Emulsion Makers Book Club, Selection One: Photographic Emulsions

Discussion in 'Silver Gelatin Based Emulsion Making & Coating' started by dwross, Dec 8, 2010.

  1. dwross

    dwross Subscriber

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    Following up on a wistful thought by Holmburgers, I'm posting a link to a book I finally finished scanning and posting to The Light Farm last night. Good timing!

    http://thelightfarm.com/cgi-bin/pho...curpage=1.0&dispsize=Large&changesize=Smaller

    The Photographic Emulsion is a compilation of a series of monographs written between the late-1920s and the mid-1930s, by Carroll, Hubbard, and Kretschman. The table of contents speaks for itself. It's a classic and a wealth of information.

    If we were to treat this like a brick and mortar bookclub, we'd start at the beginning together and discuss the book as we progressed together. I have no idea if that would work here. No harm in trying. At any rate, happy reading.
    d
     
  2. wildbillbugman

    wildbillbugman Member

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    Hi Denise,
    Let me be the first to singe up for your "Book Club". It so happens that I have pulled my "ham-string"and am now obliged to sit on my butt for a while. So I will read the book and report back with comments, questions,etc.
    Bill
     
  3. holmburgers

    holmburgers Member

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    Wow, it's great that you've scanned this book! Unfortunately I am not quite into making emulsions, but I love to hear what you emulsifiers are up to.

    Here's a question whose answer might lie in this book, but... what sensitizer and/or how would you panchromaticize one of the commercially available liquid emulsions? This kind of discovery could have far reaching consequences for all sorts of alt processors. Any ideas?
     
  4. Jerevan

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    I don't understand much (or rather have little idea of the implications of the various schemes presented) but I am going to read anyway. Some things will stick, eventually. I assume the speed mentioned in fig. 1 and 2 (page 18 - 19) is not ASA/ISO?
     
  5. wildbillbugman

    wildbillbugman Member

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    Hello to all,
    Somewhat high on Oxycodone, I have read chapter 1 . The first thing I noticed is that the initial swelling of the gelatin is carried out in a solution of KBr, rather than in distilled water. I never tried this. But, given the fact that, in 2010, the chemistry of gelatin is still not fully defined, I wonder if there could be a difference between swelling the gelatin in water, then adding KBr and doing it the Author's way.. There could be a difference in the way in which the Br is dispersed along the strands of gelatin. This might lead to a difference in rate of emulsification and in ripening.
    Pure speculation!
    Bill

    But this is pure speculation on my part.
     
  6. Photo Engineer

    Photo Engineer Subscriber

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    There does not appear to be any difference between the swelling of gelatin + KBr or the swelling of gelatin then addition of KBr except for the time it takes to do the swelling. KBr slows down the swelling of gelatin!

    PE
     
  7. Photo Engineer

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    Some additional thoughts expressed before.

    1. The book does not clearly state when active or oxidized gelatins are used for the makes. This makes speed, fog, and contrast variations difficult to evaluate, especially if you move on to the sensitization chapter.

    2. The use of colloidal Iodide in the sensitization chapter was in large part misunderstood in that day and age. The Iodide effect was a bit different than what they observed and is used today in most all Kodak emulsions, as the second step rather than at the end of the make due to the latest revised understanding. And, many emulsion makers today say that adding Iodide like this should cause renucleation, but it actually does not if the process is carried out properly.

    So, I can say that for beginners, this is a good book but rather dated with information that has changed over the years with better explanations and also I can say that this book starts out by leaving a lot of things out. Burt Carroll was a friend in my early years at Kodak, and just after he had retired. I have had a chance to discuss some of these things with him in the 70s. I think that he would write a totally different book today. I wish I had the resources to write a fully revised edition of his book.

