Neopan 400 reticulation?

Discussion in 'Black and White' started by goemon, Feb 18, 2005.

  1. I've been having a problem recently with Neopan 400 in 120. I tend to
    shoot it, pop it into Ziplock bags, put it in my freezer, and then let
    it thaw before processing. I process it in XTOL 1:1, not that that
    should matter much.

    The problem is, after developing, I look at the images with a 10x
    loupe and see some strange patterns in the emulsion that look kinda
    like a mosaic. I initially thought "perhaps I am not letting it thaw
    long enough?" and let one roll thaw for something like twelve hours,
    processed entirely at room temperature using room temperature
    chemicals and with distilled wash water. No trouble. I tried again,
    long thaw, room temperature chemicals, tap water (which in my area is
    very hard) at something close to room temperature, Photoflo, let hang,
    again no problem. Yesterday I let some of the stuff thaw for four
    hours and had the problem again.

    So my questions are: a) is this pattern characteristic of
    reticulation? b) is four hours really not enough to thaw this film in
    120? c) am I doing something dumb? I have not had this problem with
    any other film--FP4+, Delta 400, TMX, Acros. I'd test it in 35mm, but
    I don't have any and my usual dealer has been out of stock in 35mm for
    a while.

    Alternatively I suppose it's possible that I got a batch of the stuff
    that's bad, but I'd like to ask the forum whether I'm barking up the
    wrong tree with this before I start developing entirely unshot rolls
    to see if there's a coating problem.
     
  2. Newly bought film, placed in the freezer, has a moisture level deemed safe by the maker - likely so low the mechanics of freezing are moot. When you freeze an opened roll you introduce an unknown level of moisture to the gel which, after freezing, has every right to look like your windshield on an icy morning. That you get away with sometimes is irrelevant.
     
  3. Four hours should be plenty of time for the core of the roll to come up to room temperature -- I can thaw a pound of hamburger on the counter in that time. However, it's possible the gelatin continues to change state for a considerable time even after the temperature stabilizes, and that, if anything, would be the prime candidate for what you're seeing in rolls that haven't been out of the freezer long enough.

    Simple solution: don't freeze your exposed film. It won't hurt it a bit to sit at room temperature for a few days, or even for a few weeks, before you process it. I recently had processed a roll of Kodak Max 400 (consumer color film) that had been in my Spotmatic for more than four months, including storage inside a loaded vehicle parked in partial sun for three weeks in late summer and several more weeks of hot weather before the onset of autumn -- and it was perfect.

    I do freeze my film for long term storage (more than a couple months) prior to exposure, but I give it days to thaw, and then don't refreeze after exposure (typically no more than a couple weeks from exposure to processing). I do, however, freeze 35 mm that was bulk loaded, and haven't seen any of the problem you describe with my very long thaw in the sealed bag.
     
  4. The main reason I started freezing it in the first place was I got called out of town and away from my darkroom for an extended period of time (many weeks); while I was out of town I shot a great deal of film and couldn't develop any of it. Insofar as this is likely to happen again in the summer, I'm somewhat concerned; I don't want the latent image to go away, but I don't want this mosaic crap either. I'll hold off on the newer stuff, at least.
     
  5. I remember a thread in this forum maybe a year or two ago about high speed bw-film / pushed medium speed films where Lex wrote a long column about loss of shadow detail in undeveloped film within a month worth of about one zone compared to immediately developed films.<br>While he was refering to film speed of ASA 1600 and + you should not face any problems with fading images within a couple of weeks with Neopan 400 exposed at 400 or lower. I had some left in my camera up to almost half a year prior finishing the roll and developing without problems.
     
  6. Aki remembers correctly. I noted a significant loss of shadow detail (what little there was) in a roll of TMY pushed to 1600 in which there was a month's delay between exposing the beginning and end of the roll before processing. Pushed film needs to be processed immediately. If I must delay I'll freeze the exposed roll.

    At the other extreme I exposed half a roll of Provia 100F normally, then left the camera in a drawer for a year. After I finished the roll I had it processed immediately. I couldn't see any difference between the beginning and end of the roll.
     
  7. I've only had it to happen on one roll, it was a 120 roll and a good 25 years ago. I always thought it was that there was a variation in temparture of processing solutions,or maybe in the wash water temparture....Jim
     

Share This Page