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  1. #21

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    Hi,
    Here are some scans of reversal film I shot last weekend. I'd like to have been able to say that they are straight scans with no manipulation, but for reasons I don't know the scans didn't do justice to the contrast of the slides and so I have regrettably had to tweak them to give as close an accurate representation as I can. Even that is difficult, as these new-fangled LCD screens give different brightness/contrast levels depending on the angle of viewing. Anyway, for better or worse, here they are. The basic process is FP4 @ 125ASA, first dev Ilford PQ Universal + Hypo, stop and wash, permanganate bleach, second dev PQ Universal, no Hypo. It's a combination of Ilford's process (with far less Hypo than they suggest) and the permanganate/bisulphate bleach recommended by Existing Light. If anyone's interested, I can post the exact process.
    Steve

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    Last edited by Steve Roberts; 05-23-2013 at 05:41 AM. Click to view previous post history.

  2. #22

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    Quote Originally Posted by Rudeofus View Post
    Since you already use a clearing bath after bleaching, I would say that MnO2 is the least likely source of your problems, and I would only look into that once you have excluded all other options. If you are not sure about your clearing bath, there is a thread here on APUG where a "rinse with dilute sodium metabisulfite (a 3% solution does the trick)" is suggested. Key seems to be Sulfite ion in acidic environment.

    Neither Ag2S, nor tiny Silver crystals will be affected by fixing, so I suggest you fix your milky test clips and check whether brown stain is visible and then check for Ag2S vs. tiny Silver Crystals. Tiny Silver crystals can be bleached away with C41/E6 bleach, while Silver Sulfide will be unaffected.
    Rudeofus. Thank-you for the very clear answer and methodological approach to investigating the problem. That's just what I needed!

  3. #23

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    Quote Originally Posted by Steve Roberts View Post
    Hi,
    Here are some scans of reversal film I shot last weekend. I'd like to have been able to say that they are straight scans with no manipulation, but for reasons I don't know the scans didn't do justice to the contrast of the slides and so I have regrettably had to tweak them to give as close an accurate representation as I can. Even that is difficult, as these new-fangled LCD screens give different brightness/contrast levels depending on the angle of viewing. Anyway, for better or worse, here they are. The basic process is FP4 @ 125ASA, first dev Ilford PQ Universal + Hypo, stop and wash, permanganate bleach, second dev PQ Universal, no Hypo. It's a combination of Ilford's process (with far less Hypo than they suggest) and the permanganate/bisulphate bleach recommended by Existing Light. If anyone's interested, I can post the exact process.
    Steve

    Click image for larger version. 

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    They look like very good indeed!

  4. #24

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    Quote Originally Posted by Steve Roberts View Post
    Hi,
    Here are some scans of reversal film I shot last weekend. I'd like to have been able to say that they are straight scans with no manipulation, but for reasons I don't know the scans didn't do justice to the contrast of the slides and so I have regrettably had to tweak them to give as close an accurate representation as I can. Even that is difficult, as these new-fangled LCD screens give different brightness/contrast levels depending on the angle of viewing. Anyway, for better or worse, here they are. The basic process is FP4 @ 125ASA, first dev Ilford PQ Universal + Hypo, stop and wash, permanganate bleach, second dev PQ Universal, no Hypo. It's a combination of Ilford's process (with far less Hypo than they suggest) and the permanganate/bisulphate bleach recommended by Existing Light. If anyone's interested, I can post the exact process.
    Steve

    Click image for larger version. 

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    Steve. They look very good. I think it would be very helpful to anyone doing or considering reversal processing if we could see your exact process. It is always useful to be able to compare details and you have achieved a good tonal balance with your particular process and at full EI.

  5. #25

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    I'll type up my process into a legible form and post it here, probably after the weekend as I don't have much in the way of email at home.
    Best wishes,
    Steve

  6. #26

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    Hi,
    As promised, here are the details of the process I've reached so far. I say "so far" because all things are subject to tweaking! To measure the chemicals by weight I use a small digital balance that reads to 0.01g (how accurate it is, I don't know, but if the first d.p. is accurate, that's probably good enough as long as it's consistent. I bought the balance from a jewellery shop for £20. As has been said, local issues such as water characteristics and individual ways of working will have an effect on the end results, but for what it's worth, here goes:

    Black and White Reversal Process for Ilford FP4 exposed at 125ASA.
    Check List.
    Ilford PQ Universal developer
    Stop bath
    Fixer
    Thermometer
    Gallon of water at 20 degs C
    Potassium Permanganate 0.8g
    Sodium Bisulphate 11g
    Sodium Metabisulphite 12.5g
    Hypo stock solution 20g in 200cc water (equates to 10cc per gram hypo required)
    Lamp with 100W bulb

    All at 20 degs C until final wash.

    1) Pre-soak for 5 mins.

    2) Develop Ilford PQ Universal 1 + 5 + 4g/l hypo.
    Invert twice each 15 secs for 10 mins.