    The accepted wisdom today is to dissolve salts in the kettle and add dry gelatin. Then stir while raising temperature. OR....
    Add dry gelatin to cold water and stir while raising temperature, then add salt. The latter method is quicker and is currently used. No ions but K, Na and NH4 are used as halide salts when making emulsions. All other positive ions in the kettle as halide salts have bad effects except for a few used at low concentration such as Cd, Cu, Hg, Ir, Os and Rh. These are listed in decreasing useful concentration and they do not work equally well in all emulsions. Cu and Hg are used mainly for toning to get warm toned emulsions.

    PE
     
  8. dwross

    dwross Subscriber

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    Actually, you've precisely hit on the value of reading technical historical literature. Starting from the implications, and then circling back to specifics/facts, ideally coupled with some hands-on lab work, is exactly how historical sciences are best understood and recreated.

    Re 'speed': The concept of speed, as we know it as a set of standardized values, is essentially meaningless with 'color blind' (i.e. sensitive to only UV light) emulsions. It wasn't until the 1930s and 40s that the research was done on emulsion sensitivity that was adopted by the American Standards Association. Until then, there were a half dozen different 'standards', but it is almost certain that Carroll and Hubbard were using the system of comparative speeds, based on gaslight papers as '1'.

    From the Focal Encyclopedia of Photography, 1958: Material/Relative Speed
    Contact papers and contact lantern plates/1
    Slow chlorobromide papers/10-20
    Fast chlorobromide papers and warm-tone lantern plates/50-100
    Bromide papers and bromide lantern plates, positive films/100-500
    High-speed pan film or plate/around 100,000.
     
  9. dwross

    dwross Subscriber

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    Poor Bill! Ouch. I can't even imagine reading this stuff on painkillers. On the other hand...maybe that's precisely the way to read this stuff.:D
     
  10. Photo Engineer

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    Technical historical literature is fine unless it is wrong or misleading due to later advances in science. Unfortunately, Mees begs the issue as do Mees and James. No updates to emulsion technology were made in the literature.

    Mees says: One omission in the book requires explanation. A book on the theory of photography should contain a chapter on emulsion making, discussing various methods of procedure and their effect upon the finished product. The author's knowledge of this subject has been acquired in confidence, however, and he is not entitled to publish the material with the frankness which alone would justify publication.

    No one has done this, ie. publish a full disclosure on emulsion making. Even Haist has published an emulsion formula with deliberate omissions in it. This is endemic in the entire literature and the readers must be aware of this. I must add to this list of Mees and Haist, the following: Wall and Baker among others including the aforementioned author and referenced in the OP.

    PE

    PE
     
  11. dwross

    dwross Subscriber

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    I am very much looking forward to the first graduate student who researches the history of gelatin with the characteristics of the myriad of brand names available at one time. Until then, for my purposes and interests in photographic emulsions as an historical process, I'm not finding the 'gelatin issue' a stumbling block.

    I would hope that Burt Carroll would write a different book today! That's the nature of science. If you wrote a revised edition, I would hope that someone would revise it 80 years from now :smile:. And each edition would be a valuable addition to the library of an historian of emulsion making. I have three editions of Fundamentals of Photographic Theory by James and Higgins. All of them have valuable information. The same is true for the four editions of The Theory of the Photographic Process, first by Mees, then by Mees and James, and finally by just James.

    'And, many emulsion makers today say that adding Iodide like this should cause renucleation, but it actually does not if the process is carried out properly.'
    That sounds like it's a book all of its own. Actually, that's the kind of opaque statement that's a pretty strong motivation to dig into the literature.

    I'll add a short note for the non-chemists who would like to join this 'book club'. Halides (at least the ones we care about) are chloride (Cl), bromide (Br), and iodide (I). They combine with potassium (K), sodium (Na) and NH4 (ammonium ion). The combinations are 'salts'. NaCl, sodium chloride, is common table salt. The halides combine with the silver in silver nitrate (AgNO3) to form silver halides, sometimes noted as AgX. The silver halide is the photosensitive constituent of the emulsion.
     
