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Ryuji
04-27-2007, 09:31 PM
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 ..

Ryuji
04-27-2007, 09:46 PM
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 :

Photo Engineer
04-27-2007, 10:10 PM
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

Alex Hawley
04-27-2007, 10:26 PM
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'".

Photo Engineer
04-27-2007, 10:32 PM
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

Ryuji
04-27-2007, 10:40 PM
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.

Alex Hawley
04-27-2007, 11:32 PM
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. :)

rmazzullo
04-28-2007, 01:30 PM
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.

jd callow
04-30-2007, 12:40 PM
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?

Tom Hoskinson
04-30-2007, 01:18 PM
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).”

Ryuji
04-30-2007, 02:34 PM
Tom,

Well, the base crystal technology used in Tech Pan could be from late 1960s. Conventional double-jet method was described by AGFA people in 1950s and it was known since then. Automated and semi-automated feedback control system also existed. HOWEVER, these techniques were used to make research emulsions and possibly some special purpose emulsions (which Tech Pan could fall within) but not for practical commercial emulsions until 1970s. Like I said before, these techniques are easily done in a batch size of a couple of liters but not in the scale of production plant, and in order for the technology to transfer, the emulsion scientists had to acquire enough insight into this "scaling problem" and then ways to solve the problem, such as pre-mixer, the curvature of the inner surface of the tank, nozzle placements, and other techniques.

billtroop
04-30-2007, 05:46 PM
>What is TD3 and how might it enhance or work well with techpan?

TD-3 is a formula I put on the market several years ago through Photographers Formulary, primarily for Tech Pan but also for similar films. As packaged, it is optimized for TP, but anyone could easily use different dilutions to optimize for other high contrast films.

The pros and cons of using it are more fully documented in The Film Developing Cookbook in the chapter on document films. TD-3 gives far from straight-line development, but it does give the most pictorially pleasing results of any document film developer I have ever seen when used as directed, as well as the longest tonal scale. It has a pronounced tanning stain, intentionally, but Grant Haist theorized that a physical development reaction was occurring as well, at least with Tech Pan. T.H. James concurred, but for reasons that were quite beyond my ability to understand. TD3 is an interesting developer! Much more so than I realized when I was formulating it with considerable innocence. Granularity was lower and definition was higher than in the more conventional developers being assessed at that time, findings that surprised me.

But truly, the only reason to use it is aesthetic. Either you like what I describe as the 'marbly' appearance it provides, which is truly unlike that of any other developer out there, or you don't. It's not a 'clinical' developer, and it wasn't intended to be.

Let me take this opportunity to thank Geoffrey Crawley, still writing most interestingly for Amateur Photography in the UK, for providing me with the germ of the idea that led to TD-3, and to Grant and the late great Howard for helping me to understand it.

jd callow
04-30-2007, 06:01 PM
Thanks Bill, When I cycle over to the tech pan I may give it a try.

billtroop
04-30-2007, 06:04 PM
Just a last word. The question of this thread was, 'How was Tech Pan emulsion different?' and the answer, that it used a unique halide conversion technology, is of course proprietary, but I see no harm in revealing that much now that it has long ceased production. The point to keep in mind is that, although the technology was highly innovative and ingenious, most people thought the film was inferior to the conventionally manufactured emulsions it replaced. As far as I know, this particular technique was never used for any other materials, either by Kodak or by any other manufacturers. There are some related patents but they were carefully designed to mislead. One important practical difference between TP and the normal high contrast document emulsion is that TP requires normal fixing times, whereas many of the less sophisticated (and finer grained) predecessors would clear in sodium thiosulfate in a second or two. For all its failings, TP was much easier to handle than its predecessors, and although there were occasional production glitches, Kodak did a phenomenal manufacturing job with it, given the mix complexities. It would be interesting to hear more about the successor emulsion, which I am anxious to test one of these days.

Photo Engineer
04-30-2007, 06:27 PM
Since I never worked with Tech Pan emulsion (knowingly) I cannot comment. Plant and research #s were totally isolated for security.

