Removing brown tone from reversal processed b&w?

Discussion in 'B&W: Film, Paper, Chemistry' started by mr.datsun, May 16, 2013.

  1. mr.datsun

    mr.datsun Subscriber

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    Having reached an (almost) acceptable plateau in my reversal processing experiments with Dokumol/Dokumol (1st/2nd dev), I switched tests to Rodinal/Rodinal to get a fresh perspective on things.

    Rodinal has suddenly proved to be very viable alternative for me as a Reversal 1st dev. But I am now getting warmer-browner tone images than I was getting with the cooler neutral Dokumol which I really do not want.

    I first used Rodinal/Rodinal and found that a Rodinal/Dokumol combination (maybe) appears to ameliorate the brown effect, but it remains. It may be a connected of 1st dev temperature but I'm not clear on this one yet.

    Question - will there be a way to remove/neutralise this brown tone if I have to accept it as a byproduct of the process?

    PROCESS

    R09 + Na2S2O3, KMnO4/H2SO4 bleach, Foma Clearing bath, Light, R09 or Dokumol, Fix with Tetenal hardener.
     
  2. BMbikerider

    BMbikerider Member

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    I would have thought the final fixing bath would have removed this, are you washing for sufficient time?
     
  3. mr.datsun

    mr.datsun Subscriber

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    Well, I'm running many tests so I may not be as rigorous with the wash as when first I started - but I'm doing the Ilford 5, 10, 20 inversion rinse method. I use a qty of water roughly commensurate with the qty of dev I use. And that is 75ml. My inversions do get faster towards the end of each one hour development session.

    I have a fix bath which I use for 5 minutes - to maximise on the hardener as much as for the fix. The five minutes is also the recommended fix time for that fixer. I could run the next test with a more considered and leisurely inversion technique. And start with a fresh fix mix.

    Where does the brown come from? Is it a sepia side-effect from some uptake of the sulphur in the bleach? And if so should the fix remove that?

    The brown isn't a strong sepia effect just a warm brown tone that I don't much like.
     
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  4. Rudeofus

    Rudeofus Subscriber

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    It should be easy to determine which step of your processes brings about this brown tone. Run some test clips through only part of the process and inspect. Brown tone can come from various sources including Sulfide, very small grains, bleach precipitates, ...
     
  5. avortex

    avortex Member

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    The same happens to me. I don't use Rodinal for reversal processing for this very same reason. That brown tone is awful...
    No prblems with the other developers: Dokumol, Neutol,... I'm going to try D11 next time.
     
  6. johnielvis

    johnielvis Member

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    That may be just an extra haze of silver on the transparency and could be cleared with the very dilute ferricyanide bleach/fix bath. try it--give a dilute bleaching to half of a transparency and see if it cuts it. It may be caused by physical development going on in the process--dissolved silver in the solution is deposited on emulsion silver.
     
  7. nickrapak

    nickrapak Member

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    The second developer determines the tone. In fact, you can use straight sodium sulfide as the second developer to get a nice sepia tone. I would assume that the any developer with sulfur in it would deliver a similar brown tone.
     
  8. mr.datsun

    mr.datsun Subscriber

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    >johnielvis

    When you say a haze of silver, do you mean reduced silver? Would the silver be brown? You mean Potassium Ferricyanide?

    >nickrapak

    You'd think so, but substituting Dokumol for 2nd dev does not seem to help. Does R09 have sulphur in it and Dokumol not? Dokumol/Dokumol is more neutral than R09/R09 or R09/Dokumol.

    >avortex

    At this moment, Rodinal seems to have something special going on as a reversal developer that I haven't got from elsewhere and that I'd maybe like to use if I get can rid of the warm tone.

    >Rudeofus

    It's not there that I've ever seen in my 35mm R09 negs or when I stop my current reversal process and fix at neg. stage. I'm not sure where else I can stop the process and inspect the results. After bleach and clearing there's nothing useful to see, is there? Unless the fix causes the problem.

