Photo flow in developer

Discussion in 'B&W: Film, Paper, Chemistry' started by BobF, Jul 24, 2003.

  1. BobF

    BobF Member

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    In the thead "Mystery image" it has been proposed that the cause of the strange pattern found on some negatives may have been caused by photo flo carried over from poorly washed developing reels. I have wondered about this as I sometimes don't wash off the reels. Is this a probable or even a possible problem?

    I have also read threads wherein someone presoaks with photoflo or one person who even adds a dash of photoflo to the developer to even out developer. It has also been said that the reason Ilford recommends not presoaking (which I do even with Ilford film) is that the backing or emulsion has a little wetting agent included that gets washed away by presoaking.

    So whats the consensus opinion?
     
  2. Les McLean

    Les McLean Subscriber

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    I'm fairly sure that Ilford do not recommend presoaking because some years ago a well known British photographer had problems with uneven development that was traced to presoaking.
     
  3. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    I presoak 11x14" and 8x10" sheets to be processed in pyro developers and find I get more even results that way. I also presoak East European films that have a blue-green anti-halation layer, because the dye comes out better that way, and doesn't seem to come out at the fixing or washing stage, like the magenta T-max dye.

    I wouldn't use Photo-Flo in the presoak or developer, though I've heard of this practice.
     
  4. Ole

    Ole Moderator Staff Member Moderator

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    I presoak everything EXCEPT sheet film for tray development. But that's because my darkroom is leaking light, and I have discovered that the anti-halation layer protects the emulsion from exposure until the development is well under way. I will no longer do Maco 820c "AURA" in trays...
     
  5. garryl

    garryl Member

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    The only time I've used a wetting agent, in a developer, is in printing. I was experimenting with the Winchester formula. It is very simular to Dektol, except for adding a wetting agent. I quickly learned that it had to be a Non-ionic wetting agent(e.g. Edwal LFN). Every time I added Photo-flo to Dektol, I would get a tar like substance floating on the surface. The formula prove no better than plain Dektol.
     
  6. Jorge Oliveira

    Jorge Oliveira Member

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    A long time ago I've added some Agfa wetiing agent (forgot the name) to developer.
    I cannot comment in the results, since there was no significant difference. Due to that, I stopped using it.

    Jorge O
     
  7. Aggie

    Aggie Member

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  8. JHannon

    JHannon Member

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    I am no chemist but I would think that if a wetting agent (detergent?) were added to the developer (from poorly washed reels), it might "bubble up" during agitation and cause some strange effects with the developer. Just a thought..BobF may be on to something here.

    I find the metal reels easier to wash than the plastic types.
     
  9. clay

    clay Subscriber

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    I attended a Mark Citret workshop a while ago, and he makes it a practice to pre-soak all of his tray developed 4x5 film for 5 minutes in a weak photoflo solution before putting the sheets in the developer. He has excellent negatives (and prints!!) with no signs of problems. I did the same while in the workshop and did not have any uneven development problems. I'm guessing it all depends on your particular habits and local water conditions. Heck, I even hear that some people get good negs from PMK. If you can do that, then photo-flo should be a cake-walk!

    Clay

    P.S. Mark's url is www.mcitret.com He is an excellent photographer, teacher and all round nice guy.
     
  10. sanking

    sanking Member

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    I pre-soak all films, roll film and sheet, for five minutes at the temperature of the developer. Never used PhotoFlo but often add a pinch or two of sodium carbonate to open the gelatin a bit and speed up induction.

    Can't say I have never had any problems in develoing film, but never have had one that I could blame on pre-soaking.

    Sandy
     
  11. BobF

    BobF Member

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    In my original question I asked "so what's the consensus opinion"? and so far we are all over the map on presoaking and except for photoflo in Dektol no real known problems there.

    This is just about what I have found in reading old threads. It doesn't seem as if any real testing has been done or else there are so many differences in everyone's proceedures that it is hard to pin down. It would seem that you would have to be mixing your wetting agent pretty rich to have significant carry over on unrinsed reels.

    The Ilford recommendations are intriguing though as there is so much evidence that presoaking is helpful or at the least harmless.

