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rmazzullo
04-02-2007, 11:32 AM
Hello everyone,

I wanted to know if anyone knows how (without venturing too far over the "proprietary information" line) Kodak's Tech Pan emulsion construction / formulation / etc., differs from other B&W films, and if there is any patent discussing the Tech Pan emulsion.

Also, being new to the forums, I see references to books mentioned on this forum by the author(s) last name(s), but no titles. I would guess this is because these books are well known to the list members. Is there a post on this forum or some other source which gives details of the book titles and their respective authors?

Thank you,

Bob Mazzullo

David A. Goldfarb
04-02-2007, 12:01 PM
Hmmm...a traditional photo bibliography with complete citations on APUG--that wouldn't be a bad idea, but meanwhile there's the search engine, and that might help you track things down. And if you don't find what you're looking for, you might just ask in the thread that mentions the source that you're interested in.

Photo Engineer
04-02-2007, 12:09 PM
Here are two very good textbooks:

Mees and James "The Theory of the Photographic Process"

Haist "Modern Photographic Processing"

Tech Pan was a very fine grained sharp rather slow film. That is about all I know about it. I never did any work with it at all.

PE

rmazzullo
04-02-2007, 02:13 PM
Thanks David, and PE for the information,

Bob Mazzullo

Peter Black
04-02-2007, 03:12 PM
There's some information on the Kodak website if you haven't already seen it.

http://www.kodak.com/global/en/professional/support/techPubs/p255/p255.jhtml

Maine-iac
04-27-2007, 07:13 AM
Hello everyone,

I wanted to know if anyone knows how (without venturing too far over the "proprietary information" line) Kodak's Tech Pan emulsion construction / formulation / etc., differs from other B&W films, and if there is any patent discussing the Tech Pan emulsion.

Also, being new to the forums, I see references to books mentioned on this forum by the author(s) last name(s), but no titles. I would guess this is because these books are well known to the list members. Is there a post on this forum or some other source which gives details of the book titles and their respective authors?

Thank you,

Bob Mazzullo

I'm out of my depth in this forum; my high school chemistry class was light-years ago. So I can't give you the technical details about Tech Pan. I did, however, have a several-year-long fascination with it back in the 80's. I believe it was originally designed for high contrast lithographic work. With many conventional developers, it gave very, very high contrast results--almost just pure blacks and whites.

However, in a POTA-style low-contrast developer, it gave a normal range of tones. It had a variable film speed, depending on the developer being used, and was super-fine grain, much finer than Panatomic-X or T-Max 100. Mostly I shot it at around ISO 25.

What was interesting about it was that it had a built-in red sensitivity (orthochromatic), so that it gave results similar to using a light orange filter over the lens with a normal panchromatic film. This intrigued me, because I normally shoot B & W with a yellow filter over the lens at all times anyway. (T-Max films have something of this red-sensitive quality also), and it was nice to not mess with filters, but get the darker sky effects anyway.

I began using it because, at the time, I couldn't afford a medium format or large format outfit, and I was stuck with my 35mm and wanted to get my photos to look as sharp and grainless as those done on 4X5. Tech Pan did that admirably, once I got the hang of correctly developing it. I did 11X14 blowups that look as though they were done with 4X5--absolutely smooth tones and no visible grain. Eventually, I found the slow speed limiting and was able to acquire a medium format outfit, and well, I just never went back. But it was definitely an interesting film.

Larry

jnanian
04-27-2007, 07:37 AM
hi bob

i loved using tech pan at high speeds ( like asa 100 and 200 ) and processing the film in print developer to give a higher contrast and no grain negative.
unlike lith film, there were always mid-tones ... great stuff!

john

Ryuji
04-27-2007, 08:20 AM
Also, being new to the forums, I see references to books mentioned on this forum by the author(s) last name(s), but no titles. I would guess this is because these books are well known to the list members. Is there a post on this forum or some other source which gives details of the book titles and their respective authors?


If it's my post, I can supply those info. If you are seriously interested, feel free to write me but please include your email address.

