I Googled and forwarded Sullivan's request to an e-mail to all of Klaus
Pollmeier's addresses I could find.
He said the reply to the list.
----- Forwarded message from KNMDI -----
>From info.knmdi@abk-stuttgart.de Tue Aug 18 13:52:58 2009
From: "KNMDI" <info.knmdi@abk-stuttgart.de>
To: "'Richard Sullivan'" <richsul@earthlink.net>
Cc: <beepy@netapp.com>, <mineurdecharbon@skynet.be>
Subject: carbon and gravure tissue
Dick,
good to hear from you again! It's quite a while that I was last involved in
carbon printing but I still do demonstrations for my (conservation) students
once a year. Still keep some rolls of Hanfstaengl-tissue in my basement, 17
years old now an
d almost fog-free...
To answer your questions: I was helping Hanf
staengl to improve their
products and selling their carbon tissue until 1992, when they finally went
out of business. At the end they were supporting the company with revenues
from their real estate in Munich, which the family did not really like too
much... Anyway, I immediately asked them for their small lab coating machine
(kiss-coating...), which allowed to coat one sheet of approx. 1 foot x 3
feet at a time. They regretted and said that they cannot sell or give away
their lab equipment yet, because it was bought by the German gelatin
manufacturer Stoess, who wanted to produce thin gelatin foils on
Hanfstaengl's (giant) kiss coating machine and they would need their lab
machine, too.
As it turned out, Stoess soon lost interest in this business, although the
Hanfstaengl machine was almost brand new, but too slow for mass production.
When I heard about that, I asked Stoess again for the small lab coating
machine, but had to learn th
at everything, including the big machine, was
sold as scrap metal a few weeks earlier...
When Hanfstaengl and I last talked about making carbon tissue, their last
statement was that they do not want to see their original formulas
published. On the other hand I can say that their formulas didn't contain
anything unsusual and that they were made of readily available, industrial
products, however under very controlled working conditions. To use their
formulas, one would also have to know the coating speed and coating
temperature, which determins coating thickness (dry approx. 50 nm) - figures
I do not know. The amount of pigment will depend on the brand of the
dispersion. And they prepared the dispersion with a stone mill that would
run overnight and would provide them with very finly grounded and perfectly
dispersed pigment mixtures. Gelatin is a chapter of its own... Maybe Stoess
will tell you what they delivered to Hanfstaengl. They are
known for good
record keeping. I don't remember the exact Bloom
strength, probably around
230 (???)
An emulsion similar to those made by Hanfstaengl could have been like the
following:
Total amount of water (dist.) 370.0 ml
Phenol (or another desinfectant, small amount)
Glycerin 18 ml
Gelatin (medium to high bloom strength) 60 g
Wetting agent (small amount, depends on product)
Lampblack (Dispersion) 8,4 g
Quinachridone violet R 3,6 g
As of the G25 paper - the excellent Hanfstaengl tissue for hand gravure - I
do not know any details. I also never sold it, because Hanfstaengl had
special dealers for it. I am quite sure though, that it more or less was
based on the above formula, with an iron oxide dispersion as colorant. You
then still have to find a formaldehyde-free base paper... (You can test the
base paper by heating it in contact with an unsensitized carbon tissue in a
sealed plastic or aluminum envelope, then develop the tissue and watch
for
fog...)
I hope this helps - I really cannot tell much more about it, since I just
don't know more production details...
BTW: I once quitted the alt-photo-list (or was it terminated? I don't
remember, just remember the problems with Terry the king...) Is there
another list worth watching right now? If you like, you are welcome to
publish the above mentiones historical or technical aspects on that list. Is
there any reasonable interest in carbon transfer printing today? With
reasonable I mean - good photographers producing interesting photographs on
a more than amateur level?
Please let me know, if you get into the production of gravure tissue - I get
requests from time to time and would refer to you then.
Best regards,
Klaus Pollmeier
____________________________________
Stuttgart State Academy of Art and Design
Conservation of New Media and Digital Information (M.A.)
Am Weissenhof 1
D-70191 Stu
ttgart
Germany
Phone: +49 (0)711 28440 322
Fax: +49 (0)711
28440 225
www.mediaconservation.org <http://www.mediaconservation.org/>
----- End of forwarded message from KNMDI -----