    Les - Can you remember more about that photographer that had streaking problems caused by presoaking.

    Just for the record I presoak with plain water just because I often use large tanks (1000ml stainless) and am concerned about the 30+ seconds for the chemical pour. I just do it habitually to be consistent even with small tanks. I really should do some testing.
     
  12. lee

    lee Member

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    I seem to recall that Ilford stated that they had put photoflo into the emultion and if you presoaked you could/would wash it out. With PMK, I add some photoflo so the film won't stick together. I don't see any reason to change after a lifetime of presoak.

    lee/c
     
  13. Aggie

    Aggie Member

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  14. Shesh

    Shesh Member

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    One more data point for BobF - I don't presoak my negatives since the b&w films I use (TMY, Delta 400) don't need it.
     
  15. Ed Sukach

    Ed Sukach Member

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    I remember the Ilford proscription against pre-soaking - "streaking" was not the concern - Ilford claimed that presoaking caused an unfavorable "swelling" of the emulsion prior to contact with the developer and the end result was a decrease in overall image quality, especially in acutance.

    I might be remembering incorrectly (sadly, it does happen at times) but I think I read much the same thing in a report from Agfa, and from one or two of the color chemical manufacturers.

    Anyway - I don't prewet/ presoak.
     
  16. fhovie

    fhovie Subscriber

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    I presoak larger formats because I believe it causes the developer to enter the emulsion at a controlled rate while replacing the water put there by presoaking. I agitate during proesaok - I also like the antihalation layer out of the mix. I also agitate by rapidly inverting the tank back and forth and then a radial spin before clunking it down to knock out air for each 5 second agitation. I wonder if gentle agitation interupts the laminar flow of chemical and if it replenishes exhausted developer as well. I have never had streaking or problems doing this. The effect of presoak on accutance is an interesting idea. It would be interesting to try some identical sheets and if the difference could be detected. - Frank
     
  17. mvjim

    mvjim Member

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    The problem that comes about with photo flo contaminated reels is that the reels do not allow the bubbles to escape and trap them against the films surface. With sheet film this is not necessarly a problem.
     
  18. Les McLean

    Les McLean Subscriber

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    [ Les - Can you remember more about that photographer that had streaking problems caused by presoaking.


    The photographer was a lady called Fay Godwin and the problem was streaking in even toned areas such as skies. At on point she had a sizeable number of undeveloped films that she would not process until the problem had been sorted. The final analysis was the the pre soak water was removing something when it was poured away so Fay went through the labourious process of pouring the pre soak water into a graduate containing the undiluted developer and refilling the tank with it. The main thing was that it eliminated the problem.

    Ed mentioned a similar problem with Agfa, I can verify that for John Davies another British photographer told me that he used Agfa 100 and had the same problem for a while and solved it in the same way as Fay.

    It was about 15 years ago that this happened .
     
  19. BobF

    BobF Member

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    [quote="Les McLean .....so Fay went through the labourious process of pouring the pre soak water into a graduate containing the undiluted developer and refilling the tank with it. .....[/quote]

    She must have been very convinced that presoaking was benificial to go through that much of a PITA. Thanks for the info Les. I was planning some test negatives (for lots of other reasons also) and will make sure to include some blah sky.

    BTW everyone, I filled a two reel SS tank with an over rich Photoflo mix (half cap in 500ml) then drained it and let it dry. I then filled with water and shook vigorously to see if it foamed from residual Photoflo. NONE ! I can not see how Photoflo carryover could ever be a problem unless plastic reels and tanks are a lot different. Someone ought to try this with plastic.
     
  20. Robert

    Robert Member

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    You don't need to put your photoflo in the tank. I use a small jug. I take the film off the reel soak it. Then with a gloved pair of fingers I wipe it. Repeat for each roll. If you're only doing two rolls it's not going to take much longer. The little jug I use is big enough to handle anything up to 4x5.

    I'm not sure how valid your test for carry over is. Doesn't matter if you can tell if it's there but if it reacts with the next batch of film. Used to be you didn't wash beer glasses with soap because the faint traces that remained in clean glasses would kill the head.