Developing different films together

Discussion in 'B&W: Film, Paper, Chemistry' started by thomsonrc, Feb 16, 2008.

  1. thomsonrc

    thomsonrc Member

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    I remember reading when I started developing film that you mustn't develop different types of film together in the same tank. It didnt say why. I have always follwed this advice, but occasionally I have found that two different films need the same development time - is it safe to do them together? Or is there some reason other than timing for not doing this?

    Thanks

    Ritchie
     
  2. sun of sand

    sun of sand Member

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    I do it. I just did Plus-X and TMAX sheet film
    keep times straight and I have no idea what could possibly go wrong
     
  3. Ian Grant

    Ian Grant Subscriber

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    Recently I developed Tmax400, FP4 and HP5 together, in Pyrocat HD, with no problem. My times for these films would only vary very slightly if I process separately.

    However I made a huge mistake processing my first rolls of Fomapan200 alongside Tmax400, as I've since done some Zone system tests and discovered that my dev time for Fomapan 200 should be 10 minutes and not the 15 minutes I gave them. 15 mins was equivalent to N+2 so the negatives were excessively contrasty.

    Ian
     
  4. Mark Antony

    Mark Antony Member

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  5. Ian Grant

    Ian Grant Subscriber

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    If you took the films to a commercial B&W lab they'd all get developed together for the same time, unless you pay a premium for hand processing.

    Ian
     
  6. wobsy

    wobsy Member

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    Any B&W film(except chromo) - any size - any speed - Acros - Tri-X - Delta 400 - whatever your favourite - use Prescysol. Put them all in together and give 10.5 minutes. Excellent.
     
  7. Ian Grant

    Ian Grant Subscriber

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    wobsy Prescysol is what?

    Isn't it an imitation of Pyrocat HD.

    Ian
     
  8. Konical

    Konical Subscriber

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    Good Afternoon, Ritchie,

    As others have indicated, developing different types of B & W film in the same batch usually isn't any problem at all as long as they require the same or nearly the same developing time.

    If you are well organized and careful, films with significantly different developing times can be managed in one batch. Be sure that the film requiring the shorter time is on the top reel (or reels) in the tank. When its (or their) required time is complete, remove the appropriate reel(s), transfer it or them temporarily to a film washer, and continue to the end of the required time for the remaining film. OBVIOUSLY, the lights must be turned off during the transfer procedure and thereafter until all the reels are back in the covered tank for the fixing step, which will ordinarily be the same for all the film types. Should the films require differing fixing times (longer for T-grain, for example), just favor the longer time for all of them; an extra minute or two in the fixer shouldn't matter. I've used this procedure at various times without difficulty, BUT I don't advise doing it if tired or distracted; you have to do everything carefully and be very comfortable working in complete darkness for part of the time.

    Konical
     
  9. thomsonrc

    thomsonrc Member

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    Too complicated for me, I just developed one film tonight and forgot to put the central core in the tank, so its all fogged.

    Thanks for all the replies, I will mix up the films if the time is the same in future,

    Ritchie
     
  10. MattKing

    MattKing Subscriber

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    One further thought. If you are going to do this, you should make sure that you have plenty of developer in the tank. I would expect that if you are working close to capacity, the longest developed film might use an unequal share of the developer's activity, before the other film(s) is/are added.

    Matt
     
  11. Dave Miller

    Dave Miller Member

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    That's my favourite too. It produces negatives that are very easy to print.:smile:
     
  12. Konical

    Konical Subscriber

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    Good Morning,

    "I would expect that if you are working close to capacity, the longest developed film might use an unequal share of the developer's activity, before the other film(s) is/are added."

    Matt--You are probably correct. I think I avoid that most of that problem by starting with all the films and then removing early any needing a shorter time. For example, if one film needs seven minutes and the other needs nine minutes, I suspect that, with most of the development is complete after seven minutes, any extra pep available to the nine-minute film probably makes little difference. At least I've never encountered a problem. Obviously, there could be a difference if the developing times vary widely, say one film at five minutes and another at fifteen. With that great a discrepancy, I'd probably develop separately anyway, since the time working in complete darkness would be considerable.

    Konical
     
  13. wobsy

    wobsy Member

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    Hi, sorry for the late response. You may be right, I don't understand the formula of Prescysol, there is information on the web and it is available in the UK. Having said that I know there are a number of very satisfied customers in the US. Further, I use the brew myself and dev whatever film I may be using at the same time, 35 or 120 together if necessary. The only occasion when a different developer might be used is if push processing is required.
     
  14. Smudger

    Smudger Member

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    Different films together-my method..

    I've used this method for years,with good results.
    Assume you have 3 emulsions :A ; needs 14min, B : needs 12min ,C:needs 8 min.
    Prepare chemistry for 3 films.
    Load 3 reels and put B & C films in a spare tank.
    Start process with film A.
    At minute 2, add film B.
    At minute 6 , add film C.
    By minute 14 you will have 3 films correctly developed,and they can all be stopped and fixed together.
    Obviously you need a darkroom to use this method..
     
  15. rippo

    rippo Member

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    that's a lot of fiddling. if i want to develop films of different speeds and/or types together, i'll just use a two-bath developer. from asa 25 to 400, it all works well because development time is not a variable. Anchell/Troop TD-200 or divided D-76 is what i use. you can't push or pull the film, and you get some highlight compensation using this method, but you get proper film speed (aka shadow development). i've done Adox CHM 400 and Ilford Pan F+ in the same tank.