Black and white slides / reversal process diagnose problems?

Discussion in 'B&W: Film, Paper, Chemistry' started by NDP_2010, Dec 13, 2012.

  1. NDP_2010

    NDP_2010 Member

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    Hi,
    Try out reversal process for the first time I am using Ilfords information that can be found on google www.ilfordphoto.com/Webfiles/20061291034093.pdf

    basically, 10g /L thiosulfate in first dev; 1% sulfuric acid + 2g/L potassium permangenate bleach; 25g/L metabisulfite clearing, expose, develop, fix

    I first had problems with the slide being too dark, ie highlights were very dense. I exposed the film for about 1min close to 2 fluro tubes. Im not sure if this was exessive exposure as I also repeated the process again further away and for 45 seconds and it also gave dark results. Should I use a weaker light source or is this a problem with not developing the film initially for long enough? (I developed the film for 8 minutes= I am using HP5+ which is close to normal development time for negative)
    Ilford reccomends 12 minutes for panF so I am unsure if i should dev hp5 for longer.

    On my second attempt all seemed fine untill 2nd dev, when i poured it out it was tinted with grey. I later found out that this was most likely the silver halide as my slide was completely clear. What can cause this? Is it possible I did not wash out the clearing solution for long enough and it some how cleared off the emulsion during development?

    Also, how long is it possible to keep first and second developer- how many rolls can be expected from these? Similar to normal negative development or a shorter lifetime?

    Many thanks for your help

    --------------
    summary of questions

    -is using two fluro tubes (similar to ceiling lighting) too strong for second exposure?
    -what can cause the emulsion to come off during second development? (contamination from clearing solution?)
    -what is the lifetime of the bleach, clearing solution and developers in reversal processing?

    :smile:
     
  2. railwayman3

    railwayman3 Member

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    I've used Ilford's method in the past with good results, with the slower films. Not sure about the developing times for HP5+, but I would have thought that a similar time to Pan F would be a good starting point.

    As Ilford say, 2-4 times the basic second exposure should not cause problems (better more than too little time), but excessive exposure or sunlight can cause problems.

    I recall once that the bleach stripped the emulsion completely!
    (Sulphuric acid and permanganate is quite strong stuff) I can't recall the type of film, might have been an older film with a softer emulsion, but IIRC I think that I might have given the film too long in the bleach (just to be on the safe side? :sad: ). Best to stick to the recommended times.

    Not sure about keeping times of the solutions..with all processing I tend to discard the working solutions after the session, even if it means storing up sufficient films to use up the chemicals economically.

    Hope you sort out any problems...projected B & W slides look amazing if well done.
     
  3. nexus757

    nexus757 Member

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    The potassium permanganate bleach makes the emulsion extremely soft and fragile. I have seen the emulsion essentially melt away in the second developer as well. A couple of suggestions: Use Kodak D-19 with the thiosulfate for your first developer and unaltered D-19 for the second developer. Keep temps near 68F. Do not let the developer get too hot. Also, you may want to cut back slightly in the amount of potassium permanganate used to make the Solution A bleach. If reversing an old-school emulsion like Efke/Adox the permaganate should be roughly cut in half (from 2g to 1g per 500 ml water). Do not alter the strength of Solution B. Do not worry about "over exposure" prior to second development. Bring it out in the light and thoroughly expose the emulsion taking care not to scratch it. Always use a hardening fixer after second development.
     
  4. johnielvis

    johnielvis Member

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    Looks like that bleach caused the weakening/emulsion problems--Use dichromate bleach if you can, it's way better--that will take away one of the variables/problems.

    reversal processing has many variables and it's best to keep them to a minimum by using the simplest chemicals and figuring out how to get them to work together in your process.

    One variable and source of never-ending trouble is the hypo in the first developer and the various first deveoper concoctions that people seem to come up with. You need no hypo in the first developer...you can use straight d-19 with no hypo--or d-19 cut 1:1...then you can use the SAME developer for the second development. If you stick to a simple developer with no "monobath properties" you will have a controllable, repeatable process.

    There are no set processes and everybody seems to have their own that work for them. hp5 is done successfully using only d-19 or d-19 1:1 with water, dichromate bleach, sulfite clearing bath, 2 minute reversal in regular roomlight/flourescent fixture, and using the same d-19 as second developer.

    ANY developer can be used, so long as it's strong enough, as a first developer with NO hypo....paper developer is nice and strong stuff like d-19.

    Eliminating the "hypo variable" in the first developer and using a more reliable/gentle bleach, will allow the process to be "dialed in" with a minimum of time wasting failures.
     
    Last edited by a moderator: Dec 13, 2012
  5. Alessandro Serrao

    Alessandro Serrao Member

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    If I recall correctly, gelatin melts because there's a huge shift in pH between the first developer and the bleach. It's not because of the permanganate. It does nothing to harden the emulsion, contrary to what dichromate does. So keeping that shift to a minimum will solve your problem of gelatin melting.
    Also using a temperature of 18°C helps.
    Try using the first developer with a diluition factor like 1+3 or 1+4 and lengthen the developing time accordingly . This will slightly lower the pH. Then try to cut the permanganate in half. The idea is to find the bare minimum of each and every chemical specimen that will work one-shot and will avoid ruining the emulsion.
    Try also to add some glutaraldehyde (such as Rollei Rbm5) in a bath between the first developer and the bleach, sort like of an hardening stop bath.
     
