Permanganate-based b&w reversal simply isn't quality reversal

Discussion in 'B&W: Film, Paper, Chemistry' started by Alessandro Serrao, Aug 9, 2005.

  1. Alessandro Serrao

    Alessandro Serrao Member

    Messages:
    997
    Joined:
    Oct 20, 2004
    Location:
    Rome, Italy
    Shooter:
    35mm
    It's more a statement than a question: after two full days of experimentation, I come to the conclusion that using a permanganate-based bleach for b&w reversal simply doesn't give a high quality slide, for what are my quality standards.

    Am I too picky, am I not?

    Comments are welcome. I will revert back to b&w negatives. Thanks for all the helpful replies on my last post, which was related to my b&w reversal experimentation.
     
  2. Dug

    Dug Member

    Messages:
    123
    Joined:
    Feb 29, 2004
    Location:
    Seattle WA U
    Shooter:
    Multi Format
    Alessandro - are you using a kit or mixing it from scratch? What was the quality issue you ran into? I was considering it for internegative work, but have not done any experimentation. The kind of vague instructions about exposing to light as part of the process makes me wonder if there are just too many variables to get a consistant result. Is their anyone who has had sucess?
     
  3. Alessandro Serrao

    Alessandro Serrao Member

    Messages:
    997
    Joined:
    Oct 20, 2004
    Location:
    Rome, Italy
    Shooter:
    35mm
    Basically the quality issue I'm running through is that there's a good probability that the emulsion can come off the film base due to the high pH changes involved in the process.
    Or the emulsion can remain irrimediably reticulated, the light exposure add another variable to the process ecc...
    Black and white negatives are not intended to be reversed, there are other type of films intended for the use.

    Let's use what is made for: Scala, Foma 100R.
    I'm tired to ruin rolls after rolls just because the process has too many variables to count.
    Forget the consistant results: have a Scala roll processed by a Scala authorized lab, that would be the best bet.

    As I said I'll revert back to the ol' b&w negatives, to what's is intended for.
     
  4. nze

    nze Member

    Messages:
    705
    Joined:
    Apr 12, 2004
    Location:
    France
    Shooter:
    Multi Format
    Allesendro
    you may check http://www.galerie-photo.com/inversion-film-noir-blanc.html . for sure the article is in french but you will see that Claude get low B+fog. He use to add sulfocyanure in the first developper and to rinse between each step.

    Personally I use the dichromate method beacause of I got a lot of bichromate at home , but I already try the permangante and the ceriu mehod and all three give good result.

    Regards
     
  5. Alessandro Serrao

    Alessandro Serrao Member

    Messages:
    997
    Joined:
    Oct 20, 2004
    Location:
    Rome, Italy
    Shooter:
    35mm
    What exactly do you mean by good results?
    I've got too much emusion softening so that the image is not good.
    Maybe I can give it a try once again.
     
  6. nze

    nze Member

    Messages:
    705
    Joined:
    Apr 12, 2004
    Location:
    France
    Shooter:
    Multi Format
    By good result I mean that I do platinuum and carbon printing with the negative I get from; But you want direct positive and in is about the same.
    Some fim need to be harden after the bleaching , if not you will get problem with them. I usggest you to use a developper with sulfocyanure in it, rinse, bleach, rinse , harden and then expose to light and redevelop. If you ned help with the french article I may translate it. It ggive good information about the film to use. For example Efke film seems to give better result with the lower B+fog but need to be harden to avoid any trouble.

    SO I change My words and write that you can get stunning result with this method.
     
  7. Gerald Koch

    Gerald Koch Member

    Messages:
    1,670
    Joined:
    Dec 14, 2004
    Shooter:
    Multi Format
    Curious as Ilford recommends a permanganate bleach for reversal of their B&W films.

    I have always used a dichromate bleach for both B&W and color films and found it to be very dependable. There may be some pressure to use permanganate rather than dichromate since the later is more dangerous.
     
