Film/developer testing at Kodak and Ilford

Discussion in 'B&W: Film, Paper, Chemistry' started by michael_r, Oct 11, 2011.

  1. michael_r

    michael_r Subscriber

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    Hopefully PE and Simon will write in on this one.

    Over the years as I've tested and practiced with various film/developer combinations, it always struck me how time consuming it is, and how much care is involved in carrying out exhaustive experimental testing leading to meaningful, repeatable results. It requires much repetition, and careful monitoring of variables.

    I've often wondered, how exactly was this carried out at companies like Kodak and Ilford (in the days before research stopped of course). For example, when a new developer is formulated: never mind the laborious work of testing during the formulation or R&D phase, but what about even after that, when the formulation is complete and developing times and agitation scheme instructions need to be determined for a whole list of films, in different formats? How was this actually done? In the heyday, were there actually teams of people developing film all day in small tanks, large tanks, roll film, sheet film etc etc over and over again? How many times would something be repeated until it was determined to be an experimentally significant result? Do EK and Ilford actually have facilities where people spent most of their time developing film under controlled conditions, at all the different temperatures, for different contrasts, dilutions, and on and on?

    And what about all the research papers from people like Henn, James etc etc you read about referenced in summary books like Anchell/Troop? Did these big guys have employees working for them testing materials all day? Would those people be grad students, or junior employees? I think I would have enjoyed that sort of grunt work actually. :smile:
     
  2. ic-racer

    ic-racer Member

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    B&W development times are just suggested starting points, so I don't suspect they labored too much over it. Color was probably a different situation.

     
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  3. michael_r

    michael_r Subscriber

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    In my experience the suggested times vary from pretty good to wildly wrong in both Kodak and Ilford literature, but I still find it hard to believe they didn't work hard on it. The only reference to this sort of thing I have in my books appears in Anchell/Troop on the subject of XTOL times. Apparently, at least for that particular developer, there was a lot of rigorous testing, directly supervised by XTOL's formulators. But perhaps in other cases you are right - maybe the instructions are based more on extrapolation rather than brute force testing.

    But even if we go beyond instruction sheets, I'm also referring to testing done to support all the research papers that came out of these companies regarding everything from sharpness to grain, contrast, etc etc.
     
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  4. pentaxuser

    pentaxuser Subscriber

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    If you look at the info on a "newish" developer like Xtol it seems pretty extensive to me, covering a large range of films and rotary processing. The impression I get is that Kodak was pretty thorough in its research.

    Last time we visited Ilford, there was still an active research dept and if its ongoing strict QC is anything to go by I'd be surprised if Ilford was in any way "winging it" in terms of films and developer information.

    Having said that I note that one film in particular, one of its latest, namely D3200, has a reputation for needing the times for the next speed up.

    I have no idea whether there is a similar Kodak film for which user developing experience diverges from Kodak's recommendation.

    pentaxuser
     
  5. michael_r

    michael_r Subscriber

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    Don't get me wrong I'm not talking about quality control on the products themselves. Ilford and Kodak products are first rate.

    I didn't want to make this about how right or wrong things like suggested developing times are, but since you asked, I've personally experienced some of the suggested starting times for both Ilford and Kodak products being way off. I'm happy to share my own results, but I'm not sure if I want the thread to go in that direction because developing times can vary significantly from person to person based on how well temperature is controlled, different agitation schemes, accuracy of measurements, testing methodology and on and on. That's why even when my personal times are way off I hesitate to say the suggested times are "wrong".
     
  6. MattKing

    MattKing Subscriber

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    In addition to all their lab testing, Kodak used to make fully equipped darkrooms (both colour and black and white) available to their employees. All the equipment and chemistry was supplied.

    So they had a built in testing force available as well.

    EDIT: at least at their major lab sites (like Toronto in Canada)
     
  7. Michael W

    Michael W Member

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    If you watch the 1950s Kodak industrial documentary "How Film is Made" you can see them testing some film and plotting an H&D curve. You can watch it via the APUG media page.
     
  8. Stephen Benskin

    Stephen Benskin Member

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    The manufacturers post curves. The recommended "times" are based on a set of conditions that are usually listed. For Kodak, it is either CI 0.56 or 0.58 which is normal for a grade two paper with a diffusion enlarger under average conditions. If you're conditions are different, check the CI / Time curves.

    The manufacturers aren't wrong. The times just might not be right for your conditions and the way you work.
     
  9. Mike Wilde

    Mike Wilde Member

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    There was a good discussion of the testing done in the early years of Kodak research in a non technical retorspective 'from Wratten to Ektachrome' or something like that.

    It was written by committee on retirement or the first director of Kodak research labs. whose name escapes me at the moment. Not Mees, but his presicessor I think.
     
  10. michael_r

    michael_r Subscriber

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    Stephen, that's why I didn't want to make this a discussion on how "right" or "wrong" the published instructions are. I'm interested more in how the actual testing work was done from a manpower perspective.
     