    Thanks for the responses. I can't help thinking that it's some kind of sepia effect going on at the bleach stage. If there's no known way of getting rid of sepia tone, I'll go back to testing. I think I'll make fresh fix and check my two processes again, removing any temperature variation factors, first.
     
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  9. brucemuir

    brucemuir Member

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    Stick with it my brother!
    I for one am encouraged that you are plugging away til you get it.

    I gave up awhile ago due to low contrast but will get back to testing this summer.

    Tip o the Jar to ya mate!
     
  10. johnielvis

    johnielvis Member

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    yes--metallic silver. very fine deposits of silver are sometimes caused by physical deveopment going on when there is silver solvant in the developer. Also, maybe incomplete bleaching may leave very very fine silver which gets re-developed in the second development or serves as sites for physical development during second deveopment.

    Very fine silver can be brown or provide other colors too. It's sometimes called "dichroic fog" when it's unwanted. With reversal, it's more of an overall haze of developed or deposited silver.

    Yes, potassium ferricyanide bleach plus hypo...plus a final hypo--standard bleaching process to clear any deposits away and brighten the highlights. If it's silver, this will get rid of it. If this doesn't work, then it's some kind of stain--perhaps from the bleaching step, perhaps from the second deveopment. Perhaps from an interaction between bleaching and second development.
     
  11. Rudeofus

    Rudeofus Subscriber

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    As I wrote there are many things that can cause the brown tone. If the bleach somehow forms Sulfide or precipitates MnO2 you should see that very clearly.
     
  12. mr.datsun

    mr.datsun Subscriber

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    Rudeofus. What would it look like, what should I look for?
     
  13. Alessandro Serrao

    Alessandro Serrao Member

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    mr.datsun: what about using dithionite as a redeveloper? Do you still get that brown tone?
     
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  15. mr.datsun

    mr.datsun Subscriber

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    Alex. I haven't used the dithionite, at all yet. I was told by Tofek that it gave brown tone reversals at which point I put it the bottom of my To Try Next list. But I should try it. Did you it?
     
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  16. Rudeofus

    Rudeofus Subscriber

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    There are methods for getting rid of MnO2 stain, while Ag2S is almost impossible to remove. Tiny Silver crystals can be bleached away with C41/E6 bleach (which won't touch Ag2S). This would give you some indication what kind of stain you got. Needless to state that you only need to check for MnO2 right after the bleach step.
     
  17. Jim Taylor

    Jim Taylor Member

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    I've literally started reversal processing B&W this week, and my first results were not perfect (lack of contrast on FP4+) but certainly there was something usable (accidentally overexposed the film by 1/2 stop - maybe that's it?)!

    I've done a lot of reading and seem to come across a couple of conflicting ideas regarding potential brown staining caused by a KMnO4 + H2SO4 bleach. Some methods suggest that this stain can be cleared using a Na2S2O5 solution (not sure if this is what's in the Foma clearing bath you use) but some methods suggest that Na-metabisulphite will NOT work, and instead one must use potassium metabisulphite.

    Now, as I mentioned, I've started playing with B&W reversal this week and I used a KMnO4 + H2SO4 bleach with a NaS2O5 clearing bath and it worked fine... perhaps the staining issue is therefore dependent on the age of solutions?

    I don't know if there's anything useful in my musings, but maybe it is worth checking/changing your clearing bath and see if that eliminates the problem? BTW - my method (at this early stage) is an almost direct implementation of that in Jens Osbahr's pdf (freely available online - and linked to on here), in which Rodinal is used as the 1st & 2nd Dev. - seemingly without any significant brown-tone issues. The only change I made was that I used Ilford multigrade as the 1st and 2nd dev. and like I said, slight lack of contrast (and possibly low D-max) - but worked with no staining.
     
