What's this spot?

Discussion in 'B&W: Film, Paper, Chemistry' started by jgcull, Jan 23, 2008.

  1. jgcull

    jgcull Subscriber

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    I thought it was something I could wash off the negative, but it's not. It looks like a stain, maybe? Does it look to you like something I can fix? I'm sure you see it, but it's in the bottom right corner.

    Thanks.

    Janet
     

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  2. Rich Ullsmith

    Rich Ullsmith Subscriber

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    Really looks like a water mark, particularly if your film was dried while oriented this way. How long did you let it wash for the second time around?
     
  3. jgcull

    jgcull Subscriber

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    That's what I thought too, till I looked at the negative. It doesn't have that chalky look of residue from water. I use Hypo and then rinse 7 or 8 minutes. It sort of looks like a stain, but I'd love to find out it's a water mark. It could be fixed then, yes?
     
  4. 23mjm

    23mjm Member

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    I would rewash and photoflo it---see what happens!!!
     
  5. jim appleyard

    jim appleyard Member

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    Hi Janet, Yes, try a re-wash and rinse in Photo-flo. Pretty simple thing to do!
     
  6. jgcull

    jgcull Subscriber

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    Is photo-flo different from hypo clearing agent? I have hypo, but can order photo-flo if that's the ticket. Thanks so much for the info. I'll try it.
     
  7. thebanana

    thebanana Subscriber

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    Photo flo is quite different from Hypo. It's a mild detergent like substance that you use in very diluted form. I soak my negs for about 30 sec in it, remove the excess by running the film through my fingers then hang to dry.
     
  8. Photo Engineer

    Photo Engineer Subscriber

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    The spot is darker in the print, and therefore lighter in the negative.

    I think this is some other problem. It also looks like it continues out of the picture area. Please look outside that frame in the OP and in the adjacent negative area. If it is there, it is a development problem. Possibly water hit the film before starting processing, or a drop of stop bath.

    PE
     
  9. 23mjm

    23mjm Member

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    Nice catch PE the spot has less density on the neg not more like you would expect from a waterspot.

    That said I would still try a rewash---don't have anything to lose
     
  10. CBG

    CBG Member

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    Three different items - each with a different purpose

    You mention three different items - each with a different purpose. Make sure you don't get them swapped around.


    In order of usage:

    Hypo - the chemical that transforms undeveloped silver halides in the film or paper into a soluble or washable form, thus removable. Hypo's not perfect, but it's necessary. In paper especially, the transformed silver halides can still be quite tenacious, thus a washing aid can be helpful.

    Hypo Clearing Agent - (HCA) - HCA is a washing aid, and makes the results of the hypo even more washable or removable. Used mostly, but not exclusively on photographic papers. Sometimes used as adjunct to other photographic processes but don't get those confused with it's basic mission - washing fast and effectively. HCA is pretty simple, you can get it packaged off the shelf or even make it yourself with some water, Sodium Sulfite and Sodium bisulfite. (Regardless of whether you use HCA or not, after the hypo and HCA, you always wash the film or paper - follow the directions for the material you use. Time, changes of water and temperature are all important.)

    Photo-flo - essentially a very pure detergent/ surfactant mix, if I recall correctly. Used after the wash to help the water on the film sheet off so that water droplets and the like do not leave drying marks on the film. PE and others warn that household detergents have deleterious additived that may not be healthy on films. Use the real stuff and you'll rest easy.

    Best,

    C
     
    Last edited by a moderator: Jan 23, 2008
  11. Photo Engineer

    Photo Engineer Subscriber

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    I agree. It cannot hurt. I might do the entire fix, wash and photo flo thing.

    PE
     
  12. jgcull

    jgcull Subscriber

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    Do you always use photo flo at the end of your processing?
     
  13. Sirius Glass

    Sirius Glass Subscriber

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    Yes with black and white.

    Steve
     
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  15. Photo Engineer

    Photo Engineer Subscriber

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    The color stabilzer also contains photo flo.

    I never use any rinse after the fix step for B&W or color, just wash and then use either photo flo (B&W) or Stabilzer (color).