  11. terrywoodenpic

    terrywoodenpic Member

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    certainly from the 50's to the 80's
    Professionals could get Data sheets from both Kodak and Ilford on every product.
    They were incredibly detailed and ran to many pages. Developers were tested with all of their own films and most leading brands. There were graphs, characteristic curves and data covering every aspect from gamma to density, dilution, agitation temperature, response to wave lengths of light, sharpness grain characteristics.
    in fact every aspect you could imagine. nothing was left to chance.
    The figures were accurate in the testing conditions specified and were repeatable.

    Professional sheet colour film came with testing data for that particular batch. and gave correction factors for exposure and colour away from the normal. Particularly for long exposures.
     
  12. jnanian

    jnanian Advertiser Advertiser

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    don't forget people like jerry katz at photo lab index ...
    he and others did exhaustive tests on films, papers and developers
    it seems that it was not only the manufacturer but a lot of people
    "in the industry" did a lot of tests ( including labs, professional photographers &C )
     
  13. Simon R Galley

    Simon R Galley Subscriber

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    Dear Michael R

    What is correct and what is incorrect ?

    Firstly, at HARMAN we have a technical service department this covers QC Complaints, new product evaluation, competitor product evaluation and technical writing for for photo as well as inkjet. Also under the technical service head is the ILFORD processing and lab service.

    We also have a QS Department or quality services department, they do all the online QC testing, processing, printing etc for the actual QC Before and during manufacturing.

    For example :

    Before : All raw materials are tested against the specifications before they can enter the manufacturing process.

    Manufacturing : Film and Paper is coated : Multiple samples are taken and processed from every parent roll and evaluated against the specifications. This is for a huge range of performance factors both physical such as adhesion as well as for its sensitometric performance, The film and paper is then 'conditioned' or 'rested' to harden and further samples are taken, after it has passed those tests the film and paper is passed for converting or 'finishing' further samples are then taken and processed from the finished goods to test the finishing process etc, then samples from every finished batch are taken and stored ( for 5 years ) so they can be processed at anytime in the future against any QC enquiry. All our chemical products are also tested.

    But I am sure your interest is in our product evaluation...

    We have our own darkrooms, lots of them, R&D may do their own work and processing, only when it is a product would tech service 'evaluate' or be 'given' the product, it is their job to write the specifications and user guides ( clue in the word there! ) they evaluate from a host of different applications, they would then and only then pass the the film as fit for purpose and launch..

    eg

    Take film ( last new film made was the two new KENTMERE emulsions ).

    Photography, set procedures as well as random, indoor, outdoor, low light, bright light etc, etc, etc,
    Manual processing,including different tank types, single film, multi film, mixed film, machine processing, push processing, latent image performance, physical performance heat and cold testing, different agitation methods, reticulation, different developers - not just ours, different temperatures on and on and on,

    Tech service do all of this! and the sensitometry and produce the TI or Technical Information sheet.......it does take time.

    They then produce a set of processing times ( in a wide range of developers, not just our own, but by no means exhaustive ) set to to a prescribed standard to produce an average density neg.

    For sure, many people 'disagree' with our processing times, that is absolutely fine, they are a GUIDE, I have seen so many people on APUG say find a film, find a dev, find a process regime that works for you and stick to it and how right they are in my opinion, you do not have to have just one, just make sure you do the same thing every time, I use a lot of DELTA 3200 hand devved in DDX, I also use HP5+ devved in ID11 as well... I have the process written down and do it the same every time. No pre-soak high dilution, slowish dev, 10 seconds agitation per 60 secs of development, then chuck the dev.

    But most important of all in testing : Customer evaluation :

    During the testing or pre-launch stage of any product, in HARMAN known as the SP stage, we involve many fantastic photographers and printers from around the world, not only professionals, who kindly test the products that they are provided with and give us exhaustive feedback, both good and bad, in relation to the product used within the application that they specialise in. This way we have experience of the product in the real world and not just under controlled conditions.

    Our maxim is :

    NEVER ever presume what your customer wants, ask first, evaluate, make it, test it, and then finally CHECK back with your customer...if the circle has truly been completed LAUNCH, if not... start again...

    Hope that helps...

    Simon. ILFORD Photo / HARMAN technology Limited
     
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  15. michael_r

    michael_r Subscriber

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    Thanks so much for writing, Simon.

    First - I totally agree there is not necessarily a "correct" or "incorrect" when it comes to guides, instructions etc. There are too many variables.

    So at Ilford, the Tech Service department goes to work on all the darkroom, hands-on testing after the R&D phase. And based on your description, there is indeed a LOT of testing work. This is what I was getting at in my initial post. When you stop and think about it, it is really a huge amount of work given all the variables involved. And that's not to mention all the testing that goes on during the initial R&D phase. Hopefully one day I'll get to visit some of your facilities. It is fascinating to me.

    Thanks again for all the support you give to us on APUG.

    Michael
     
  16. VaryaV

    VaryaV Member

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    Fascinating, Simon!
     
  17. Simon R Galley

    Simon R Galley Subscriber

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    Dear Michael R,

    You are spot on... its all the variables.... and do we get it 100% correct each time, no we don't...