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  18. davedm

    davedm Member

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    I see that Jim beat me to this post, but I will let this be here for the link and clearing bath suggestion.
    ----------------------------------------------------------------------------------------------

    This could indicate too strong bleach or rather incorrect bleach to clearing bath intensities.

    What is the composition of the bleach you are using ? Duration of bleach ?
    Do you have access to sodium metabisulfite (Na2S2O5) other than foma kit? (To be used as clearing bath)

    Please try using R09 as both first and second developer.
    if you are using Ilford bleach recommendations, reduce the strength to half (see this method http://home.snafu.de/jens.osbahr/photography/reversal_processing/osbahr_reversal.pdf ).

    If you have access to sodium metabisulfite, use it as recommended in osbahr pdf => 1g in 260ml and clear for two minures. Increase clearing bath time if brown tone remains.

    I have developed Ilford FP4+ as per the above instructions and got very good results. Will post scans after I receive them.
     
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  19. mr.datsun

    mr.datsun Subscriber

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    JIm, thanks for the ideas. And for the first time, I realised that the Foma clearing bath does have the contents printed on it. It's Sodium Pyrosulphide which I've never heard being used anywhere so far.

    I always planned to switch to NaS2O5 once the Foma kit was done. So I'm going to do it now as I'll have to get used to using it anyway.

    It was re-reading Osbahr that made me decide to go back to Rodinal and give that another shot.

    It seems that the low contrast is the bugbear of all home reversal processes. Are you using the chemical fogging agent?
     
  20. mr.datsun

    mr.datsun Subscriber

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    Yes, I'm trying sodium metabisulfite next time.

    With regards the Foma bleach, I only know that it's Sulphuric acid and Potassium Permanganate and have no idea of the strengths of the individual components. When the current Foma kit run out I will be mixing my own bleach.

    I have used R09 as both first and second. I switched to Dokumol to test whether the 2nd R09 was contributing to the brown tone.

    I've also noticed in my last test that doubling the hypo in the 1st dev apparently served to remove the brown tone (at least with the R09/Dokumol). But the two tests images were quite different in their ratio of dark to light , so I do need to confirm that.

    Look forward to seeing your scans.
     
  21. mr.datsun

    mr.datsun Subscriber

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    Rudeofus. Sorry to be dim but I don't know how to check for MnO2 stain after the bleach stage. After the bleach and clearing stage the remaining positive image is always a milky light yellow-green until it has been developed. Or is that what you mean? There are no images that capture this stage in the process to refer to, that i have seen. But I found this one from when I was using a makeshift reel and taken during re-exposure:

    afterbleach.jpg
     
  22. mr.datsun

    mr.datsun Subscriber

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    To be clear, I do not think I'd describe my warm brown positives from R09 as stained. I would merely say that the silver image has a warm brown tone. In that sense I do not think that it qualifies as what Osbahr calls a stain – due to incorrect clearing.
     
  23. Rudeofus

    Rudeofus Subscriber

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    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.
     
  24. Steve Roberts

    Steve Roberts Member

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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

    bwslides003.jpg bwslides002.jpg bwslides006.jpg bwslides007.jpg bwslides008.jpg Copy (2) of bwslides001.jpg
     
    Last edited by a moderator: May 23, 2013
  25. mr.datsun

    mr.datsun Subscriber

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    Rudeofus. Thank-you for the very clear answer and methodological approach to investigating the problem. That's just what I needed!
     
  26. johnielvis

    johnielvis Member

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    These appear to be missing dark dark dmax. I know what you mean about having to see them in person--scanners and digicams don't capture all of the meat. That's why they look so good--so hyper-real in person. I'd be interesting to check your process against others--same film, same exposure but different processes to see the differences. The thing is the person that comes up with the process has different techniques/equipment to develop--different water. different ambient temperatures, different reflexes--the differences in people, equipement and other things results basically a different process, even if the chemicals, times and temps are the same. So dupilcating anothers process is not reliable. it can result in "I tried it and it don't work. Followed the instructions to the letter, too." This seems to happen quite a bit.