    3) Stop bath 1 min (not in Ilford procedure – see note below)

    4) Water wash (Ilford recommended procedure)
    Invert 5 times, discard.
    Invert 10 times, discard.
    Invert 20 times, discard.
    Invert 20 times, leave film soaking whilst making up bleach, then discard.

    5) Bleach – 11g Sodium Bisulphate dissolved in 400cc water, then add 0.8g Potassium Permanganate – 5 minutes continuous agitation.

    6) Water wash (Ilford recommended procedure)
    Invert 5 times, discard.
    Invert 10 times, discard.
    Invert 20 times, discard.
    Invert 20 times, leave film soaking whilst making up clearing bath, then discard.

    7) Clearing Bath – 12.5g Sodium Metabisulphite dissolved in 400cc water
    Invert twice each 15 secs for 2 mins.

    8) Water wash (Ilford recommended procedure)
    Invert 5 times, discard.
    Invert 10 times, discard.
    Invert 20 times, discard.
    Invert 20 times, discard.
    9) Second exposure – underwater in translucent plastic jug, 12” from 100W incandescent lamp, moving constantly and evenly. (Ilford say remove from reel, but I leave film in my translucent white plastic Paterson reel with no problems).

    10) Second developer – Ilford PQ Universal 1 + 9, 6mins

    11) Stop 1 min

    12) Fix

    13) Rinse @ 20 degs C then reduce rinse in stages of about 3 degrees to tap water temperature. Wash 20 mins.

    14) Dry.

    Notes.

    a) Hypo is supplied in large crystals, so a larger quantity in a stock solution seemed more accurate. Ilford recommend 12g/litre, which I found excessive, leading to blown light areas and lack of blacks.

    b) Ilford recommend that the “time and temperature be closely monitored if consistent results are to be obtained”. Given that, why do they not suggest a stop bath to arrest development? Their application sheet (2003) says that the acid bleach “stops development immediately” ... hmmmm .... only after the 5 mins wash process, though!

    c) Bleach – dissolve Sodium Bisulphate first at it doesn’t dissolve readily and once the permanganate has been added you won’t be able to see whether the bisulphate is all in solution. Ilford procedure uses sulphuric acid but this is Existing Light’s recipe. Though some say this softens the emulsion unduly, I haven’t found it to be a problem as I leave film in the reel for 2nd exposure.

    d) From completion of bleaching, the process can theoretically be continued with the top of the tank removed though I don’t do this as I prefer to regulate the second exposure later on. Don’t ask me why – I just do!

    e) I prefer to make up the bleach and clearing solutions when I get to that part of the process, largely because I don’t have much space. I check and correct the temperature of these as necessary, though I suspect I’m being over-cautious.

    f) The translucent white plastic reel allows sufficient transmission/reflection of light, but I suspect that a black Bakelite reel would give rise to unexposed areas.

    g) Time – allow about two hours for the whole process, as there are many stages and weights/volumes to measure. However, apart from the first development stage, the rest of the process can be completed in easy time, stopping to make a cup of tea, take a breather from all the inversion agitation, etc. during one of the many washing procedures, as required!

    Good luck and I hope to hear how others get on with the process.

    Steve

  7. #27

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    Hi Steve,
    your process is almost spot on with mine (SilverInversion). It would be interesting to see whether "Iron Out) (sodium dithionite based) can yield a higher DMax if used instead of the re-exposure and second development. I didn't have the time to try it yet.

  8. #28

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    Thanks for the piece of advice but chromium compounds are out of my league...

  9. #29

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    Quote Originally Posted by Steve Roberts View Post
    Hi,
    As promised, here are the details of the process ...

    Hypo stock solution 20g in 200cc water (equates to 10cc per gram hypo required)


    Steve
    Steve,

    thanks very much for taking the time to describe your process.

    The only thing I'm not clear on is what you are using for hypo (and whether it's anhydrous or not). I understand that hypo is usually Sodium thiosulfate or Ammonium thiosulfate. I use Sodium thiosulfate but my quantity (with Dokumol) is a fraction of what you use. I think the quantity of hypo (or other silver solvent) is the prime factor influencing the image, given any active-enough developer. Developer time doesn't seem to make too much difference (at least with the Dokumol). e.g. 12 mins or 15 mins give very similar results.

    I wonder whether those last 20 inversions at rinse stage are necessary?

    Out of interest, how long did it take you to get to this stage in your process?
    Last edited by mr.datsun; 05-29-2013 at 11:29 AM. Click to view previous post history.

  10. #30

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    Quote Originally Posted by johnielvis View Post
    just out of curiousity--has the brown stain boogeyman been identified yet or is it still a plague?

    I had a brown stain problem, but it was cured by a change in diet.
    I've had to put film processing on the back-burner for a while. I will need to try the C41 E6 bleach test but no idea how I can get a small enough amount for a test.

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