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  12. Photo Engineer

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    Denise;

    To start with, if I wrote a book today (I am as you know) it probably would not be UPDATED in the future due to the lack of R&D on analog. This is a sad note.

    I spent the day at GEH with many of the people there discussing conservation issues and recreating historical processes. There is too much for one person to cover, so the history of KI added to emulsions will have to take a side line to the huge overall history of Analog, sorry to say.

    Added to the halides you mention there are Fluorine and Astatine. Now, these are not used, but why not would iin itself cover a chapter in a book as would the reasons for not using Calcium, Magnesium and other salts of halides. This is not trivial, it is more than a lifes work of many individuals. And, few are interested. This is, in part, hard core chemistry, and the early 20s is soft core in terms of today's knowledge. So, as things move forward, Phlogiston theory is forgotten. :wink:

    PE
     
  13. Hexavalent

    Hexavalent Subscriber

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    Astatine: very very expensive self-exposing emulsion :smile:
     
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  15. Photo Engineer

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    Astatine, arrested for exposing itself!

    PE
     
  16. holmburgers

    holmburgers Member

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    Fascinating.... what more can you say about these exotic halides? 20 words or less will do (or more if you please!).

    It's sad that knowledge will be quite literally lost because of the way in which our culture is organized. EK & Fuji have taken the making of photographic emulsions to nearly theoretical limits of perfection, wouldn't you agree? And yet, due to corporate interests & proprietary knowledge, that information will die with these companies. When it's all said and done (like 100 years from now), will this information be accessible at all?
     
  17. Hexavalent

    Hexavalent Subscriber

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    Astatine is a radioactive halogen with a short half-life (hours). Extremely rare, expensive and unstable.
    AgF is very water soluble, unlike the 'other' Silver halides, and is a bit too reactive to be useful.

    More than 20 words, and probably worth less than 2 cents :smile:
     
  18. holmburgers

    holmburgers Member

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    Not at all, very interesting!

    Quote, "Astatine is currently the rarest naturally occurring element, with less than 30 grams estimated to be contained in the entire Earth's crust."
     
  19. dwross

    dwross Subscriber

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    Your last question is really two separate questions. "This information" is neither homogeneous nor linear. Silver gelatin photography covers 130 years (and counting) of science, art, and technology. The high-tech end of the timeline is almost certainly safe. Kodak's failure of vision is probably the best thing that could have happened to analog photography. Other companies can finally get their feet in the door. George Eastman was secretive and monopolistic in the extreme. The corporate environment he fostered was semi-loony. Secrets for the sake of secrets. A good example of that mindset can be seen today in the Wikileaks broohaa. Why in the world was most of that junk secret?

    Anyway, Ilford seems committed to silver, and the Eastern European and Chinese companies are really coming into their own. I don't see them going away, at least in the aggregate.

    What may be endangered is handcrafted silver gelatin. It was never actually a handmade product for more than about ten years. And here's the important point: It was totally commercial propaganda that convinced photographers that they could no longer make their own materials -- and propaganda became fact. After about 50 years of technological advancement, it was true that the home darkroom could no longer make the same products as Kodak, but that still leaves a lot of great recipes available to us, each with a distinctive beauty and the satisfaction of the handcrafted product.

    The next thing here is hard to say, or at least to say without butting heads with a couple of regulars to this forum. If we want to learn to recreate excellent emulsions, those within our technological reach as handcrafters, we absolutely can. But, it will take staying focused and on point. There are only three halides important to photography. Discussing the others, or pretending that understanding their chemistry and physics is even remotely necessary to making an emulsion, is nothing but a meaningless digression. 'Soft core' chemistry is more than good enough to make gorgeous emulsions. I am not a chemist, and I'm printing a portfolio right now that has me proud-to-busting. If you're really interested in making emulsions, please don't be discouraged or deflected by the nay-sayers and pessimists.
     
