Page 2 of 2 FirstFirst 12
Results 11 to 19 of 19

Thread: Identifying film coating faults vs. handling / process problems.

  1. #11

    Join Date
    Oct 2017
    Posts
    409

    Re: Identifying film coating faults vs. handling / process problems.

    PS: I’m using PMK in the Jobo with the Bergger Roto Additive. Water stop and rinse. Ilford Hypam fix. Water is filtered to extremely fine grade. Rinse is in filtered water.

    My guess for banding is that it would be extremely unlikely to be the drum I’m using as the bands seem the same on all sheets - if I lined them up they’d continue through at exact spacing and height. They’re very faint, but visible if I print dark.

  2. #12

    Join Date
    Jul 2016
    Posts
    4,566

    Re: Identifying film coating faults vs. handling / process problems.

    Quote Originally Posted by Tim V View Post
    I purposely didn’t name the manufacturer because I want to know what I’m seeing first on my negatives before pointing the finger.
    You don't point the finger. You say you have a problem with a particular film/processing, if you provide data (the crops) others may help you if they had the same.


    Quote Originally Posted by Tim V View Post
    Any resources to reference?
    This pdf is about pitfalls in processing, not in emulsion defects, it's about technical imaging (NDT), but it solved me some problems I had:

    ndt-ImageGuide-201403.pdf

    search that doc with google

  3. #13

    Join Date
    Oct 2017
    Posts
    409

    Re: Identifying film coating faults vs. handling / process problems.

    Thanks Pere, I'll check it out!

    I'll post some crops when back at the studio, hopefully tomorrow.

  4. #14

    Join Date
    Nov 1999
    Location
    San Clemente, California
    Posts
    3,804

    Re: Identifying film coating faults vs. handling / process problems.

    Quote Originally Posted by Tim V View Post
    ...Any resources to reference? I’ll post samples soon...
    Ask your question and post those samples at PHOTRIO. Direct them specifically to Ron Mowery ("Photo Engineer"). He's retired from Kodak Research Lab, spent many years working on coating of various films and will provide authoritative information when answering. He's done so before.

  5. #15

    Join Date
    Oct 2017
    Posts
    409

    Re: Identifying film coating faults vs. handling / process problems.

    After analysis of the scans and negatives under the loop I can say that it’s simply badly scratched emulation, but not due in any way to processing or my handling - I’m simply far too careful and in a great quantity of other brand film processed in exactly the same way I’ve never seen scratches like this before - maybe the odd scratch, but I’m talking quite intense, localised areas of scratching in many areas of same negative. Too bad, I like the tonality if the film.

    Like many others have already said, perhaps my experiment simply tells me that it’s not worth straying from “the big two”...

  6. #16

    Join Date
    Jul 2016
    Posts
    4,566

    Re: Identifying film coating faults vs. handling / process problems.

    Quote Originally Posted by Tim V View Post
    but not due in any way to processing or my handling - I’m simply far too careful and in a great quantity of other brand film processed in exactly the same way I’ve never seen scratches like this before
    You cannot be sure about that... Perhaps your processing has been careful enough for (say) TMX/D100, but for example if your fim is (perhaps rebranded) beautiful Shanghai GP3 then you may consider using a hardener and you should not touch the emulsion when wet, using Film Squeeze may destroy some (old tech) films. I've not used GP3 recently, but it was really easy to scratch.

    I never had a problem with ilford/kodak but for GP3 I had to change my procedures, it consisted in using a final distilled water rinse to not have to squeeze much the film.

    ...so you may do that, don't squeeze a test sheet, if scratches disapear then buy some Double-Distilled (bidistilled) water and make a final rinse with it, you may reuse the bidistilled bath, but in that case do it like with double fixing bath, have separated first and a second baths, and after some 30 reuses dump the first bath use the second bath as first bath, and refill the second bath with bidistilled. If using photoflo then use only a fraction of the normal dose.

    Reusage of Bidistilled may be cost effective, because it's more expensive.

  7. #17

    Join Date
    Oct 2017
    Posts
    409

    Re: Identifying film coating faults vs. handling / process problems.

    Apologies, I forgot to say I inspected an unexposed sheet in the light. I could see subtle marks on it.

    I guess I was just really hoping it was a handling fault because the film is really nice, save for these issues which apart from the subtle banding seem random but frequent enough to be too risky in my book.

    I’m not keen on naming the manufacturer as it’s possible I’ve simply been unlucky and in any event I’ll raise it with them directly - in my experience that is a more positive way to do it and will more likely lead to product improvement.

  8. #18

    Join Date
    Sep 1998
    Location
    Loganville , GA
    Posts
    14,409

    Re: Identifying film coating faults vs. handling / process problems.

    Quote Originally Posted by Tim V View Post
    Apologies, I forgot to say I inspected an unexposed sheet in the light. I could see subtle marks on it.

    I guess I was just really hoping it was a handling fault because the film is really nice, save for these issues which apart from the subtle banding seem random but frequent enough to be too risky in my book.

    I’m not keen on naming the manufacturer as it’s possible I’ve simply been unlucky and in any event I’ll raise it with them directly - in my experience that is a more positive way to do it and will more likely lead to product improvement.
    No, what you are really saying is that if it is a film problem, you will let unsuspecting browsers here run into the same problem since they won’t know what you found!

  9. #19
    jp's Avatar
    Join Date
    May 2009
    Location
    Maine
    Posts
    5,628

    Re: Identifying film coating faults vs. handling / process problems.

    PMK can streak under some conditions, so that sky/highlight unevenness could be tested with another developer. But if you're finding damage to the film prior to it going into film holders, time to stop using it.

Similar Threads

  1. Handling xray film
    By joem in forum Darkroom: Film, Processing & Printing
    Replies: 7
    Last Post: 27-Aug-2019, 06:15
  2. Help Identifying Problem in C-41 Process Run
    By dpn in forum Darkroom: Film, Processing & Printing
    Replies: 6
    Last Post: 25-Nov-2016, 17:26
  3. Paper Coating Problems
    By William Marderness in forum Darkroom: Film, Processing & Printing
    Replies: 2
    Last Post: 23-Mar-2002, 09:09
  4. Film developing faults on the Web
    By James Phillips in forum Darkroom: Film, Processing & Printing
    Replies: 2
    Last Post: 27-Sep-2000, 21:10

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •