Problem developing 120 film

Discussion in 'B&W: Film, Paper, Chemistry' started by LucianN, Aug 6, 2008.

  1. LucianN

    LucianN Member

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    Maybe this was posted before but i am a new user...
    So, these days i was developing a B/W film in a Pentacon Triplex tank with a corex band. The method was 30 seconds agitation (rotation of spool) in the first minute and after yhat every 10 seconds of the next developing minute. After fixation and final washing i noticed some dots on the negativ film (trasparent ones) thrue the emulsion where the image is. The dots are just on the side of the negativ... sometimes clearly visble sometimes absent... on the same roll of film. Could someone explain the nature of those dots and how to get read of them? Mention: those are not air bubbles, the film beeing pre-wetted befor loading into the spool (air bubbles create black spots on negativs as i know).
    Tnx for any suggestions!
    Regards LucianN
     
  2. Ian Grant

    Ian Grant Subscriber

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    I've seen clear dots very few times in about 38 years, but there are two possible causes.

    1. The tank was contaminated, maybe hadn't been washed properly and fixer has crystallised getting into the developer.

    2. Far more likely - small particles of iron in the water used, these react with the fixer causing it to bleach the image, you can filter the water & solutions to prevent this.

    Welcome to APUG by the way :D

    Ian
     
  3. Trevor Crone

    Trevor Crone Member

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    Another possible cause is dust settling on the emulsion at the taking stage. These of course will print as tiny black dots.

    Out of interest are there a few or many clear dots and are they really tiny or large?

    Again welcome to the wonderful world of analogue.
     
  4. LucianN

    LucianN Member

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    The tank was brand new (unvraped form the original box) when those spots appeared. And also after each developing the film is removed from tank and washed (stop bath in wather) afther that put back in and fixed... again out with the film for final wash... meantime the tank lays is water.... So contamination wiht fixer i gues is out of discuttion. The other hand dots are aligned in what seams to form a line... No random spots are present on the negativ... Is it possible to be caused by the corex band??? The pattern is likely... Butt i never see before such a problem to any other photographers using the same tank and corex band.
    Mention: The corex band was not so tightly riped around the spool... to let the chemycals flow easely betwen the corex band and the film... others did the same and with good results...
    Thanks for welcome wishes and for the answere Ian!
     
  5. LucianN

    LucianN Member

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    Trevor - the dots are tiny at beginning ... groving to a point and after that decreasing again. The dots are trasparecies in the negativs at the margin of the image. So dust is not the cause of that.
    Thank you for welcoming me... really a wonderfull world:smile:
     
  6. Ian Grant

    Ian Grant Subscriber

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    If it's only one film perhaps it's a coating fault.

    Ian
     
  7. LucianN

    LucianN Member

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    no.... multiple films same problem
     
  8. Ian Grant

    Ian Grant Subscriber

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    What make of film ?

    Ian
     
  9. LucianN

    LucianN Member

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    The film is Fomapan 100 ISO, but also developed T-Max 35mm with smaller amount of dots... I dought T-max is low quality on emulsion:| Could it be a mechanical problem.... corex band scratching slowly the emulsion on the film while i am agitating the spoll... ??? Still never see this kind of troubles before.
     
  10. Bob F.

    Bob F. Member

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    Can you post a scan of the offending negatives?

    Cheers, Bob.
     
  11. LucianN

    LucianN Member

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    Sorry... my scanner is pretty old ColorPage HR7 (Genius)... I could try but only tomonrow or later tonight i will upload them. Don't expect any quality...:sad:But hope to make the dots visble. I'll try scann the film today.
     
  12. Ian Grant

    Ian Grant Subscriber

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    Lucian, you should try a different developing tank, maybe it is the Corex. That style of tank was dropped a great many years ago by most manufacturers.

    Your only going to find the cure by trying different options.

    Ian
     
  13. LucianN

    LucianN Member

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    If a find one... i would... I'll try to order from internet if they'll send to me... In the stores are pretty absent these days... here...
     
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  15. Ian Grant

    Ian Grant Subscriber

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    If I was back in the UK I'd send you a Paterson tank, as I have some spare. Where about are you ?

    Perhaps someone else can help.

    Ian
     
  16. LucianN

    LucianN Member

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    Romania :smile: No e-bay... no on-line shoping :sad: Sad but true! Hope we will get over this and start be regarded as humans!
     
  17. Ed Sukach

    Ed Sukach Member

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    What was the composition/ strength of the short stop?

    In the past, I have had "pinholes" in film, caused by "recommended" acetic acid dilutions.
     
  18. Photo Engineer

    Photo Engineer Subscriber

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    Your post indicates clear spots. Air bubbles form clear spots on negatives, not black spots.

    Could you clarify this?

    PE
     
  19. LucianN

    LucianN Member

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    @Ed - Stop bath = pure simple water.... no acid solution
    @Photo E - The film was pre-wetted in another tank...
     
  20. FotoGys

    FotoGys Member

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    Could it be caused by the possibly formed carbon gas in the emulsion when switching from alkali developer to acid stop or fixer.
    I never use a (acid) stopbath for this reason but plenish with a tank fully filled with water agitate 25 seconds and repeat this 3 times (total takes 1'30') before putting the fixer in the tank.

    Regards,
    Guus
     
  21. LucianN

    LucianN Member

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    Guus Thanks... but I am using watter as a stopbath. After the 8 minutes in developer I remove the spool with film from tank and put it in a bucket filled with watter for about 1 minute ... agitating in the same time the spool with film. After that i place back the spool in the tank (cleaned tank - washed) and fill it with fixer...
     
  22. Photo Engineer

    Photo Engineer Subscriber

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    In the OP, I believe you said you had black spots on the negatives. This is not indicative of air bubbles, but rather some contaminant in the developer itself, or something on the film from the water that causes black spots.

    So, something is not clear to me.

    PE
     
  23. Trevor Crone

    Trevor Crone Member

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    In his OP he said 'transparent spots' which is why I thought of dust settling on the film before/during exposure.
     
  24. Photo Engineer

    Photo Engineer Subscriber

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    Sorry, but I misquoted. Here is what I am referring to "air bubbles create black spots on negativs as i know". Air bubbles cause the white spots, not black spots and that is the comment that caused confusion with me. The white spots ARE probably air bubbles. Air bubbles don't cause black spots as he stated, and he thereby seemed to eliminate them as the cause of the problem.

    Sorry for adding to the confusion.

    PE
     
  25. panastasia

    panastasia Member

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    I too, think the clear spots are caused by air bubbles - I always tap the film developing vessel on the bench or counter to dislodge them, I thought everyone did this as common practice.

    Paul
     
  26. Thomas Bertilsson

    Thomas Bertilsson Subscriber

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    I can also relate to this. If it's along the rebate (edge) of the film, air bubbles get caught by the film spool so that no developer gets to that area. So when you fix your film, it will clear in those areas.
    You can help to remove these air bubbles by rapping the tank against a hard surface (preferably with a towel between to prevent damage on the tank or the surface) several times each time you agitate. Or, if you're using some other kind of tank (I'm not familiar with the Pentacon), agitate so that you dis-lodge those air bubbles.
    I have had this problem on occasion.
    - Thomas