  20. wildbillbugman

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    Surely (?), EK and the other major players in emulsion research have kept records of all formulas and other aspects of their research. Although they will not release these records in the foreseeable future,100 years from now they may be made available to those interested. I hope that these companies don't behave like a Government and burn all the evidence.
    There is hope for analog. A giant solar flair could take out all the circuit boards in the world, sending us all back to 1850.
    Today,I will read Chapter II. I have nothing better to do.
    Bill
    Bill
     
  21. wildbillbugman

    wildbillbugman Member

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    "Knowledge is Power",only if it is exclusive!
     
  22. holmburgers

    holmburgers Member

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    I'm not discouraged in making my own emulsions, but what I'm saying is that will a group of individuals ever be able to achieve the perfection of say, the slide films of Kodak/Fuji? It seems like the R&D necessary to produce something with that high of quality is unattainable today, without the market incentive and the years of work towards these excellent products.

    All I'm saying is, can the patents and published information lead to such a result if an individual or smaller operation took up the task?

    A 100 years from now, will they publish this information? IDK, but no one even knows how to operate the original autochrome machines, as an example. Perhaps if they had left detailed instructions for the public, we could.
     
  23. Photo Engineer

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    What I have tried to say in my posts here is that the books out there have been severely censored either by the authors or the companies that they represent. In addition, no definitive work has been published in just about 75 years that explains emulsion making. Therefore, although you can gain a sense of what is going on, you can spend a lot of time trying to make something that works well in your home lab.

    If you take the basic Baker SRAD emulsion, which he calls "high speed", and make it today, it comes out with an ISO of about 6 - 12 because all gelatins sold in the western world are inactive, but if you modify the formula to use the methods of Sheppard et al, you can get ISO 40 - 80, which is what Baker probably intended. Well, the same goes for all other emulsion texts.

    It is like reading a book on surgery from the 1800s. Not wrong, but clumsy and with many misinterpretations of observed effects.

    I have been trying for 5 years to reduce the old emulsions to modern formulas, and to tack on modern techniques and modern formulas and organize them. If it had not been for the secrecy though, I would not have to be doing this. BUT, (and this is a big but), all of the techniques are out there in patents for all to see! Understanding is another thing, and capability to carry out the instructions is another. And thus, the modern core shell t-grain formulas are there as is the entire structure of Ektar put forth in one patent for all to see. I've posted the patent # for all to see in another post rather similar to this.

    So, given the technology and the desire does not give you the ability to do top-of-the-line work, but it will help you understand, and what I am writing up will carry this much further for the average darkroom worker.

    PE
     
  24. wildbillbugman

    wildbillbugman Member

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    Holmburgers,
    Having worked in R&D for several large companies, I know that a great deal of emphases is placed on Documentation. I think that, in the days of Autochtome machines,things were much looser. Therefor proprietary information was much more easily lost than it has been since,say,1960.
    Bill
     
  25. holmburgers

    holmburgers Member

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    Well that is reassuring, and I think that what you're doing Ron is very valuable. But isn't it true that patents don't discolose the "trade secrets"?

    Anyways, I'm straying from the topic, but I just would hate to see color films not being manufactured by anyone... the technology is just too miraculous to forget about it IMO.
     
  26. Photo Engineer

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    The trade secrets involved are those related to how exactly the emulsion is made and coated. So, although the entire formula may be given, the mixing speed, mixer design, UF hookup and the rate of exchange are a number of things that are glossed over by saying "it an be repeated by one skilled in the art". This last part is what I am doing in my home darkroom, and I'm doing it from memory.

    Whether the interest is there to use it is another matter. I doubt if anyone is willing, and so in the future I would say that we will have the following: A blue sensitive emulsion with an average ISO of 12, a contact print and very slow enlarging paper with a grade of 2 or thereabouts and that is it. Much more is possible. What is possible is an ortho or pan emulsion with speeds up to 400, and a VC or fixed contrast paper for contact and enlarging with current speeds. A simple color film and paper are also within the reach of the home worker. But, I see little serious interest in the more advanced possibilities, and just mild interest in the simpler options.

    PE