> Has anyone heard of the catatype process?
Judy,
it was patented by NPG (Neuen Photograpische Gesellschaft, Berlin-Germany
-- a photographic factory) in 1903. (Phenomenon was invented in 1901 by
Ostwald and Gros.) One of the pre-methods of the Carbro process (like Ozobrom
or Ozotype, etc.). A contact-hardening process in the case of colloids.
However it is not only one process but a family of similar(?) processes. The
name of this process (Katatypie) was created from the word: catalyst
(Katalysator).
Briefly: the process use a silver-bromide DOP material for exposition (camera,
enlarger) but the final product is a pigment, gum, or even a manganese
picture(!), etc. The developed silver picture emulsion --in contact with the
"emulsion" of the final material (eg. pigment)-- will treated in a bath and
the chemical results of the process is hardening/reduce/toning the final
material where the density is existing (or where not existing) on the silver
DOP. I mean the process details are differents up to the final material.
> "decomposition of hydrogen peroxide into water and free oxygen ...
> by presence of finely divided silver, or better platinum."
Platinum: the silver DOP --negative-- is need platinum toning for better
performance...
The NPG made a lot of materials for this process: special paper negative,
pigment tissue, manganese paper, chemical patrons and so on... As I know
this process was not widely used in the practice. I successfully increased
now the fog about this process ;-). I have a few (more) sources so:
continue -- if necessary.
Balint
- Balint Flesch - Archaist/conservation photographer. - Budapest/Hungary. -