Developer secrets

Discussion in 'B&W: Film, Paper, Chemistry' started by alanrockwood, May 3, 2009.

  1. alanrockwood

    alanrockwood Member

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    Just a quick question. Are there any real secrets in developer formulas? By that, I don't mean things not known by the general public. I mean, do all the major companies know the formulas of the other company's developers?

    I am assuming that most companies have liquid chromatographs, mass spectrometers, and other analytical equipment available that would allow them to analyze competitive formulas.
     
  2. Ian Grant

    Ian Grant Subscriber

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    It's extremely difficult to fully analyse and determine whats in a specific developer, but you can get quite close. However a great many developers are found in Patents or Scientific Journals anyway. So for instance Ilford had to use a different approach when formulating Ilfotec HC (& LC) to get around the patent for HC110.

    Ian
     
  3. Photo Engineer

    Photo Engineer Subscriber

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    There are specifics of manufacture that are not widely known in the trade. Kodak has a lot of trade secrets that they do not make public. And, to add to that there are chemicals in use that are not publicized or techniques that are very unusual. Along with that are formulas that were never released to the public.

    We cannot duplicate some of this outside of a large industrial facility. One specific example is making HC110 syrup. This is done by charging a specific quantity of Sulfur Dioxide gas into TEA/DEA and then mixing it with another batch of TEA/DEA that has been charged with HBr gas. This supplies the Sulfite and Br ions but in an inactive form until the syrup is mixed with water. Another example is the preparation of D76 or Dektol powders in which the two main ingredient classes are separated from each other by an encapsulation technique that is quite confidential.

    PE
     
  4. Oren Grad

    Oren Grad Subscriber

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    Both of these sound like techniques to enhance the keeping properties - very important for a retail product that is likely to sit on the shelf for a while - rather than anything that affects the sensitometric behavior of the fresh product. Is that right?
     
  5. Photo Engineer

    Photo Engineer Subscriber

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    It has two effects. It gives very high stabilty and also allows for very great concentration to make a very concentrated syrup. This means that you are not shipping water, but rather almost 100% active chemistry. However, this is almost impossible to do on smaller scales.

    It has no effect on sensitometry as the effective result is that the SO2 becomes the equivalent of Sodium Sulfite and the HBr becomes the equivalent of NaBr in water.

    PE
     
  6. Ian Grant

    Ian Grant Subscriber

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    As Ron says different companies have there own approaches so while ID-11 & D76 are similar, they were once identical. Likewise D72 - Dektol and Bromophen which are eqivalents, the liquid version of Dektol differeing from the powder, one usingMetol the other Dimezone.

    Companies weren't/aren't interested in making exact copies of competitors products rather being able to offer a suitable alternative. ID-11/D76 is perhaps the only exception and was a 1930's developer equivalent of Open Source software, manufactured by just about every company to allow consistent processing of Cine films.

    Ian
     
  7. Photo Engineer

    Photo Engineer Subscriber

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    Yes, Ian is correct. I might add that Liquidol and Dektol act quite alike in sensitometry and image tone, with just a slight iimprovement in shadow detail with Liquidol, but they are formulated quite differently. You can get to the same place or to a roughly similar place by different routes.

    Liquidol could be changed to be exactly equivalent to Dektol by tweaking. Bill and I thought the results in the shadows were good enough as they were to merit the stamp of approval. Other properties are different though, but this is not the venue for this sort of discussion.

    PE
     
  8. Ray Rogers

    Ray Rogers Member

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    ???
     
  9. Ray Rogers

    Ray Rogers Member

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    What is the sensitometric equivalent to "a slight iimprovement [sic] in shadow detail..." ?

    Higher shadow contrast?
     
  10. Photo Engineer

    Photo Engineer Subscriber

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    Lower contrast in very high density areas allows you to see more detail in blacks and near blacks. Higher contrast reduces the difference between blacks and therefore decreases detail. This may appear counterintuitive at first glance, but it is true.

    PE
     
  11. Nathan Potter

    Nathan Potter Member

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    Whoa! This is counterintuitive. I've recently had a renewed interest in divided developers owing to their ability to linearize the sensitometric curve at the low negative density end. This seems to clearly provide for greater discrimination of detail in the shadow region of the print. Maybe I've not grasped the suttleness of your comment above. Perhaps you are implying that the lower gamma in the tail of the sensitometric curve (the first derivative of that curve function) when taken a second time yields a steep slope and thus a greater shadow discrimination than would be intuitively expected. Interesting thought but I'm not sure I'm grasping your intent very clearly.

    Nate Potter, Austin TX.
     
  12. Photo Engineer

    Photo Engineer Subscriber

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    Well, the shadow detail of a print takes place in the shoulder end of the paper curve. With lower contrast or extended scale there, you see more before total blackness takes place. So, a slightly elongated shoulder enhances shadow detail. Even though the mid scale and toe of the paper may be the same, you can see more depth in shadows if the shoulder scale is extended. This is due to the fact that paper has a limited scale due to multiple internal reflections which confounds intuition by means of physics. :D

    PE
     
  13. Alan Johnson

    Alan Johnson Subscriber

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    There are few new non-specialist developers.One is Ilfosol 3,for which Ilford have a safety data sheet.One could guess that it leaves out ascorbate and perhaps dimezone.
    There are few photochemists left in B/W research.I believe Ilford have about 12, Kodak and Fuji numbers would be interesting to know.
    But I daresay there is less effort goes into new developer secrets than might be inferred from the last part of the quick question.
     
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  15. Nicholas Lindan

    Nicholas Lindan Advertiser

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    The greatest developer secret of all time: There are no developer secrets.
     
