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Thread: Kodak Techpan

  1. #11

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    Another developer you can try with Tech Pan is C-41. It works quite well.

    - Mike

  2. #12
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    Yes, I've seen that mentioned several times. What time/dilution/speed etc?
    "He took to writing poetry and visiting the elves: and though many shook their heads and touched their foreheads and said 'Poor old Baggins!' and though few believed any of his tales, he remained very happy till the end of his days, and those were extraordinarily long "- JRR Tolkien, ' The Hobbit '.

  3. #13
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    Sorry for the delay but I had to dig through 15-16 years worth of notes. It's been that long since I seriously used Tech Pan.

    Ok rated at an EI of 25 I developed for 9 1/2 minutes in C41 developer at a temperature of 70C. I used the developer from the Beseler Color Kit as well as begging a liter once in a while from my local pro-lab.

    Rinsed the film and fixed using regular fixer. I would suggest you shoot a few test rolls first. I am looking at some 120 negatives I took in Greece, normal contrast with good shadow detail.

    Hope this helps

    - Mike

  5. #15

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    After a long hiatus, I have begun using Tech Pan again (a friend gave me an out-of-date 50 sheet box of 4X5). I used Tech Pan extensively in the late 1970's and early 1980's, developing it in POTA and a buffered POTA variant of my own devising. My results were excellent but EI's were very low.

    I have been using Pyrocat-HD with Delta 100, Pan F+, Acros 100 and TMax 100 with outstanding results. I have also been testing a variant (suggested by Patrick Gainer) with these films that replaces the catechol 1:1 with Hydroquinone and eliminates the bisulfite and bromide (results - so far -are fully equivalent with Pyrocat-HD). I have been testing Tech Pan in this Pyrocat-HD variant developer and the results have been excellent.

    Solution A:
    Phenidone: 0.2 grams
    Hydroquinone: 5 grams

    Dissolve these chemicals in a small amount of methanol, then add Ethylene Glycol to 100 ml and mix (I do these steps under a ventilated lab hood wearing Nitrile gloves). The Ethylene Glycol acts as the preservative, so the bisulfite is not needed. I am not having film fog problems, so I eliminated the bromide, as well.

    Solution B:
    Potassium Carbonate: 100 grams

    Dissolve the carbonate in 70 ml of boiled deionized or distilled water. The resulting volume of solution will be 125 - 135 ml.

    As a starting point, try an EI of 64 and develop in 10 ml of A plus 10 ml of B plus 1000 ml boiled deionized or distilled water (the resulting one-shot solution will be a yellow-amber color). This is the 1:1:100 dilution. In a small tank or tray, develop Tech Pan for 12 minutes at 21 deg C with no agitation. Rinse with water and Fix in a non-hardening Fixer (I use TF-4).
    The resulting D-Log E curve is similar to the ones produced by Tech Pan developed in POTA and Technidol.

    If you look at the Photographer's Formulary Modified Windisch Developer, the working solution concentration of catechol is .3125 grams/liter. This suggests that a 6:6:1000 dilution of Pyrocat-Hd or the Hydroquinone variant would also work and my initial tests with this dilution confirm this. A suggested starting point is an EI of 64 for Tech Pan developed for 16 minutes with no agitation at 21 deg. C.
    Tom Hoskinson
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  6. #16

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    Tom,
    Thank you for posting the results of your testing.

    I wonder about your statements of equivalency to Pyrocat. Have you done any densitometric testing and if so how do you account for the fact that your formulation does not provide any proportional stain?

    Thanks again.

    Donald Miller

  7. #17

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    Donald,
    I have perfomed densitometric testing on both formulations and have microscopically (optical) inspected the negatives - film from the same emulsion numbers, exposed the same and developed in both developers.

    The Hydroquinone version of Pyrocat-HD does provide proportional staining and tanning (as it should with no or low sulfite). The stain image is a slightly different color (from the Pyrocatechol version) but otherwise is very similar.

    To quote Patrick Gainer: "Hydroquinone is 1,4-dihydroxybenzene. Pyrocatechol is 1,2-dihydroxybenzene. According to theory, any developer with two or more active hydroxyl groups will be an active tanning and staining developer."

    Gainer cites "The Theory of the Photographic Process": Chapter 13: "The Developing Agents and Their Reactions" by W.H. Lee.

    See "The Role of Antifreeze in Photographic Science" by Patrick A. Gainer in Volume 25, No. 2 of Photo Techniques, March/April 2004.
    Tom Hoskinson
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  8. #18

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    Tom,

    Thank you for that explanation. What were your measurements of the proportional stain density of the Hydroquinone based developer that you formulated when read through the blue channel and if you have it, the UV stain density as well when compared to the visual density?

    Also the comparative values of the Pyrocat developer with the same readings.

    This may be of interest to those who have an aversion to catechol or pyrogallol based developers.

    Thanks again,

    Donald Miller

  9. #19

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    Donald,

    Good suggestion.

    I only have the visual density readings now, but will get back on the densitometer next week, get the other data and post it.
    Tom Hoskinson
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  10. #20

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    Donald, it took longer than I expected. I ended up using a 12% Stock Solution of NaOH in Deionized Water as the alkali and two 1% Stock Solutions: Catechol and Hydroquinone in Ethylene Glycol - no sulfite or bromide - as the developers. Here are some results for 120 roll Kodak Tech Pan. The working developer is 3 parts Q or C stock soln plus 1 part NaOH stock soln plus 100 parts deionized water. Stand development in a tank was for 20 min. at 70 deg. F. Here are the densities for Hydroquinone:

    Visual Blue Channel
    .03 .03
    .12 .16
    .33 .41
    .48 .62
    .60 .74

    The results for the Catechol developer are similar.

    Visual Blue Channel
    .12 .15
    .35 .42
    .48 .55
    .60 .67
    .71 .79
    Tom Hoskinson
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