    I suppose its about time we did another APUG factory tour? I will ask the board of directors.

    Simon. ILFORD Photo / HARMAN technology Limited :
     
  18. Photo Engineer

    Photo Engineer Subscriber

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    Dick Henn, when in the lab, may have had from 1 - 3 technicians working for him. When I knew him, he had about 20 graduate scientists (chemists, engineers etc..) working for him and each of them had up to 3 technicians.

    Lab experiments were designed, coated, tested and evaluated - often in experimental processes so that early on C22 might have been used for color film and then they changed to C41 when the coatings were hard enough and the development and bleach cycles were ironed out. We worked on a test, deign, coat cycle of about two weeks total for all 3. Each coating set would contain a reference and up to 11 experiments. We got single layers of each experiment as well. Along with that were raw B&W coatouts of each emulsion. The emulsion makers ran loads of tests before we got them and I could give a long description of that as well!

    Anyhow, once something looked good at 4.5" width, we went to 11" or 4.5" at high speed on the large KRL coater called J9. It sat on the top of B-59. Then we coated film on 21 machine (21" wide). If the coating looks good at 21" width, it is then scaled up to production.

    At that point, all films (color and B&W) are run through a standard seasoned process. For B&W, the standard is (or was) D-76. All tests were run using a 1B Sensitometer set for Daylight or Tungsten illumination (depending on product). All films were tested for spectral sensitivity using a Spectro Sensitometer, and for sharpness and grain using special instruments. All products were tested for raw stock keeping, reciprocity and latent image keeping, and the images were tested for image stability using high intensity illumination, high teperature, high humidity, pollutant gases and combinations thereof.

    (BTW, sharpness, grain and some other contrast dependent (and image polarity dependent) characteristics cannot be easily compared between film types. For example, it is difficult to compare a reversal and negative color image due to polarity and contrast.)

    Again, for every batch of film, all chemicals and emulsions were pretested for suitability before the coating was even made and so each ingredient and each emulsion would go through dozens if not hundreds of pre-approval tests before being used in a product.

    Does this help?

    PE
     
  19. Chris Livsey

    Chris Livsey Member

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  20. Oren Grad

    Oren Grad Subscriber

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    Michael's specific question was who generates the data to populate the time/temp/developer charts that are provided in each film's data sheet, and how do they do it. How did that work at Kodak?
     
  21. Photo Engineer

    Photo Engineer Subscriber

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    Oren;

    My post covered all phases, but my 4th paragraph summarized what Simon posted. The product is tested in the "Film Testing Division" and also in the "Photographic Technology Division" both of which are much reduced in size and probably renamed by now. The PTD building went down about 5 years ago and it became part of KRL from which it sprang about 40 years ago or so. The FTD tested just films, but PTD tested the entire system including taking photos, processing and printing.

    The standards were set using the guidelines sketched out in Mees and Mees and James for the best curve, and these conditions and test results are sent on to Marketing for publication as needed.

    PE
     
  22. michael_r

    michael_r Subscriber

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    Very interesting stuff, PE. Thanks for the input on this thread. So in say the FTD, there were people manually developing film over and over again at different temps, with different chemistry, for different gradients, etc etc? If we take one film testing example, say determining the recommended development time for 35mm Plux-X in a small tank at 68F for a given desired gradient, how many times would a specific test be repeated to generate data?
     
  23. Photo Engineer

    Photo Engineer Subscriber

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    Well, Michael, substitute PTD for FTD in your post. FTD did routine standard tests - more or less release testing. PTD did the stress testing of the system and did the variations. They would test film in all developers at all combinations of time and temperature and in all equipment available. Totally different work in the two divisions.

    One test was not enough, they were run multiple times and run through a statistical program to get variations and etc.. so we knew what to expect from both standard deviation of product and from errors by the customer.

    PTD was by far the larger division when compared to the FTD.

    At one time, the color processing labs were attached to the PTD. This was, I think, for quality assurance.

    PE
     
  24. michael_r

    michael_r Subscriber

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    Wow, imagine the amount of processing going on. Over and over again, changing one variable at a time. Very interesting. This is exactly the kind of thing I think about when I do my film/developer tests. Trying to be thorough and get repeatable results takes a hell of a lot of time. Although at least the EK test force had well controlled facilities to make things much more efficient. I'm thinking for example about how much time I spend just getting the temperatures right and then trying to maintain them. Clearly in a Kodak research facility it would be easier to do high volume testing under controlled conditions.
     
  25. Photo Engineer

    Photo Engineer Subscriber

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    Our sinks were larger than the common bathtub in some cases. They were double jacketed and insulated. They were powered by steam (yes steam and were they noisy when heating up) and by chilled water.

    We had DW, DI and tap water piped to every darkroom along with nitrogen. We had a stockroom with literally thousands of chemicals and almost any type of equipment you can imagine.

    PE
     
  26. Stephen Benskin

    Stephen Benskin Member

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    From Dry Plates to Ektachrome Film by C.E. Kenneth Mees
    also, C.E. Kenneth Mees, Pioneer of Industrial Research by T.H. James