Also, check this out:

http://wiki.silvergrain.org/wiki/index.php?title=Literature



I wanted to know if anyone knows how (without venturing too far over the "proprietary information" line) Kodak's Tech Pan emulsion construction / formulation / etc., differs from other B&W films, and if there is any patent discussing the Tech Pan emulsion.


I still have quite a bit of Tech Pan (they are for sale too!) so I could analyze the emulsion for some basic parameters...

The Tech Pan is most different from pictorial negative films in (1) extended red sensitivity, (2) inherently higher emulsion contrast and much narrower exposure latitude, (3) finer crystal size.

The extended red sensitivity is due to a different sensitizing dye. The higher emulsion contrast is due to more uniform crystal sizes in very narrow size distribution (many negative emulsions use multiple emulsions of different grain sizes to increase latitude and decrease contrast).

Tech Pan was introduced in late 1970s. Considering the emulsion making technology of that time, and the required specification for Tech Pan, I think the most likely choice would be cubic AgBrI crystals of edge size about 0.1 to 0.2 micron. Well, the right answer can be found easily by dissolving a bit of emulsion off the film and looking at the crystals under electron microscope.

This type of emulsion was most commonly made with a conventional double jet system. Most likely with a reaction vessel with a premixing chamber, a pair of electrodes to monitor pAg, pH, and temperature, with automatic feedback control system. The flow control of both jets (silver jet and halide jet) is very critical to maintain a certain target pAg value, or the emulsion won't be as high contrast. And the target pAg ideal for high contrast emulsions will most naturally make cubic AgBr crystals, unless the crystal habit is chemically modified, but at that time this technology wasn't developed yet.

In order to make a high resolution emulsion, you must design the crystal size very carefully. Emulsions with crystal sizes in 0.2 to 0.5 micron range is not very easy to use for very high resolution applications because of large scattering of light caused by the crystals themselves. Tabular grain emulsions have a definite advantage here.

Incidentally, many paper emulsions are in the size of 0.2 to 0.5 microns. They are also coated on reflective paper. So they have terrible resolution although the emulsion is very slow compared to the negative emulsions.

Also, Technical Pan is not a lith film, as users of both types of film can tell. Lith films are usually AgClBr emulsions, possibly with a very small amount of iodide. Bromide emulsions don't develop very well in classic lith developers that was in active use at the time of Tech Pan's introduction to the market.

Keith Tapscott.
04-27-2007, 11:54 AM
Hello everyone,

I wanted to know if anyone knows how (without venturing too far over the "proprietary information" line) Kodak's Tech Pan emulsion construction / formulation / etc., differs from other B&W films, and if there is any patent discussing the Tech Pan emulsion.

Also, being new to the forums, I see references to books mentioned on this forum by the author(s) last name(s), but no titles. I would guess this is because these books are well known to the list members. Is there a post on this forum or some other source which gives details of the book titles and their respective authors?

Thank you,

Bob MazzulloYou could contact Michael Maunder about this film, which he has used from it`s name as SO-115 through to 2415 Technical Pan for astronomy.
This he has developed in a wide variety of developers such as Kodak D-19, P.O.T.A, D-23, C-41 through to his own formulated processes such as Celer-Stellar and Celer-Reverser.

http://www.speedibrews.free-online.co.uk/

Emile de Leon
04-27-2007, 02:29 PM
Tech Pan is great stuff. I used to use it with a very high resolution Leica DR Summicron and the results were astounding. I got good results with Photographers formulary TD3 and sometimes good results with Kodak technodol. I wish it was still made, a great portrait film as well. Emile/www.deleon-ulf.com.

Sparky
04-27-2007, 02:29 PM
From what I understand- it was a (slight) modification of an earlier emulsion that Ryuji is referring to - it was called "solar patrol film", so-called because of it's acute sensitivity to the hydrogen-alpha absorption line in the color spectrum. This is particularly useful for astronomical photography. That's a fancy (and particular) way of talking about it's red-sensitivity. I presume the engineers at kodak noticed that it was particularly fine-grained as well, and so decided to try to bump up it's green sensitivity. From what I recall the earlier 'solar patrol' film wasn't very green sensitive. A lot of red and some blue... others may know more about it. But you can use the term "solar patrol film" to search with on google and come up with more.

