How was Tech Pan emulsion different?

[Ryuji]

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]

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]

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]

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]

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]

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]

>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]

Thanks Bill, When I cycle over to the tech pan I may give it a try.

 

[billtroop]

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]

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]

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]

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...&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]

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]

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]

Koslowsky

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.

 

[AgX]

It would be interesting to hear more about the successor emulsion [to Technical Pan], which I am anxious to test one of these days.

Successor? Did I miss something?

 

[Photo Engineer]

To Max;

I am trying to get a reference. The patent was pre 1975 and therefore is difficult to search for on the patent site. I know the inventor, but not the patent #. IIRC, I had the internal Technical Reports but turned them in when I retired. Sorry.

AgX;

In the 40s Kodak certainly had high speed films. So did Agfa. At the end of the war, Kodak applied gold to their high speed films, effectively doubling speed so that 50 speed films became 100 speed. Therefore, at the end of the war, Agfa was overall a bit slower or grainier than Kodak.

The Kodak technology was unique to Kodak and Agfa's was gold salts. As a result, Kodak gained the additive effects of their own and Agfa technology effectively giving them a lead. I might add that Ilford and others probably benefited as well.

Kodak now is using 2 electron technology which is akin to the advance of gold in the 40s. There are so many more, I just cannot describe them here, but one that comes to mind is the Kodak supersensitization which is the addition of an organic chemical which doubles or quadruples speed. This was known in the 40s. Unfortunately, these esoteric chemicals are only really known in internal documents.

I think it fair to say that anyone who claims otherwise, that they know the details of this and is not from Kodak, is either incorrect or has highly confidential information. Small pieces of this, of course, have been published.

PE

 

[rmazzullo]

Hello all,

I have to admit, this is somewhat perplexing. I was under the impression from my recent research that rudimentary feedback control was a recent (very late 70's, early 80's) innovation at Kodak, with full control not coming until much later. There seems to be conflicting information being presented here. If Tech Pan was made earlier than the late 70's, was Tech Pan made with or without control?

Thanks,

Bob M.

 

[Ryuji]

Bob,

The conventional double jet technique with feedback control to maintain pAg was published by AGFA people in 1964. I'm going to steer clear of Kodak-relate info for now due to some agreement with a few people, but this type of emulsion making setup (commonly called controlled double jet) was in use in research labs of Fujifilm already in 1960s. As I said before, it took a decade or two before this new technology saw practical use with advantage in commercial plant scale. (That is, even with the fancier machine, the engineers couldn't make better emulsion for some time, compared to the old-fashioned method.)

 

[Ryuji]

Dear AgX,

Did you know that I have a domain name AgX though it's not in very active use right now?

Anyway, I have a lot of things to say about your Koslowski post and response thereto, but I will limit my focus due to some agreement that is in effect.

The stabilizer I mentioned before, which you also mentioned, is 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene, commonly called TAI among emulsion engineers. (Note: this compound was called 5-methyl-7-hydroxy-triazaindolizine at that time, but these names refer to the same compound.) There are several derivatives of this compounds. This compound was the work of Birr at Wolfen in late 20s or around 1930. Fast AgBr or AgBrI emulsions that received optimal amount of chemical sensitization develop fog very easily during storage, so stabilizer is needed, but many antifoggants known then (e.g., 1-phenyl-5-mercaptotetrazole, commonly called PMT, and many other nitrogenous heterocycles with thiol group attached to the heterocyclic ring) severely decreased the photographic speed of such emulsions. So Birr was working on a LOT of organic compounds that have good stabilizing actions on emulsions but with minimal of speed penalty. He was a master of heterocyclic compounds at that time, and he found TAI and he also continued his entire career in photography in research of mechanism of how these compounds stabilize emulsions.

In the latest emulsion making processes, the role of "stabilizers" is not limited to post-digestion stabilization but they are more proactively used to control the crystal growth, specific location of sensitization within each grain, etc.

 

[AgX]

Dear Ryuji,

No, I did no general search for `AgX´. Only at Apug. (Here is another AgX around; he saw some light though…)

Thanks for naming this stabilizer. I only knew its structure, its `family´ name and its Agfa internal name. I did not dare trying to name the structure.
To my information it was in the late twenties that by two other Agfa people (Mathies/Wendt) the predecessor of that stabilizer was found, a sulphur containing heterocycle. Birr came to Agfa only in ’34 and found TAI in 1937 (after the presentation of the New Agfacolor film).
But I admit finding these dates is difficult and the results are not necessarily trustworthy as long one did not see the original documents, which I did not.
All this is getting very special and I guess annoying to some people and I sometimes think it would be better to have a special historic forum, but I do not see the smooth transition from issues coming up in other forums to that historic one.

 

[rmazzullo]

Bob,

The conventional double jet technique with feedback control to maintain pAg was published by AGFA people in 1964. I'm going to steer clear of Kodak-relate info for now due to some agreement with a few people, but this type of emulsion making setup (commonly called controlled double jet) was in use in research labs of Fujifilm already in 1960s. As I said before, it took a decade or two before this new technology saw practical use with advantage in commercial plant scale. (That is, even with the fancier machine, the engineers couldn't make better emulsion for some time, compared to the old-fashioned method.)

Thanks...

As a follow up, I'd like to do some further reading about this offline. Can you please give me the names / dates / numbers of the papers or patents where this is described by AGFA or Fujifilm?

Bob M.

