Sandy King (sanking@hubcap.clemson.edu)
Tue, 02 Nov 1999 08:36:09 -0400
Hi Hans and Chia,
I too have been away from e-mail for a while and am just now getting around
to answering some old correspondence.
>In the meantime we have looked in some old books and papers, like "Colour
>Photography in Practice" from 1948 by D. A. Spencer (the Vivex-Spencer) and
>"the Keepers of Light". A question that pops up is if these old formulas
>still are useful. Or do anyone of you have formulas that are more suitable
>for todays paper and chemistry?
Most of the old formulas are as useful today as in the past. One of my
favourties of the old ones is the Devin ABC formula. It is a one-shot
sensitizer that you mix from stocks A, B, and C, then discard after use.
Have anyone of you read the Carbro chapter
>in Richard Farbers book, Historic Photographic Processes, 1998? If, what is
>your opinion about his single-bath-sensitizing?
This formula works well, but being a re-usuable one, has a limited
capacity, and exhausts progressively so that each print through the bath
will bleach slightly differenlty (increasing contrast). Even so I have made
many nice prints with it.
>We will start with non transfer on barytapaper. Sandy mentiones Luminos SW
>Art, isn't that the same paper as Kentmere Documenta Art used by the
>Bromoilists? Talked with an old friend in UK, Maija McDougal (bromoiling at
>APIS 99), and she said that this paper is not available anymore. She has
>changed to a RC paper (Forte) that works very good for her purpose. We
>would, however, try a thin barytapaper, so, if not finding any
>non-supercoated paper, do you have any hints and directions?
You can also do the non-transfer on RC papers, though for aesthetic reasons
this may not please you. However, Kodak Polycontrast RC, N surface, has a
very interesting surface appearance in carbro. I use if for all my initial
tests. Also, for purposes of contrast control a multi-grade paper is highly
useful.
>Sandy, you also say that a mechanical roller squeeging apparatus is
>necessary. What do you think of an old Agfa Proof developer?
>Are there any differences in making the carbon tissue compared to the
>tissue you make for the carbon, i e concentration of "something" or
>emulsion thickness?
Yes, I believe a roller squeege is absolutely essential for consistent high
quality work. I made my own from an old Anchor photo wringer, with double
rollers about 27" wide, that allowing tensioning. You can get a good idea
of design from many of the old carbro books, including the Spencer edition
you mentioned.
I have used the same carbon tissue formulas for carbon and carbro. However,
especially in color, it is much easier to balance a tissue set for carbro
than for carbon because you don't have to worry about the different
contrasts produced by yellow, magenta and cyan tissues.
>Sorry for bothering you with all these thoughts and questions but in this
>part of the world (Scandinavian countries) it isn't that common with
>alt-photo. There are just a few of us who work with it more seriously.
>Mostly it is Pt/Pd, gum and photogravure. We are probably the only ones
>making classical carbon especially the tri color one. But we have never
>tried carbro.
Carbro is a very tricky pocess and the chemistry is precariously balanced.
Since you have already gotten good results with tri-color carbon you may be
very frustrated with carbro. Even so, in my own work I have found it easier
to make good color prints with carbro than carbon, though for monochrome
work I find carbon highly preferable.
Sandy King
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