Jim and others on this list are more qualified than I am regarding the
practical side of collotypes. I have been studying a lot of them however,
going back to the inventor's work (Poitevin) in his own lab in Paris and I
have many specimens in my collection, including an original Albertype as
reproduced in my Encyclopedia.
>Do collotypes show a visible grain like allways happens with oil printing
>or is it nearly grainless like fine gravures ?
There are collotypes and there are collotypes... The quality runs the whole
gamut, like anything else. Luckily, collotypes are easy to find. Millions
of postcards were made by this process. Look for words like Lichdruck,
Phototypie, Phototype, Albertype and the many other synonyms on the back of
those cards. With a good magnifying glass you will be able to recognize
most (but not all) collotypes as you recognize the fine brain-like pattern
that is a common characteristic of their surface.
>
>What about the graduation? Do you get deep blacks and good high light
>details?
For monochrome deep blacks usually require two coats with contemporary
materials.
>I read that there are two versions: the >amateur version< and the
>>professional< one were drying conditions of sensitized emulsion are very
>important to produce the typical surface structure of the plate,
>important for successfull printing.
There are hundreds of variations.
>And it is saied that inking is easier than with oil printing and more
>>mechanical<. Is it true?
Maybe. It depends. An oil/bromoil master like David Lewis does not like
using a brayer (roller)
>More and more question...would be nice to hear anything about your technique
It may be expecting much to get a thorough course on such a complicated
process through a mailing list. Remember that months in the lab will save
you hours at the library;-) There are hundreds of references in my
Encyclopedia and I suggest that you try to get your hands on the most
recent books that make use of contemporary materials. The current issue of
the german _Rundbrief_ came with a collotype print attached to it and the
supplier's address is inside. The quality is not comparable to the
duotone/tritones Jim Frank has been making but it should be a start and
perhaps the print was not the very best the collotyper could produce.
In my opinion, oil, bromoil, collotype, photogravure, and color
carbon/carbro are more likely to require professional help than most other
processes.
Luis Nadeau