Photo Engineer
04-27-2007, 03:16 PM
Someone directed my attention here to look at Ryuji's post. He is ignoring my posts or he would see that his pretty much repeats one of mine in another thread. There I give the specific pAg and vAg along with salt concentration values for giving cubes, octahedra and t-grains.

In addition, the method of maintaining control of grain size and uniformity by process control is the subject of exchanges between Bob, myself and several others. I direct you there for more information.

Basically, there are many ways to get high contrast and fine grain other than monodispersity. Offhand, I don't know how Tech Pan was made. I have no experience with it. However, I direct your attention to the Lith formula in Haist which has no feedback control but gives an exceptional high contrast emulsion. My own AgCl Azo type emulsion can be made with high contrast but with no control. So, the argument of control being needed for high contrast is not necessarily correct.

In addition, the sharpness of fine grain emulsions can be controlled by acutance or absorber dyes within the coating, so in this Ryuji is totally incorrect.

Take a look at color paper sometime. It is blue to increase sharpness when a fine grained emulsion is used. The paper itself is quite sharp thereby.

PE

jimgalli
04-27-2007, 03:56 PM
Everything I will say is pure seat of the pants and easily refuted scientifially I suppose. Tech Pan is extremely fussy and unfogiving stuff. That appeals to some of us who love the challenge and figure there's nothing photographic we can't conquer. Luckily I have a short attention span and get over the conquer thing fairly quickly.

Cake and eat it too....there is another film, equally tricky to get, but it possesses all the fine grain character of Tech Pan but is far more forgiving in use. It was / is Kodak Aerial Panatomic X. I rate it at ASA 32. I've filled my freezer with a lifetime supply early on. It keeps well and I've used some that was 25 years old that was still very low fog. It comes in 5" and 9 1/2" long rolls for the airplane cameras. I most use it in 5X7. Simply cut 7" pieces and load them. Under a microscope I've compared the PanX, Tech Pan, and Efke 25 side by side for grain structure. I felt the Aerial Pan X was the nicest of the 3. Granted, I bought it right on Ebay, but a typical 5X7 neg with this stuff costs me about 17 cents. Also rumored that this was the stuff Polaroid always used with their Neg Pos Type 55 product. I can't substantiate any of this nor would I bother. 7 minutes in Rodinal 1:100 is a good starting place.

I have most of a 150 foot 35mm long roll of Tech Pan for sale if anyone is interested. I'll guarantee there's 125 feet there and figure a buck a foot if you want it. Expired in 2002 iirc.

Photo Engineer
04-27-2007, 04:01 PM
Thre is no evidence that Polariod ever used a Kodak emulsion although Kodak did help get Polaroid film (Color and B&W) up and running for Land. As for the films in question, I should point out two things.

1. I was not equating the Lith effect with monodispersity. Just pointing out that you can get high contrast by other means with other emulsions.

2. Agreeing with you Jim, high contrast or good tone scale predates the ability to use control in making emulsions. Process control only became feasible with process control electronics. The manufacture of Pantomix X or any of the others predates the use of process control at Kodak.

That aerial film was superb.

PE

Ryuji
04-27-2007, 04:43 PM
Everything I will say is pure seat of the pants and easily refuted scientifially I suppose. Tech Pan is extremely fussy and unfogiving stuff. That appeals to some of us who love the challenge and figure there's nothing photographic we can't conquer. Luckily I have a short attention span and get over the conquer thing fairly quickly.

Cake and eat it too....there is another film, equally tricky to get, but it possesses all the fine grain character of Tech Pan but is far more forgiving in use. It was / is Kodak Aerial Panatomic X. I rate it at ASA 32.


