Strange grid pattern appearing on negs

Discussion in 'B&W: Film, Paper, Chemistry' started by labasarabas, Mar 25, 2011.

  1. labasarabas

    labasarabas Member

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    Hi everyone,
    I have been lurking around here, gleaning info for a few years, but i think this is my first post.
    On a recently processed roll of film, there is a grid pattern affecting the whole roll. It looks almost like a fly screen texture, and not in line with the film. It's at an angle. I'll try to attach an example.
    The film was plus-X 120 processed normally, and was just out of date. It travelled with me on a trip in the desert but was kept cool always. The only thing I can think of is some sort of texture from the backing paper . . . ?
    The first image is almost full frame 6x6, and the second is a detail.
    Anyone know what's going on??

    -cheers

    [​IMG][/url]
    bike by labas arabas, on Flickr[/IMG]

    [​IMG]
    bike_detail by labas arabas, on Flickr
     
    Last edited by a moderator: Mar 25, 2011
  2. labasarabas

    labasarabas Member

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    ok, I think I have a problem posting images. Will research and return.

    -cheers
     
  3. polyglot

    polyglot Member

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    Do let us know when you can post an example. I've had one roll come back with a very faint array of squares on it that don't correspond to anything I can think of.
     
  4. JBrunner

    JBrunner Moderator Staff Member Moderator

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    Just SWAG, because I haven't seen this before- one, it could be from the paper backing at some point getting real hot or maybe real humid and sticking to the film, or, two, your camera has a worn old fabric shutter curtain and it leaks, so light focused through the lens casts the fabric pattern on the film, Does the effect vary from frame to frame? I had an Exacta that did this, but with pin holes, not a pattern. The amount and density would vary. If I shot inside, nothing was apparent. If I shot outside, they would show, and the sunnier it was the worse the effect.
     
  5. gmikol

    gmikol Member

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    Another possibility...could this be the texture from the pressure plate? A pattern embossed by your print dryer? Or is this a neg scan?

    --Greg
     
  6. Ian Grant

    Ian Grant Subscriber

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    Probably moisture issues causing problems between the film & backing paper. It's important to let films warm up slowly, 24hrs or at least overnight from refrigeration and 3 days from frozen - Ilford stressed this on a factory tour a couple of years ago.

    There's moisture in the film and particularly the backing paper (even when foil sealed) and if the film goes from one extreme to another there's no time for the cold moisture to diffuse out.

    Ian
     
  7. labasarabas

    labasarabas Member

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    Hi, and thanks for all the replies.

    I doubt if it's to do with condensation from moving film from cold to hot. I'm careful about this, and have shot in much more extreme conditions without negative results (pun!) My film is stored in a tupaware type container in an Esky, which is cool, but not cold. The days on this trip were warm, but not hot. I don't leave my gear in the sun. A clue must be the evenness of the grid, it doesn't look organic.
    JBrunner, I had to look up SWAG! It was a Rolleiflex TLR with no cloth shutter so not a fabric photo-gram.
    gmikol, it's definitely not from the pressure plate, and what you see is a neg scan, not print scan.

    Since my first post, a friend suggested that it's reticulation during processing, exasperated by moire during the scanning. I use thermometers and tempering baths for the processing, but maybe the wash temp changed ?? It's on the whole roll, but I'll have to check tomorrow if it's even throughout. It's very even and grid like to be reticulation I woulda thought.

    I'll report again as soon as I've had a chance to re scan to see if it's moire. Any more suggestions welcome.

    -cheers
     
  8. jerry lebens

    jerry lebens Member

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    That really is weird. I doubt it's a reticulation/Moire effect, though. Reticulation is too irregular to cause such a regular 'interference' pattern. Does it only appear on the scans? Can you see it on the film using a loupe?

    To me, it looks like something (with a texture) has been pressed into the emulsion whilst it was wet.

    Regards
    Jerry
     
  9. labasarabas

    labasarabas Member

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    I agree Jerry. The only thing ever pressed against the film is the backing paper. I won't get a chance to put a loupe to the film 'til Sunday, and I'll rescan it at a slight angle to see if the lines change.

    mmmmmmmm
     
  10. Thomas Bertilsson

    Thomas Bertilsson Subscriber

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    I've had this happen on one single roll of TMax 100. It shows up in a scan, and it similarly shows up in a print.
    It was film that was given to me, and it was about a year out of date with no guarantee of how it had been stored.
    I have a feeling it had been frozen and the plastic wrapper was leaking, causing a moisture problem while defrosting.

    I will never use outdated film again, only fresh, and I don't freeze my film anymore. I just buy enough to get me by within the guaranteed period of the film, keeping it at room temperature.

    - Thomas
     
  11. polyglot

    polyglot Member

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    Not the pattern I had, oh well. Interesting texture though...