  8. Alessandro Serrao

    Alessandro Serrao Member

    Messages:
    997
    Joined:
    Oct 20, 2004
    Location:
    Rome, Italy
    Shooter:
    35mm
    What kind of hardener do you suggest me to use?
    I have only the potassium alum based hardener.
    Can it be used alone (ie not in a fixer)?
    I haven't neither the sulfocyanure buy only hypo: is that the same?
     
  9. Jordan

    Jordan Member

    Messages:
    590
    Joined:
    Sep 21, 2004
    Location:
    Toronto, Can
    Shooter:
    Multi Format
    Alessandro, you posted this on photo.net and USENET as well, but nowhere do we see what process you are using. What is your first dev made of? How are you formulating your bleach? What are your temperatures and times? B&W reversal has a lot of variables, if you are trying to "invent" a new process you need to be very patient.
     
  10. Alessandro Serrao

    Alessandro Serrao Member

    Messages:
    997
    Joined:
    Oct 20, 2004
    Location:
    Rome, Italy
    Shooter:
    35mm
    Yes, I posted it on USENET and photo.net. On USENET there's my complete recipe ("B&w proper reversal formula") but for convenience's sake I will repost it here:

    I'm getting into developing my own b&w reversal film (now it's only
    T-Max 100).

    I've tried to set up a complete formula from various sources on the net and I've came up with something like this:

    1) Kodak D-19 with sodium thiosufate added at 16g/l for 8 minutes, standard Kodak agitation

    2) Pre-bleach bath: Tetenal hardener alone @ 25ml/l for 5 minutes

    3) Wash

    4) Bleach: potassium permanganate 4g/l (part A) and sodium bisulfate
    34g/l (partB). Mix 1:1 just before use, for 2 mintes

    5) Wash

    6) Clearing: potassium metabisulfite 30g/l, for 2 minutes

    7) Wash

    8) Pre-exposure: Photo-flo for 30 seconds

    9) Wash

    10) Re-exposure: by means of a tungsten lamp 150w from a distance about 1mt for 2+2 minutes (2+2 refers to both faces of reel)

    11) Second development: Kodak D-19 for 6 minutes

    12) Wash

    13) Fix: a fixer bath consisting of 120g sodium thiosulfate, 10g
    sodium sulfite, 30g sodium metabisultite. To this I've added the Tetenal
    hardener @ 25ml/l: the solution gets cloudy but fixes nevertheless...

    14) Wash

    15) Wetting agent

    16) Hang to dry


    Every step is carefully mantained to 20°C +-1°C by means of water baths

    I got the following results:
    - on T-Max 100 exposed at 100 I get very dark slides (dunno if they are underexposed or underdeveloped)
    - the emulsion side of the film gets non uniform: it gets as something
    has softened it too much.

    What I'm doing wrong?

    Precedently with Ilford films I got the emulsion off the base in my
    hands!!!
     
  11. Jordan

    Jordan Member

    Messages:
    590
    Joined:
    Sep 21, 2004
    Location:
    Toronto, Can
    Shooter:
    Multi Format
    Alessandro --

    My comments, as before, are as follows:

    (1) I think you are underexposing your film. I seem to recall that Kodak, in their T-MAX reversal process, recommends that the film be exposed at EI 50.

    (2) Your bleach recipe seems under-acidifed relative to what I use. Have a look here:
    http://www.angelfire.com/wi/spqrspqr/photo/bwreversal.html
    There they recommend around 55 g/litre of sodium bisulfate for the "B" part of the bleach. I'm not sure if this will make a big difference in your bleaching times.

    (3) If this step fails, I'm not sure what to suggest. Is the Tetenal hardener meant to be used alone, or added to fixer? I ask because its action may be pH-dependent.

    (4) If all of these fail, maybe you need to try dichromate bleach and see if that fixes the problem.
     