I agree trying to use Tech Pan for continuous tone pictorial application is very tricky unless the subject brightness range is low. But Tech Pan is a special purpose film as the name says. Tech Pan was meant for a broad range of technical applications that are not covered by other films, and it is very unique in many regards. One feature is that it is compatible with a very wide range of developers to produce a wide range of contrasts, although the inherent contrast of the emulsion is very high due to tightly controlled (for late 70s anyway) monodisperse emulsion. Other high contrast emulsions, very common for printing films (line films) and duplicating films, are much slower for the same grain size, and they are much more difficult to vary their contrast without losing good sensitometric properties. Lith film is another variation. These high contrast films can reach much higher contrast, in a suitable developer, compared to Tech Pan, but taming their contrast is a much tougher job than with Tech Pan.

Panatomic-X predates Technical Pan by many decades and it was made with very different technology, at least for the old batches. One has to recognize though, the emulsion making technology saw a few big waves of improvements after the WW2, and emulsions often received improvements when the method of making changed. Also, emulsion makers saw improvements in sensitizing dyes.

To add one more point to the question posed in the title of this thread, many negative emulsions of that time contained a rather wide range of grain sizes and sometimes also different grain shapes. Many camera negative emulsions of that time look irregular shaped, like a bag of potatoes, in electron micrographs. Many of them are corrupted versions of octahedral habit. You see some cubes and tabular grains mixed in as well.

If you want to make your emulsion, Panatomic-X type emulsion requires the simplest setup, doesn't require a lot of sophisticated measurements and control, but still requires some skills to do it right. You can incorporate the latest knowledge and technology to enhance the speed with the same grain size, or even make it tabular grain and use the latest sensitizing dyes that give you extended red sensitivity. (But then you'll have to coat and dry it in total darkness.) Tech Pan type emulsion requires more involved setup and close regulation of the making process.

Emulsion making is very different from mixing processing chemicals. Even if you copy my emulsion formula and try to make it yourself, it is highly likely that you'll get different results. Changing the reacting vessel or method of agitation can change the way crystals grow and it will affect the emulsion. Another big difference is where you buy your gelatin from, and there is variation across and within each batch number of the raw gelatin. Emulsion science has seen much progress in this area but most emulsion makers buy gelatin in bulk and test them very closely before using them. So in this sense, who took who's emulsion kind of rumor has little substance. We've also heard that BPF200 is/maybe/was a copy of Super-XX Pan, or some 25-speed or 32-speed was/maybe/could be a copy of such and such legendary emulsion of the same box speed, but you can safely judge such rumors are irrelevant and most likely incorrect unless the new producer bought the same plant and hired the same people to make it.

Photo Engineer
04-27-2007, 05:33 PM
I am a bit at a loss at this last post here by Ryuji. I have asked friends from Fuji, Konica and also instructors from Chiba university in Japan. None of them have ever heard of Ryuji Suzuki. I never heard of him at Kodak, and yet he states that he knows a lot of about how we all did things. Oh well. What he describes must be from literature freely available to others in textbooks, but almost certainly not by inside information.

George T. Eaton, in a 1957 book, published by Kodak called "Photo Chemistry in Black and White and Color Photogrpahy" goes through this entire process and describes it in detail with pictures.

I encourage you to get this book. It contains no emulsion formulas, but does include some of the only pictures of early making and coating at Kodak. I include three here to encourage you to get a copy of the book.

This picture clearly shows the method of making emulsions in the plant at Kodak from early years until the early 60s when the first automation started. The automation advances continued through the 80s with the introduction of full computer control. All products up till about the 60s were made with no or minimum control and after that with minimum early methods until the full automation in the 70s - 80s. That level of control continues until today.

You can clearly see that there are 3 'jars' used for addition which may contain 4 ingredients or more, and the operator is dumping in an ingredient from a can in the left hand picture.

In the coating picture, on the right, you can clearly see the rising web of film coming off the coating hopper which is below the guard and out of sight. You wouldn't see a picture of that anyhow.

Enjoy.

PE

Alex Hawley
04-27-2007, 07:22 PM
I found this in the Polaroid website FAQ:


Question: How does printing from a Polaroid negative compare with printing from a conventional negative? What light source gives the best contrast when printing portraits?

Answer: A properly exposed and processed Type 55 negative has many of the same characteristics as a conventional Panatomic-X negative. And although the range of the Polaroid negative may be somewhat narrower, printing on a slightly higher grade paper -- No. 3, as opposed to No. 2 -- may negate any apparent difference. In addition, you'll find little difference between enlargements made from condenser enlargers and those made from diffusion enlargers.

