Got questions about b&w reversal process

Discussion in 'B&W: Film, Paper, Chemistry' started by cinejerk, May 7, 2009.

  1. cinejerk

    cinejerk Member

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    This is my first experience with the b&w reversal process. I am trying to process some older 7262 plus-x reversal film. The film is too dark. I'm using mostly home brew
    chemicals, which is problematic in itself. The problem I'm am having is that
    the film is underexposed and I'm not sure what to push or pull. The first dev or second. Below is an old list posted by who I'm not sure. I'm sort of patterning
    my process after this.

    1.) First developer - D-76 1:1 - 9:30 @ 68F
    2.) Stop Bath - Acid Stop - 00:30 (not using this step)
    3.) Wash - Running water, 2 fill & dumps of tank
    4.) Bleach - Sodium dichromate bleach - 2:30
    5.) Wash - Fill and dump tank for about 5 minutes, until water is not orange.
    6.) Clear - Kodak Hypo Clear - Two minutes with inversion.
    7.) Re-Expose, 60 watt room light, 1:30.
    8.) Second developer - D-76 - 7:00 @ 68F
    9.) Stop, fix, wash as normal.
    7.) Wash - Running water, 2 fill & dumps of tank.

    Anyway maybe some kind soul can look this over and give me some
    suggestions. I'm not sure why the first developer is diluted.
    Any help will be appreciated.
    thanks
     
    Last edited by a moderator: May 7, 2009
  2. Jordan

    Jordan Member

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    The reason why your film looks too dark is because regular D-76 1:1 is not a suitable first developer for reversal processes.

    The role of the first developer in B&W reversal is to develop the "negative image" into metallic Ag, leaving the "positive image" in AgX form. With normal exposure, regular developers like D-76 leave a lot of undeveloped AgX left over, which results in overly dark positives if they're used in reversal processes (all that leftover AgX forms the silver in the final slide). You can get around this to some extent by massively overexposing the film, but even then, there is always leftover unexposed or undeveloped AgX that turns into Ag after the second development and creates a dark fog or haze in the image.

    To get around this problem, first developers for B&W reversal need to have high activity -- much higher than what is usually found in a B&W film developer. D-76 1:1 or even D-76 straight are not enough. Typically, reversal developers look more like paper developers than film developers. If you look at Ilford's PDF file on reversal processing, they actually provide a formulation for a reversal first developer that's based on Bromophen paper developer.

    In addition, first developers pretty much always contain a silver halide solvent like sodium thiosulfate or potassium thiocyanate. These ingredients essentially provide a bit of fixer-like action during developing, clearing out traces of AgX that simply can't be developed by even the most active developer. Leaving out the silver solvent typically makes the finished positives look "dark" overall -- areas that should be light (sky, white objects, etc.) have too much density.

    My suggestion would be to look at the Ilford reversal-processing PDF and use the process they recommend. You'll have far more luck with that than you will with D-76 as a first developer.
     
  3. Photo Engineer

    Photo Engineer Subscriber

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    D-19 or D-8 are often used as the first developer, with about 0.5 - 1.0 g/l KSCN or NaSCN as Jorday says.

    PE
     
  4. cinejerk

    cinejerk Member

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    Thanks Jordan and PE. I have a lot of D-76 so what can I add to it to make it more active? sodium hydroxide?
    PE I'm not a chemist so please spell out KSCN and NaSCN thanks. I know it's sodium and potassium something ;-)
     
  5. Photo Engineer

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    KSCN = Potassium Thiocyanate, NaSCN = Sodium Thiocyanate.

    Making the D76 more alkaline with NaOH (Sodium Hydroxide) will probably work, but you have to do it in a repeatable manner for the future work you may do. If you want to do something like this, you should get the materials needed rather than improvise.

    PE
     
  6. Lowell Huff

    Lowell Huff Inactive

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    We make reversal chemistry.
     
  7. cinejerk

    cinejerk Member

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    Ok here are some formulae to make 1ltr
    D19
    elon 2gm
    sodium sulfite 90gm
    hydroquinone 8gm
    sodium carb 52gm
    potassium bromide 5gm

    D8
    sodium sulfite 90gm
    hydroquinone 45gm?
    sodium hydroxide 37.5gm
    potassium bromide 30gm

    What makes them more suitable?
     
  8. Photo Engineer

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    Carbonate vs Borate gives a much higher pH and buffer capacity, which gives better first development. Sodium Hydroxide also increases pH for higher contrast. I'm not sure that the HQ level in D8 is correct. I assume that is the reason for the "?". I do not have the formula handy.

    PE
     
  9. cinejerk

    cinejerk Member

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    Yea, I don't know about that amount of hydroquinone either. I'm getting these out of an old(1955)handbook of chemistry & physics.
    D76
    elon 2gm
    sodium sulfite 100gm
    hydroquinone 5gm
    borax 2gm

    Give me a ball park amount of lye to add to this.
     
  10. Ian Grant

    Ian Grant Subscriber

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    That's the correct level of Hydroquinone in D8 and Bromide :D

    D8 is a high contrast developer, D19 would be more suitable, it becomes D67 when you add Thiocyante, this is Kodak data for Reversal processing.