  12. Jordan

    Jordan Member

    Messages:
    590
    Joined:
    Sep 21, 2004
    Location:
    Toronto, Can
    Shooter:
    Multi Format
    Actually, in reading through the reversal recipe on the Photographer's Formulary web site (here: http://www.photoformulary.com/uploads/01-0600.DOC) they use the same reversal bleach composition as you (from the Dietrich article in Photo Techniques in the late 80s). So I'm not sure what's going on here.
     
  13. Donald Qualls

    Donald Qualls Member

    Messages:
    1,845
    Joined:
    Jan 19, 2005
    Location:
    North Caroli
    Shooter:
    Multi Format
    A couple suggestions. First, if you add an alum hardener to the fixer, the fixer must be acidic. Your fixer, made with thiosulfate, sulfite, and metabisulfite, is probably very slightly alkaline. Add some acetic acid to the fixer and you'll stop the clouding, though it's probably better to abandon hardener in the fixer in favor of correcting the pre-bleach hardening bath. The hardener alone in the the pre-bleach bath is probably doing nothing if the solution isn't acid; use stop bath strength acetic acid in place of plain water if the hardener concentrate itself isn't notably acidic. Correcting the pre-bleach hardener to be acidic, so the alum can actually harden the emulsion, will likely help considerably with the reticulation, though it may also require lengthening the bleach, clearing bath, second dev, and fixing, and especially washing.

    What you describe as dark slides may mean you need more silver solvent in your first developer (fog) or that you need to develop longer in the existing first dev (underdeveloped). Underexposed isn't very likely; most B&W negative films gain speed in a correctly working reversal process (many years ago, Panatomic X had to be exposed at EI 64-80 for reversal, where 25-32 was normal for negatives).
     
  14. Alessandro Serrao

    Alessandro Serrao Member

    Messages:
    997
    Joined:
    Oct 20, 2004
    Location:
    Rome, Italy
    Shooter:
    35mm
    A new try in a few days...


    1) Probably you're right: I'm underexposing the film in relation to how much hypo I'm using in the first dev;

    2) I took that recipe from the Photographer's Formulary T-Max reversal processing kit, which calls explicitily for 34.5g of sodium bisulfate for 1 liter.
    This kit was after the March/April Darkroom Techniques issue of Mr. Dietrich;

    3) The Tetenal hardener is meant to be used in a fixer. I think much better results comes from using Formalin as per Kodak SH-1 recipe, present in Kodak Pub. J-1; but since I haven't formalin I can't do the pre-hardener bath before the bleach so I'll try again with a simple hardening fixer as last resort; In September, when I'll have access to my local chemistry shop, I'll do some other tests with formalin; I think this is the MOST IMPORTANT step to insure a full quality reversed slide;

    4) Never in my life I'll touch dichromate (it's too dangerous and isn't worth the candle - not that formalin is less dangerous though... :mad: )
     
  15. nze

    nze Member

    Messages:
    705
    Joined:
    Apr 12, 2004
    Location:
    France
    Shooter:
    Multi Format
    I use a formol bath to harden the film. but alun should work too.

    to get good slide it is better to overexpose your film for a about 2 stops.

    I add sodium sulfocyanure to the first developper, it hep to keep fog low with the following step of the inversion

    May you try this , first exposse the T max @25 iso
    Then you may develop first with PQ ilford 1+9 +9.5gm sodium sufocyanure added by each liter. Dev time 8.5 min@20°C.

    Then harden your film iin
    Formol 37% 15ml
    sodium carbonate 5g
    Water to make 1l

    for 2 minutes
    then follow all the other step till the lasst deelopment then instead of D19 you may use PQ @1+4 with no sulfosyanure added.

    regards
     
  16. Alessandro Serrao

    Alessandro Serrao Member

    Messages:
    997
    Joined:
    Oct 20, 2004
    Location:
    Rome, Italy
    Shooter:
    35mm
    Who is right?



    The Tetenal hardener already has acetic acid into it.



    I've used the Tetenal hardener alone and since it contains acetic acid I've used the hardener as a stand-alone stop bath between the first developer and the bleach (with a copious water bath after the hardener) but the reticulation still exists.