    PE
     
  16. jgcull

    jgcull Subscriber

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    Here's what I do. Please tell me if it's wrong. Soak in water briefly, develop, stop with water, fix, rinse 1 minute with water, agitate lightly 2 min. in hypo clearing agent (to reduce rinse time), rinse 6+ minutes with water, final rinse in distilled water. (I guess I'll try adding photo flo to the process and see if I can see a difference.) I used to have a chalky-ish residue till I started doing a final rinse in distilled water. We have well water.

    Janet
     
  17. Photo Engineer

    Photo Engineer Subscriber

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    Janet;

    What you are doing seems fine. Photo Flo is like taking out extra insurance.

    PE
     
  18. dancqu

    dancqu Member

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    You do this:
    Pre-wet, develop, stop, fix, rinse, hca, wash, rinse.

    I do this:
    Develop, fix, wash, rinse.

    Developer: very dilute, one-shot.
    Fixer: very dilute, one-shot.
    Wash: 5-10-20 sequence.
    Rinse: Photo-Flo.
    Room temperature distilled water ALL solutions.
    I've also hard well water.

    An eight blade film squeegee is employed;
    makes for quick drying.

    A quick look; perhaps a light leak? Dan
     
  19. dancqu

    dancqu Member

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    Yes, no light leak. What format, 35mm? A big drop
    trailing down. What ever, it REDUCES density in
    the negative. Dan
     
  20. jgcull

    jgcull Subscriber

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    >>>What format, 35mm?

    No, 120.

    Dan, what does "5-10-20 (wash) sequence" mean? And what developer and fixer do you use? Just curious because you said, "very dilute".
     
  21. jlehmus

    jlehmus Member

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    I'm seeing such weaker density spots on my 35mm negs now and then. Lower left corner in the attached image. It is a scan from a straight print.

    The spots are usually evident only in larger areas of uniform density, such as overcast skies. They look just like minute drops of water left on the negative after wiping. As they appear only on sloppily washed negs, I've imagined that the stain might be caused by some chemical trace (fixer?) left on the emulsion surface to "eat" some image silver during drying.

    I dry my films in the darkroom, where humidity is high and temperature low (during the night). Even in the summertime it takes well overnight until the negs are completely dry.
     

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  22. Photo Engineer

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    If anything 'eats' silver, the resultant spot on the print would be darker.

    PE
     
  23. dancqu

    dancqu Member

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    I refer to the Ilford 5-10-20 sequence. For much discussion
    of the subject make a Forum Search for 5-10-20 .

    I home brew all my chemistry. My fixer is unadulterated sodium
    thiosulfate fresh prepared each session. There is no 'magic
    concentration' at which fixer works though there need
    be enough of the actual chemical to do the job. Try
    20ml of ammonium thiosulfate concentrate in the
    necessary volume of solution. Should fix most
    any roll of 120. Allow 10 minutes. Dan
     
  24. jlehmus

    jlehmus Member

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    That exactly is the case, both in Janet's sample and in mine, lower density on the negative. I'll look at it in detail on my part and then report back.
     
  25. Photo Engineer

    Photo Engineer Subscriber

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    It could also be less development. We cannot be sure at this point, but 'eating' the silver is slower after it is formed.

    PE
     
  26. LisaU

    LisaU Member

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    Hi Janet,
    Now I don't know if it's the same thing but it definitely is the same size and shape of spots I was getting on a few rolls. I even asked for advice here: weird teardrop spot
    I tried all the advice that was noted but to no avail. I also did a second to last wash in distilled water and then a final with distilled and photoflo. Finally I tried to chalk it up to condensation. Then as a last ditched effort, I carefully surveyed my wet roll as it came out of the wash, before drying, and found no spots. Then after drying, spots appeared, so it had to be in the drying. Then I checked my film every 10 minutes while it dried (yes, as exciting as watching paint dry) and found that if I had at least a medium sized water drop sticking to the non emulsion side, the emulsion side tended to dry slower in that exact spot but in a teardrop shape. I then read that if that happens, the gelatin can tend to migrate out to the edges of that spot making a permanent mark. Maybe because it is cooler in that spot for longer? I now find that if I make sure there is absolutely no water drips hanging on the non emulsion side, there are no pear shaped drops after it all dries. There it is, my non-tech explanation for my spot problem. I hope it helps ya. Can any one shed some light as to why this happens?