>transfer to the paper, or half and half which would be the worst case
>scenario. This is the protocol for double transfer carbon. May not work,
>but should be worth a try.
>
>Sandy
>
>
>
>
>>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 13:19:27 2006