    On the Tetenal hardener bottle there's explicitily written: Hardener for fixer bath, so I'm assuming that the hardener coundn't used alone.

    With what I'm left?


    Donald: have you conducted your own tests? I really want to know how you do the reversal process, maybe there's something I forget to do.
     
  17. Jordan

    Jordan Member

    Messages:
    590
    Joined:
    Sep 21, 2004
    Location:
    Toronto, Can
    Shooter:
    Multi Format
    Alessandro, the basics of your process are correct, and the use of Kodak D-19 as the basis for a reversal first developer is well-documented in the photography literature. The "sodium sulfocyanure" that NZE refers to is known in English as sodium thiocyanate, it is an alternative silver halide solvent that you can use if you want to. The effect is the same, but sodium thiocyanate works at lower concentrations, but is more expensive and harder to use. Thiosulfate is fine, but you should mix it into the developer right before use (don't let it stand).

    The response of films to the reversal process differs. Panatomic X might get a speed boost, but Kodak clearly states in their literature for the TMAX Reversal Kit (see here: http://www.kodak.com/global/en/professional/support/techPubs/j87/j87.jhtml) that TMX needs a one-stop overexposure for "normal" results in the reversal process.

    As far as the hardening is concerned, I'm not sure what to recommend. I think some small E-6 kits contain formalin stabilizers as the last bath. Maybe you could use one of those?
     
  18. Donald Qualls

    Donald Qualls Member

    Messages:
    1,845
    Joined:
    Jan 19, 2005
    Location:
    North Caroli
    Shooter:
    Multi Format
    Not being familiar with the Tetenal hardener, I wasn't sure if it was acidic or just a plain alum solution, perhaps buffered to prevent it becoming alkaline and precipitating an insoluble aluminum salt.

    Given that the hardener incorporates acetic acid, there shouldn't be a problem with using it in either step where you do, but that doesn't explain the clouding of the fixer when you add the hardener -- it shouldn't do this.

    I haven't yet managed to do B&W reversal myself -- I've been prioritizing getting my printing setup in line, and am just about there; should be able to print this weekend. Beyond that, then, I'll need to obtain some bleach (probably copper sulfate, since it's easy to get and cheap, along with battery acid), and start working out the right ratio of fixer concentrate, additional alkali, and HC-110 or Dektol for first dev (I use HC-110 for everything but prints). I'll most likely work in sheet film, at least until I have the process completely under control, because shooting one sheet and developing is a lot faster and easier (and cheaper) than burning a whole roll of 35 mm or 120.

    My main aim with B&W reversal, however, is to shoot in-camera direct paper positives for a "one of a kind" image, similar to Polaroid but larger and cheaper. This will almost certainly work out with different needs and values than images intended for projection.
     
  19. Gerald Koch

    Gerald Koch Member

    Messages:
    1,670
    Joined:
    Dec 14, 2004
    Shooter:
    Multi Format
    Alessandro,

    What are the instructions for the Tetenal Hardener? Are you using it correctly? If they say to add it to a plain hypo solution then you are not following the directions. What you are starting with is a non hardening FIXER which alread contains, besides thiosulfate, sodium sulfite and sodium metabisulfite. For example, if you would look up the formula for Kodak F-5a Hardener you would see that it says to add the hardener to a 30% solution of sodium thiosulfate. No mention of added metabisulfite or sulfite. This is why I say that your resulting solution is too acidic causing the sulfurization.

    Film intended for reversal is usually shot at an EI above the manufacturer's rated speed. If you fail to do this the slides will be very dark.

    If you can obtain some chrome alum (potassium chromium sulfate) it is a much better hardener than ordinary alum. Use a 3% solution for 3 to 5 minutes as a hardening stopbath. This should harden the film enough that a hardening fixer is not required.

    As far as using potassium dichromate this is safe to use, as are all commonly used photochemicals, if some care is observed. I certainly consider it safer than pyrogallol and catchol which are in common use as developing agents.