 

[Ryuji]

No, I did no general search for `AgX´. Only at Apug. (Here is another AgX around; he saw some light though…)

Yeah AgX is a good name, but since it's so short it's hard to find a domain and can be expensive

To my information it was in the late twenties that by two other Agfa people (Mathies/Wendt) the predecessor of that stabilizer was found, a sulphur containing heterocycle.[...]But I admit finding these dates is difficult and the results are not necessarily trustworthy as long one did not see the original documents, which I did not.

1-phenyl-5-mercaptotetrazole is a famous sulfur containing heterocycle but I don't think it was from Wolfen. Another family of famous thiol, 2-mercaptobenzimidazole (2-MBI) and 2-MBI with substitution on the benzene ring are very commonly used, both in emulsion and developers, and this is from Wolfen. I thought TAI was late 20s but I was writing from memory, but it was actually the date of the previous generation compounds. I just searched for the date of TAI but date varies from 1935 or 1937. Birr has published a whole book but doesn't say the date of this work! Since this is not the only one he worked on but it just happened to be the famous compound, it may be hard to give a single date. Anyhow, it's mid 30s.

Glafkides say:

The most remarkable of all the photographic emulsion stabilizers are the
aza-indolizines discovered in 1935 by Birr.(32) They were kept secret for many
years, and enable gold sensitizers to be used which, as we know, produce
considerable storage fog.​

Duffin (the author of an old emulsion technology book) says 1935.

The website of Organica (ORWO) says:

1936 The "Agfacolor-Neu" is presented to the
world. It is the first multi-layered colour film with
inserted couplers and it wins the Grand Prize of the
Paris World Exposition.
The Sodium salt of the Benzenesulfinic acid
(00540, S-Salt) is used in the manufacture of
emulsions as an antifogging agent since the middle
of the 30 ́s. Later on, other film manufacturers
will use the corresponding salt of the
4-Toluenesulfinic acid (12060).
Trough his search for stabilisers, which do not
have any negative influence on the sensitivity
while using Mercapto compounds, Birr comes
across Triazaindolizines, which Bülow had already
synthesised in 1907. The condensation product of
Ethylacetoacetate and 3-Amino-1,2,4-triazole will
soon be considered to be the perfect stabiliser (12210, TM-2, Sta-Salt). Within
two years it is used in all types of film and replaces the Mebi acid in the
"Agfacolor-Neu" material. Thus, it permits the full benefit of the Koslowsky
effect. This unique combination of Gold complex and Sta-Salt, which has been
kept secret until the BIOS- and FIAT- reports were published, has been applied
world-wide since 1945 in all Silver halide materials.
Until 1945, China-, Oxa-, Selena- and Thiacarbocyanines in form of their
Iodides, Bromides, Chlorates and Ethylsulfates are used as spectral
sensitisers in all black-and-white and colour materials (12680).​

All this is getting very special and I guess annoying to some people and I sometimes think it would be better to have a special historic forum, but I do not see the smooth transition from issues coming up in other forums to that historic one.

I always think that forum is a better place for issues of current nature, that is, things that aren't fixed. Historical matters, among other things, are probably better served in the form of wiki or other forms where information is consolidated. Historical matters, of course, are more academic and meticulous checking with references and cross checking with multiple sources becomes more important, but doing this for every single thing in forums is tedious. I can make an AgX wiki site, or just join wikipedia, there are a couple of good options here.

 

[Ryuji]

As a follow up, I'd like to do some further reading about this offline. Can you please give me the names / dates / numbers of the papers or patents where this is described by AGFA or Fujifilm?

The Fujifilm info is from a short memoir (published) of an emulsion scientist who is now a professor. It is written in Japanese. I don't want to trouble him since he is still active in publishing his work at Fujifilm and he has also been very kind and helpful. If you read Japanese, let me know off list.

The AGFA report was by F. Claes and R. Berendsen (1965), published in Photogr. Korresp., 101, 37. Claes published a lot around that time, many in English or American journals. He worked at Mortsel lab with Libeer, Borginon, Vanassche, et al., and you can search their relevant work. Basically, controlled double jet method allowed to make a bunch of different kinds of crystals but appearing rather in isolation, due to a specific condition of crystal nucleation and growth. The technique also helped to make crystal size very uniform, called monodisperse emulsion. So monodisperse emulsion of a single crystal shape is a very good research model to investigate the photographic sensitivity. Also, various sensitization techniques were re-investigated on each crystal type in detail at that time. Many of their publications are around these issues. If you just want to get a detailed review of this topic, a very thorough review was written as a book chapter by Jong Wey of Kodak Rochester lab in 1981. The book title is Preparation and Properties of Solid State Materials, VOLUME 6, edited by Wilcox. It describes several theoretical models that were later used in model-based automatic control of plant equipment. He left many issues open-ended because the real answers weren't known then, but many new work, notably works related to tabular grain technology, built on the state of knowledge Wey summarized.

Since you are interested in automatic control, I mention Konica. One of the internal bulletin (public knowledge) described their emulsion process control using both feedback and model-based feed-forward control. The bulletin is written in Japanese, and the report was published in 1990 by Saitoh and Shimoji of Production Engineering Center of Photographic Products Manufacturing Division in Hino, Tokyo.

 

[AgX]

context

Ryuji,

I got my informations on this very topic mainly from publications by former Agfa/ORWO researchers and even they can be a bit contradictory concerning dates. For that non-speed-retarding stabilizer a patent (secret patent) has been applied for at 3 july 1937. (I’m quoting the date.)

But, to my mind, it is less important just to know a very date, but rather in which context a certain development is to be put.
How did people achieve certain ideas? Why was decided in favour of a certain research project? What was the market’s, the competitors’ response? How was the life of those involved touched? And, not at least, I think an invention can even have an inner beauty.