Bold font and underlining added for emphasis. I found this by searching for "Type 55" in the FAQ on polaroid.com

Doesn't fully substantiate that the Type 55 negative is Panatomic-X but does lend some credibility to the belief.

PE, correct me if I'm wrong, but I believe Panatomic-X was originally developed for aerial reconnaissance. Could it be that through the miracles of government contracts that Polaroid also made the stock and Dr. Land somehow finagled the rights to use it in Type 55? Or perhaps Polaroid developed the emulsion and Kodak produced it mass quantity?

Ryuji
04-27-2007, 07:37 PM
Alex,

Panatomic and Panatomic-X films existed since 1930s in roll and sheet formats. If you want I can even show the edge notch code for sheet films from that time. Both Panatomic and Panatomic-X were rated daylight group number of 24 and tungsten group number of 16 in Weston film speed rating.

Just prior to WW2, Eastman Kodak had Super XX, Verichrome, Panatomic X, N.C., in small (rolls and packs) formats, Super X, Super XX, Plus X, Panatomic, Panatomic X and Microfile (this is a very slow film) in miniature format. They had commercial films in even greater lineup, including Tri X Panchromatic, Ortho X, Super XX, S. S. Ortho portrait, S. S. Pan, Portrait Pan, Commercial Pan, Par Speed Portrait, Panatomic X, Commercial Ortho, Commercial. They also had more than dozen types of emulsions for plates.

In reality, these products received occasional improvements and emulsions of that time are most likely different from the emulsions we know from past few decades.

On the other hand, Polaroid Type 55 was introduced in 1961. Land demonstrated a single step instant photography in 1947, followed by Type 40 sepia of 1948 and Type 41 b&w of 1950, both at speed of 100.

Alex Hawley
04-27-2007, 08:00 PM
Good info Ryuji and thanks. No need to get down to the notch codes for me. Was the thin base in use on Panatomic in that early period? It was my understanding that the thin base was the part that was developed specifically for the aerial recon purpose. That enabled winding substantially more film onto the spools, and provided a tougher yet more flexible base for the power driven and high transport speed mechanisms.



Just prior to WW2, Eastman Kodak had Super XX,

That possibly busts another legend; the one that says Super XX was captured from the German military in WWII.

Ryuji
04-27-2007, 08:17 PM
Was the thin base in use on Panatomic in that early period?


That I need to check before answering. I've not dug very deep in the history of film base manufacturing, but in 1930s film base was most likely cellulose diacetate or older technology. Of course dimensional stability is vastly inferior to modern sheet films.

Thin and tough film base that had good dimensional stability had to wait until polycarbonate and other plastic film base technology, which didn't last for long before replaced by polyester film base. These are post war era.



That possibly busts another legend; the one that says Super XX was captured from the German military in WWII.

Well, it is very plausible that Kodak reformulated their negative emulsions around 1950 using technology that Britain and America took from Germany. Koslowski of AGFA Wolfen lab (AGFA had a research lab and film plant in Wolfen and paper plant in Leverkusen at that time) developed famous gold sensitization around 1936, and Wolfen lab also had a number of organic compounds that were useful in sensitizing and stabilizing emulsions, most of which weren't known outside AGFA until BIOS and FIAT investigators went in there. These pieces of information were published in classified government reports by both British and American teams, which were declassified after. Kodak people in Rochester were very active in investigating the combined effects of reduction, sulfur and now gold sensitization in various emulsions and some of them got published c. 1950. After 1945 but before the end of 1950s, both Kodak and Fuji film speed doubled, when compared with the previous emulsions of same grain size.

I think it is quite true to say that all current camera negative emulsions utilize the technology was taken from AGFA Wolfen. Some compounds I see in those BIOS and FIAT reports are still quite common in emulsion making today. Some are improved and still used. Many others are not from Wolfen but inspired by what they learned from them. Some other compounds are also very commonly used in developers for automatic processing machines.