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  1. #21

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    Incidentally, if you are interested in the development of photographic emulsion technology after the rest of the world learned about the achievement of AGFA Wolfen, there is a nice article written by Hellmut Mueller, then at Ansco Research Lab in Binghamton. Mueller was a collaborator of Koslowski at Wolfen when they worked on gold sensitization and he later moved to the U.S.

    PHOTOGRAPHIC SCIENCE AND ENGINEERING
    Volumo 6, Number 3, May-June 1962

    Progress in Emulsion Techniques Since 1945*
    F. W. H. MUELLER, Ansco Research Laboratories, Binghamton, N. Y.

    The first paragraph goes (This is OCR so please pardon the inaccuracy):

    Emulsion techniques and formulations, as they are
    practiced presently in the photographic industry are
    tightly interwoven with other problems such as
    gelatin selection and have to be designed to meet
    development specifications. Thus, a review of the
    subject cannot be completely segregated from such
    related fields. The author will try to avoid overlaps
    with subjects recently reviewed, such as that covered
    in the excellent review prepared by Wood1t on "The
    Role of Gelatin in Photographic Emulsions."
    Nevertheless, a discussion of emulsion techniques
    will require occasional reference to some of the more
    recent theoretical concepts of chemical sensitization
    and latent-image formation ..

  2. #22

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    Here's another bit of info about Koslowski's work. This is OCR from German text so it's kinda ugly. If there's a German participant who promises to translate it for us, I'd be glad to send a bit more in better shape, which describes the birth of Isochrom and Isopan.

    There's also a paper authored by Koslowski himself. I have that somewhere in my file but haven't digitized them yet.


    Ein ganz erheblicherI damals geradezu sensationell wirkender Fortschritt gelang 1936
    der AGFA. Das von Dr. KOSLOWSKY und seinen Mitarbeitern erfundene Verfahren wurde
    zunächs geheim gehalten, erst nach dem zweiten Weltkrieg wurde es durch Veröffent
    lichungen amerikanischer und englischer Stellen bekannt. Das Verfahren verdient wegen
    seiner außerordentliche BedeutungJ die z. B. von der Wiener photographschen Gesell-
    schaft 1953 durch die Verleihung der Goldenen Medaille der Gesellschaft an Dr. KOS-
    LOWSKY anerkannt wurde [174: 89. 1953. S. 1391~ und als einer der bedeutendsten Fort-
    schritte in der Herstellung fotografischer Emulsionen bezeichnet wurdeI mehr als eine nur
    kurze Erwähnun verdient L222 : 46. 1951. S. 651 :

  3. #23
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    I have read all of the reports from WWII. The only new item was gold sensitization. Everthing else was well known by Kodak and Agfa used some Kodak technology as well.

    The Agfa technical people were deliberately obscure in their revelations leaving out temperatures and addition times and rates here and there to make it impossible to replicate the formulas. There was nothing new there, as I said, except gold sensitization. No new organic chemicals were revealed to the world. And the interviewers didn't know any better!

    One of the favorite phrases in those reports by the German scientists was "Es is hier unbekannt" (It is unknown here) reproduced in my probably fractured German from memory. In other words, solutions were moved between plants without identification, to keep formulas confidential. The same would be true if you tried to read a Kodak formula. You would need a roomful of Kodak engineers to decipher a fomula and there were few of us trusted with the whole thing.

    There were emulsion formulas, addenda formulas, finishing formulas, spectral sensitization formulas and coating formulas to name a few. This obfuscates a given product to the extent that no one outside of Kodak knows anything except the few who did it.

    You know, this is getting both amusing and tiring at the same time. In any event, the material above is from the 40s. Rhodium for example, was superceded by Iridium and some organics. So technology is far beyond what is known and published. Much of it remains totally arcane and beyond the knowledge of those not there.

    PE

  4. #24
    Alex Hawley's Avatar
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    Quote Originally Posted by Ryuji View Post
    Emulsion techniques and formulations, as they are
    practiced presently in the photographic industry are
    tightly interwoven with other problems such as
    gelatin selection and have to be designed to meet
    development specifications. Thus, a review of the
    subject cannot be completely segregated from such
    related fields. The author will try to avoid overlaps
    with subjects recently reviewed, such as that covered
    in the excellent review prepared by Wood1t on "The
    Role of Gelatin in Photographic Emulsions."
    Nevertheless, a discussion of emulsion techniques
    will require occasional reference to some of the more
    recent theoretical concepts of chemical sensitization
    and latent-image formation ..
    That's a heck of a way for saying "we ain't tellin' nuthin'".
    Semper Fi & God Bless America
    My Photography Blog

  5. #25
    Photo Engineer's Avatar
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    Alex;

    The poster don't know nuthin either about the inner workings nor does he have a complete set of the reports from Agfa. I have read them all except for 1. That one, AFAIK is still classified.

    PE

  6. #26

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    Quote Originally Posted by Alex Hawley View Post
    That's a heck of a way for saying "we ain't tellin' nuthin'".
    That's the only first paragraph of an entire report (6 pages) that contains many bits of information but because this work is subject to US copyright I am not going to copy and paste the whole report. You can go to your library and ask for the entire report. All the citation info that the librarian needs to locate the report is in there.

    Mueller is actually one of the very generous authors who writes very informatively. He is an expert in sensitization and radiation sensitive systems (X-ray, nuclear track and other non-light based emulsions) and the reports he wrote on these topics are very good.

  7. #27
    Alex Hawley's Avatar
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    Thanks for the tip Ryuji, but I'll probably have to pass on that one. Highly doubt that my local library would have it. Maybe I should ask just to see if they can get it sent in.
    Semper Fi & God Bless America
    My Photography Blog

  8. #28
    rmazzullo's Avatar
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    Thanks everyone for the detailed responses regarding Tech Pan....

    I am building a library of research material as I go, and appreciate the background information contributed on this topic.

    Bob M.

  9. #29
    jd callow's Avatar
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    Maybe a bit off topic but, I have 50 sheets of techpan in 4x5. I had planned on souping it in C41 dev, but I'd be interestedin experimenting. What is TD3 and how might it enhance or work well with techpan?

    *

  10. #30

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    We used a lot of Tech Pan during the 1970's and 1980's for both photomicrography and astronomical photography. We developed it in D-19, POTA and in Technidol depending on the application.

    Here is a quote from Sky and Telescope, September 20, 2004:

    “Kodak introduced Technical Pan Film SO-115 film in 1977 as a green-sensitive modification of its Solar Flare Patrol Film SO-392 available since the late 1960s (and also marketed as Photomicrography Monochrome Film SO-410 during the '70s).”
    Tom Hoskinson
    ______________________________

    Everything is analog - even digital :D

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