    Jerry
     
  20. Alessandro Serrao

    Alessandro Serrao Member

    Messages:
    997
    Joined:
    Oct 20, 2004
    Location:
    Rome, Italy
    Shooter:
    35mm
    For what I've understood, low pH causes the precipitation of the colloidal sulfur. I'm guessing this was the case.
     
  21. Alessandro Serrao

    Alessandro Serrao Member

    Messages:
    997
    Joined:
    Oct 20, 2004
    Location:
    Rome, Italy
    Shooter:
    35mm
    The label on the Tetenal hardener bottle says: "Harder for fixing bath, diluite 25ml/l of fixer" and that's all.
    It doesn't refer to what type of fixer should be.


    Yes but it would be the same: the sulfite is contained in the hardener this time.

    Dunno wheter the same amount of sulfite is contained in the Tetenal hardener, I have to look at the Tetenal MSDS, but unfortunately it seems I can't find them.


    Isn't just the opposite? If I expose the T-Max 100 1 stop lower (@50) I'll get brighter slides. The opposite if I rate the film @100 or 1 stop higher. Isn't that way?


    I agree on the catechol, not on the pyro. The pyro is way less toxic than dichromate (as you can see from any MSDS).

    Thanks for the useful infos.
     
  22. Gerald Koch

    Gerald Koch Member

    Messages:
    1,670
    Joined:
    Dec 14, 2004
    Shooter:
    Multi Format
    You're right. Since I never do B&W I always get this backwards.
     
  23. Alessandro Serrao

    Alessandro Serrao Member

    Messages:
    997
    Joined:
    Oct 20, 2004
    Location:
    Rome, Italy
    Shooter:
    35mm
    :confused:
     
  24. Donald Qualls

    Donald Qualls Member

    Messages:
    1,845
    Joined:
    Jan 19, 2005
    Location:
    North Caroli
    Shooter:
    Multi Format
    Sulfuring of fixer, I've read, is caused by oxidation, not by low pH. High (alkaline) pH, OTOH, can/will cause precipitation of an alum based hardener. And that's the number one thing -- alum hardeners can *only* be used in an acidic fixer, not in neutral or alkaline fixers. The presence of acetic acid in the hardener may be insufficient to prevent precipitation when diluted out in either water or the near-neutral fixer formula you gave earlier. Try adding acetic acid, to at least half the strenth of acid stop bath working solution, and see if that stops the precipitation.

    Or consider changing to a non-alum hardener, which you could even apply before the first dev. The bad news is, most if not all non-alum hardeners use an aldehyde (formalin is common, but glutaraldehyde is also used) and there are some significant health risks in using these in a closed darkroom. Even those that, like Kodak's C-41 stabilizer, don't include formaldehyde in the list of ingredients contain ingredients that react to produce the stuff.

    Here's a potentially simple way to test if your precipitate is alum or sulfur: intentionally produce some and filter it out (a paper coffee filter should work, if you don't have chemical filter paper available). If it's sulfur, once the precipitate is dry it'll be yellow-white, possibly with brown and red streaks or mottling caused by particle size, and will smell strongly of sulfur oxides even at room temperature; only carbon disulfide will dissolve it, a sample will burn with a faint blue flame and smell strongly of sulfur dioxide, and heating a tiny sample with candle wax will give off hydrogen sulfide (do this outdoors -- it takes frighteningly little H2S to kill you). The alum precipitate, OTOH, will likely redissolve in acetic acid in the stop bath strength range, won't ignite at all, and won't react with candle wax in a way that gives a strong odor.

    Once you know which precipitate you're getting, you'll be ahead of where you are now.
     
  25. Gerald Koch

    Gerald Koch Member

    Messages:
    1,670
    Joined:
    Dec 14, 2004
    Shooter:
    Multi Format
    Sorry I meant to say B&W reversal processing. The main problem today is finding a suitable film with a colorless base.