I do know that converted emulsions and core shell emulsions share a great deal of commonality. Pure so-called core shell emulsions are in current use at Kodak. Converted emulsions were also used for direct reversal. They were used in several negative and positive products I did know about including PR-10 instant film, Ektaflex R paper, Ektacolor 70 series paper, and the never released Directachrome R paper.

Core shell emulsions are in current use in a number of products.

These were/are double run emulsions, in which the early versions had no automation or control whatsoever. I'm not sure of the last ones made for PR-10 though.

PE

rmazzullo
04-30-2007, 07:27 PM
Thank you Bill and PE,

I have been following your posts with great interest, and this information fills in quite a few blanks. If you have more to share, I am all ears (eyes?)

Bob M.

maxbloom
04-30-2007, 08:47 PM
When I searched the US patent site for Kodak btw 1950 and 1970, I only got a couple results. Am I searching too early? Or would the evasive TP patent be listed under something other than Kodak?

In other news, I did come across this:
http://patimg2.uspto.gov/.piw?Docid=03312675&homeurl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fn ph-Parser%3FSect1%3DPTO2%2526Sect2%3DHITOFF%2526u%3D% 25252Fnetahtml%25252FPTO%25252Fsearch-adv.htm%2526r%3D2%2526p%3D1%2526f%3DG%2526l%3D50%2 526d%3DPALL%2526S1%3D(%252540PD%25253E%25253D19600 101%25253C%25253D19700101%252BAND%252BKodak)%2526O S%3DISD%2F1%2F1%2F1960-%3C1%2F1%2F1970%252Band%252BKodak%2526RS%3D(ISD%2F 19600101-%3C19700101%252BAND%252BKodak)&PageNum=&Rtype=&SectionNum=&idkey=NONE&Input=View+first+page

It's some chloride emulsion. The chemistry I understand, but beyond that, does anyone have a clue what it is?

Photo Engineer
04-30-2007, 08:56 PM
This concerns synthetic organic chemistry and has nothing to do with emulsions as far as I can see from a cursory examination. I've bookmarked it to come back later to go over it better.

PE

maxbloom
04-30-2007, 09:08 PM
Ah, I see now. I was misunderstanding the use of the word film in "exceptional properties which can be made into films." And that's not even sarcasm!

So, PE, might you be able to shed any light on the best route to tracking down the TP patent?

AgX
04-30-2007, 09:17 PM
As Ryuji started on Koslowsky and his gold-effect:


Dr. Koslowsky and his co-workers started on the findings of other scientists who published before that the use of colloidal gold increased the speed.
Koslowsky started with gold chloride added at the riping stage.
He looked at the efficiency of gold salts used for toning! and realized that 1-valency gold was superior and the efficiency could even be increased by accompanying it by rhodium salts. From this he developed the Agfa goldsensitation with Ammoniumaurorhodane (3-valency gold), where the Ag-nucleus of the latent image will be exchanged by an Au-nucleus (Koslowky's theory).

About that Kodak Super XX issue:
In ’39, thus three years after the secret introduction of goldsensitation at Agfa, Agfa found gold in the Super XX. Kodak is said to have patented their own gold-effect in ’41.

PE repeatedly stated that the Koslowsky-Effect was the one and only Agfa secret unknown to Kodak. That there are contrary statements is probably also due to reports from Agfa/Orwo themselves who speak of two further secret agents. (One being an stabilising agent.) But as it is hard to state that someone else does not know one ones secrets, I rather believe PE’s statement.
Dr. Walther (from Agfa-Wolfen research) 1997: “This in the production of silverhalogenic material up to now unique combination of goldcomplexes/stabilizing salt has since 1945 been used in all film materials of the world.” But again, this does not necessarily mean that Kodak did not know this salt and its use before.


Koslowsky himself stayed at Wolfen during the weeks of US-occupation and did not left for Leverkusen as others did in that period. (About 60 leading personnel are said to have left/fled until about ’48.) Due to being a local functionary of the NSDAP he was interned by the Soviets for three years after the retraction of the occupational zone. (Strange enough he was not sent to the Ukrainian Shostka film plant instead.) He came back to Wolfen and regained a leading position but fled after 2 years to the West as he felt intimidated by the new socialist party of the GDR. In spite of going overseas he went to Leverkusen where he stayed until to be pensioned.