    Ian
     
  11. cinejerk

    cinejerk Member

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    Thanks Ian. I just have so much D-76 that I thought there should be something I could do to use it.
     
  12. Ian Grant

    Ian Grant Subscriber

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    5 gms of Sodium Hydroxide is very roughly equivalent to 50 gms Sodium Carbonate, so that could be a staring point to increase the pH and activity of D76 as Ron (PE) suggested.

    Ian
     
  13. Photo Engineer

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    It will also raise the pH but lower the buffer capacity.

    PE
     
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  15. Jordan

    Jordan Member

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    My own advice would be to not bother trying to adulterate D-76 into a reversal developer. Kodak sells D-19 powder in a yellow packet -- B&H sells it and I'd imagine it's also available elsewhere. It's much more suitable for reversal processing (once you add a bit of KSCN or sodium thiosulfate). Keep your D-76 for processing negatives!
     
  16. nworth

    nworth Subscriber

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    Just for reference, this is the developer Kodak currently lists as a reversal film first developer:

    Kodak D-94 reversal film first developer
    Water (50C) 750 ml
    Metol 600 mg
    Sodium sulfite (anh) 50 g
    Hydroquinone 20 g
    Potassium bromide 8 g
    or
    Sodium bromide 7 g
    Sodium thiocyanate (51%) 9.1 ml
    Sodium hydroxide 20 g
    WTM 1 l
    pH at 27C = 12.75
    Specific gravity at 27C = 1.074
    Develop motion picture reversal film for 2 minutes at 20C or 40 seconds at 35C.
    Variation:
    Substitute 420mg of DTOD for the sodium thiocyanate. This variation is called D-94A. Note: DTOD is HOCH2CH2-S-CH2CH2-S-CH2CH2OH (1,2-di(2-hydroxyethylthio)ethane).

    This developer was designed for machine processing, and it is probably faster than you would like for small batches. D-19 with added thiocyanate might be a better choice. The second developer is similar, but without the thiocyanate:

    Kodak D-95 reversal film second developer
    Water (50C) 750 ml
    Metol 1 g
    Sodium sulfite (anh) 50 g
    Hydroquinone 20 g
    Potassium bromide 5 g
    or
    Sodium bromide 4.5 g
    Potassium iodide 250 mg
    Sodium hydroxide 15 g
    WTM 1 l
    pH at 27C = 12.15
    Specific gravity at 27C = 1.065
    After an 800 footcandle second reexposure, develop reversal film for 50 seconds st 20C or 20 seconds at 35C

    The second development goes to completion, so timing is less critical than for the first developer. Still, too long in the second developer chances fog. This second developer is pretty vigorous, and you might want to use something slower, maybe D-19 or D-72. I suspect that D-72 (undiluted) with added thiocyanate might make a pretty good first developer. Any comments?
     
  17. Ian Grant

    Ian Grant Subscriber

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    The major problem with D94 is the extremely short development times, particularly as the First development needs to be accurate, it's designed purely for mechanical processing of cine film

    A better alternative is the Filmotec/Orwo system as this is more practical for home processing.

    Ian
     
  18. cinejerk

    cinejerk Member

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    so even if I did buy D19 I would have to adulterate it with KSCN?

    What really blows me away is why in the original posting it shows D76
    diluted?
    Why would you do this if you need a faster acting/stronger developer?
     
    Last edited by a moderator: May 7, 2009
  19. Ian Grant

    Ian Grant Subscriber

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    That converts it into D67 which is a Kodak published formula for a First Developer for Reversal processing. So hardly adulteration, rather adaption :D

    Ian
     
  20. Photo Engineer

    Photo Engineer Subscriber

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    Well, did you see results from that post? Could it be an error? IDK, but I do know that both Ian and I are giving you sound advice as far as we know how.

    PE
     
  21. Jordan

    Jordan Member

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    I'm with PE on this one. There are a lot of reversal formulas out there. (I even posted my own at one point.) Few of them are accompanied by "actual results". The ones that are published or manufactured by the major companies tend to be more reliable.
     
  22. cinejerk

    cinejerk Member

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  23. Ian Grant

    Ian Grant Subscriber

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    Don't believe everything you read :D

    It's entirely possible someone uses D76 1+1 for Reversal processing of high contrast films, but that post flies in the face of accumulated wisdom, and all published formulae.

    Ian
     
  24. nworth

    nworth Subscriber

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    D-67 is really quite different from D-76. In fact it is D-19 with the addition of 2 grams per liter of potassium thiocyanate. The thiocyanate definitely helps both to produce clear highlights and to increase the shadow density. I've seen a suggested development time of 8 minutes for PXN.

    D-72 is similar to Dektol. That or a similar paper developer could be used as a second developer.
     
  25. cinejerk

    cinejerk Member

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    The only difference I see between D19 and D76 is 3 grams of hydroquinone and some sodium carb and pot bromide. What does the potassium bromide do to make it a better first developer?
     
  26. Ian Grant

    Ian Grant Subscriber

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    The most critical addition is the carbonate compared to D76 this will make the developer significantly more vigorous and contrasty, the Hydroquinone will help as well. Bromide is left out of some Reversal first developers as you don't want too much restrainer.

    In fact Kodak used to recommend D168 which is identical to D67 (D19 + Thiocyanate) except has no Bromide.

    Ian