  16. Ian Grant

    Ian Grant Subscriber

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    There are/were and unfortunately most will be lost.

    Companies like Johnson's in the UK made great developers, so did many other smaller companies now long closed.

    Kodak (UK) used to sell a High Definition developer not manufactured or imported by Eastman Kodak in the US/Canada that remains a secret but it competed with other high acutance developers like Ilford Hyfin and Johnson's Definol.

    Older developers like Rodinal took on a new lease of life with the advent films like AP100/APX100 and Tmax and experimental developers that were found to be unsuitable for old style thicker/unhardened emulsions.

    A good example is how Pro developers have made a big comeback in recent years through the work of Gordon Hutchins and Sany King

    Others are working to revive PPD - Glycin, Metol, Phenidone & Pyrocatechin combinations. This was an area Johnson's were particularly strong in.

    Ian
     
  17. Ray Rogers

    Ray Rogers Member

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    How about Metering Secrets?

    I'd like to build a cumulative light meter...
    something that will just tell me how much exposure has been given....

    Could you suggest anything I might be able to put together myself?

    Ray
     
  18. Photo Engineer

    Photo Engineer Subscriber

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    I have to agree with Ian and disagree with this statement.

    There are many developer secrets never revealed by the major companies or only revealed via patents.

    Even then, the data is obscure and use arcane to the outsider. As I said before, I could teach a full workshop on just this subject alone. And, as I said before, I am not the best qualified to do so. Grant Haist and others would simply overwhelm you with information.

    PE
     
  19. Keith Tapscott.

    Keith Tapscott. Member

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    Would that be to protect the developing agents from the other components in single-powder packages?
     
  20. Photo Engineer

    Photo Engineer Subscriber

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    Yes, and it is the reason why you cannot really mix a partial packet of powder. The alkali is in one type of packet and the sulfite and developing agents are in another. It is kind of like having a 12 or 24 hour release medication that is a mixture of things. Except here, the release takes place in the hot water.

    PE
     
  21. Kirk Keyes

    Kirk Keyes Member

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    I'd like one of these too. Ray - start another thread and I'm sure Nicholas would be up for talking. I'd can see a home made one with a Aurdino-type controller, a small LCD readout, battery, and sensor. Make it incident to simplify the design.
     
  22. billtroop

    billtroop Member

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    Re exposure, I have one 'secret'. I still treasure a note I had from Dick Henry mentioning the discussions he had with Ansel Adams after I broke the news to both that exposure meters are (and since the early ASA standards, always have been) calibrated for 12% grey, not 18% grey. Somehow this important fact had eluded virtually every single popular American writer on photography for decades, but it had been revealed by the UK writers Dunn and Wakefield, and I subsequently confirmed it with one of Kodak's great experts on sensitometry, C. Nelson.

    Re developers, I have one secret that I learned from Bob Schwalberg, the late, great photographer and writer for Popular Photography, during the time he was testing some of my early formulas.

    It's so simple,

    yet nobody ever does it

    because it's annoying

    and - - - myth-breaking.

    Are you ready?

    It's just - - -

    whenever you are testing a film developer

    always, always, always, always,

    always test it against D-76 1:1.

    D-76 is the eternal and immutable gold standard for b/w. Simple as that. Do you think you are achieving something different? better? etc ? Make sure you have comparison negatives with D-76. It's the only way to make sure you really are getting something notably different.

    Now, as we all know, D-76 can be variable in use, upon storage of several months or upon excessive aeration when mixing. So mix it slowly and always mix it fresh. Or use D-76H.

    Speaking of D-76H, I have been discussing that with Ron lately, and he thinks I should change the formula, but that's a subject for the future. For the sake of this argument, let's just stick to D-76 made from scratch.

    And, it should go without saying: working with D-76. Really get to know it. Understand what it will provide for every film you work with. That way you'll have a secure basis for making informed comparisons with other developers.

    Simple. Annoying. But it's the best secret I've ever learned.
     
  23. Kirk Keyes

    Kirk Keyes Member

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    Shouldn't that be XTOL 1:1 nowadays?

    Doesn't Sylvia claim it's the best alround developer these days?
     
  24. Photo Engineer

    Photo Engineer Subscriber

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    AFAIK, Kodak still uses D-76 straight for release testing of films.

    PE
     
  25. sanking

    sanking Restricted Access

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    Another secret with developers is that you will often get very different results with type of agitation. Rotary agitation, as in Jobo or BTZS type tubes, gives very even development, but sharpness is often increased by letting the film sit for a while in the developer with no agitation. And of course, the extreme of that is pure stand development.


    Sandy King
     
  26. billtroop

    billtroop Member

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    Kirk, just because XTOL is 'best' -- which some would agree with and some wouldn'n-- doesn't mean it makes a good standard. A standard must be published and fairly well understood by everyone. Only D-76, in spite of its faults, fits the bill. I don't think a phenidone/dimezone developer will ever be considered standard because it can't, unlike metol, function as a single-agent, normal contrast pictorial developer, and because its interaction with HQ is still not entirely understood, much less its interaction with ascorbate or anything else.

    Sandy, you are right to focus on agitation because this is where a lot of testing falls down. For example, Altman/Henn's influential paper on acutance developers is hopelessly marred by the fact that they used a continuous agitation system for their automated testing. Dickerson and Zawadzki, decades later, had a much more sophisticated system that allowed for consistent intermittent agitation. I do believe that some sort of standardized intermittent agitation should be used in all developer testing that hopes to be standardized. Unless, of course, you're testing agitation itself.