  6. NDP_2010

    NDP_2010 Member

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    Thankyou for the quick and detailed replies.

    Do you think lc29 is a suitable developer for this process or possibly rodinal?

    Any other advice would be much appreciated. I am currently purchasing some dichromate and possibly try out some slower films.
     
  7. Alessandro Serrao

    Alessandro Serrao Member

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    I would only use high-contrast developer such as paper developer. Also Kodak D-19 is excellent. I've had very good results using Tetenal Eukobrom for instance. I think any paper developer can do.
    Negative developers are not convenient in that you have to tweak them in order to obtain a decent contrast.
    You sure can do it, for instance adding some sodium carbonate or some sodium hydroxide.
    With paper developer you eliminate one possible variable (hopefully choose and use the same developer in your tests).
     
  8. Athiril

    Athiril Subscriber

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    I gave up on permanganate, and use a dichromate bleach, never looked back. Reliable bleaching every time.
     
  9. Oxleyroad

    Oxleyroad Subscriber

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    I concur with both Alessandro on the developers as I have successfully used both, and Athiril on the dichromate bleach. I too have never looked back since moving away from permanganate bleach.
     
  10. NDP_2010

    NDP_2010 Member

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    Thanks oxley,

    if using high contrast developer (possibly multigrade paper devloper has been suggested by some), how long would I do first and second developments on film such as fp4 or hp5?
     
  11. Oxleyroad

    Oxleyroad Subscriber

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    I have not run any Ilford film to date as reversal, don't have much of it. I have run Foma negative and reversal, Shanghai GP3, Orwo UN54, Silvermax and Kodak Tri-X reversal as well as Kodak colour Vision2 cine neg film. The Silvermax and colour negative film needs longer developing times than the other films, so I do not dilute the developer and run for the same times as below.

    I shoot all my film at box speed, but the colour neg at 1 stop under.


    I cannot give a time for multi grade developer, but my times for D19 dilute stock 1:1 at 23degC which I am using right now with Foma R100 both 35mm and 16mm.

    Dev 1- 3min 30 const agitation
    wash
    bleach - 60 sec const agitation
    wash
    clearing bath - 60sec const agitation
    wash and open tank to dark room lighting 2x 75W globes for 2 to 5 mins
    Dev 2- 90 to 120 sec. Same developer as Dev 1
    Wash
    Fixer - 2 mins
    wash

    I have run many test strips of bracketed film, and I do this for each new developer or when I store mixed developer for more than a fortnight just to confirm my times.

    Trust this helps.
     
    Last edited by a moderator: Dec 19, 2012
  12. NDP_2010

    NDP_2010 Member

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    thanks :smile:
     
  13. NDP_2010

    NDP_2010 Member

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    Had a look for recipe for dichromate bleach,

    what concentrations are people using (2g/L?) or more concentrated.


    Thanks.
     
  14. NDP_2010

    NDP_2010 Member

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    Also, is thew sulfuric/dichromate bleach one shot or can it be reused multiple times?
     
  15. NDP_2010

    NDP_2010 Member

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    anyone? :tongue:
     
  16. Tofek

    Tofek Member

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    You can use 5g/L of potassium dichromate or 10g/L if you want a stronger bleach. It's reusable a few times, but the amount of oxydant Cr2O7(2-) isn't unlimited since it decreases each time you bleach. Add about 10mL of pure H2SO4.
     
  17. NDP_2010

    NDP_2010 Member

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    thanks :smile:
     
  18. Athiril

    Athiril Subscriber

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    Sorry multiple times. I never bothered being accurate in measuring dichromate bleach, I just inspected until the bleaching was done, if it was too slow for my liking I increased the strength, you need very little sulphuric acid in my experience.

    I've done some good Tri-X 1600 and 3200 slides with HC-110 as first dev using Thiocyanate.
     
  19. Gerald C Koch

    Gerald C Koch Member

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    When the slides are too dense then either the film requires a lesser EI or the time in the first developer needs to be increased. If the slides are too thin then the film requires a greater EI or the time in the first defveloper needs to be shorter. Film for reversal processing is usually not shot at box speed. Remember this is reversal processing and things work sort of backwards. The exact EI varies from film to film. If you are not following a recommended procedure for a specific film then you will have to bracket at first to determine what EI is best.

    A 1 min exposure to a 250W photoflood lamp should be sufficient for re-exporure. When using SS reels the film can be left on the reel. Just hold it approximately 2 feet from the light and move the reel so the light can reach all portions of the film. A re-exposure is not needed if you use a fogging developer as given below.

    The second developer or a fogging developer goes to completion and so over development is normally not a problem. A simple re-useable bath containing 100 g of sodium carbonate and 2 g of thiourea per liter can be used instead of a conventional developer. This bath can be saved and reused several times. A commercial sulfur based toner can also be used. Both baths yield pleasing sepia colored slides. The film should not be fixed again after either of these baths but should be washed thoroughly. The T-Max films do not give good results with with thiourea or sulfide developers.
     
    Last edited by a moderator: Feb 16, 2013