Re: Clearing Gum/Carbon

Hans Nohlberg (chiahans@tripnet.se)
Tue, 16 Jan 1996 23:57:40 +0200

>
>>Thanks for describing your working procedures. Sounds like you have
>>developed a very efficient way of making carbons which should have
>>the same surface and dimensional characteristics of those made
>>in the traditional way.
>
>I hope to be able to verify that myself someday. The sample print that was
>sent to me by Archival Color Co. back in the early 1980s was definitely
>inferior to the so-called traditional method. No relief and there is some
>sort of artificial softness to it.

Is this a polite request to get a sample to your collection?:>)) We will
show our work (carbons and gumbis) in Boston in April/May this year,
welcome to see the reliefs.

>>I just checked this with the color tissue I am currently balancing.
>>There is not the slightest bit of dichromate left in the relief after
>>going through the entire process. Of course, with the traditional
>>process there are quite a number of steps when the tissue/relief
>>is in water. First, it is soaked for about a minute before being
>>squeegeed onto the plastic temporary support, then it is washed in
>>warm water for 6-8 minutes, then in cold water for another few
>>minutes to allow the gelatin to set.

>I still can't get over the fact they have a dichromate leftover problem.
>The one minute cold soaking is too short to help, but the hot water
>development of what? 6-8 minutes?,

10 minutes and a short while in cold water

>followed by the possibility of using
>several changes of cold water should clear everything if indeed it is on a
>plastic base. This is really a strange mystery.

Yes it is, but as we wrote earlier we clear them for security reasons. We
will bring a yellowish STS to Boston, in case of......

>>However, the problem of registering on a soluble transfer
>>paper *changing size all the time* as you state is really
>>a bear. Does anyone know of a dimensionally stable material (paper
>>or otherwise) that could be used to make a soluble temporary support?
>>It would have be to able to breathe, otherwise the relief would never
>>dry.
>
>Since I own the copyright, and my _History and Practice of Carbon
>Processes_ (1982) is out of print, I am granting myself permission to quote