Blue color cast in Plus-X Pan Film

Discussion in 'B&W: Film, Paper, Chemistry' started by sanking, Nov 2, 2005.

  1. sanking

    sanking Member

    Messages:
    4,813
    Joined:
    Mar 26, 2003
    Location:
    Greenville,
    Shooter:
    Large Format
    Some while back I acquired a fairly large supply of Plus-X Pan film in 220 size. The film is outdated by several years but the B+F is still fairly low. However, there is a very pronounced blue color cast to the film after developing, even with long washing. I have never seen this particular color cast. Is is something I could/should remove? If it can be removed, what is the techique?

    Sandy
     
  2. jim appleyard

    jim appleyard Member

    Messages:
    2,131
    Joined:
    Nov 21, 2004
    Shooter:
    Multi Format
    Hi Sandy, I had this problem a few years back and called Kodak. It's either the anti-halation backing or the sensitizing dyes, I don't remember which. Their answer was to fix longer; not really a great answer as I had already fixed it long enough and longer fixing times are not really a great thing to do.

    I have a pet peeve about the blue and purple stains on Kodak's b/w films, which is why I don't use them much. I realize they don't cause any harm, but it makes me "feel" like the film is underfixed and/or underwashed.

    I did cure the problem by doing a pre-soak for 5 min. with 1/2 teaspoon of sodium carb/liter of water. That got rid of most of the blues.

    Another cure is to soup the film in Rodinal. I think the higher ph helps get rid of the color.

    Hope this helps, J

    BTW, my Plus-x was new.
     
  3. Rlibersky

    Rlibersky Subscriber

    Messages:
    783
    Joined:
    Apr 6, 2005
    Location:
    St Paul MN
    Shooter:
    8x10 Format
    Presoaking will take care of most of it. But if you can deal with the color, it doesn't seem to cause any problems. If you decide you can't deal with the color I wouldn't mind an oppyrtunity to get some 220 Plus-x
     
  4. sanking

    sanking Member

    Messages:
    4,813
    Joined:
    Mar 26, 2003
    Location:
    Greenville,
    Shooter:
    Large Format

    I am trying the sodium carbonate fix now. BTW, I developed this film in Pyrocat-HD, which has a working pH of around 10.9. Is the working pH of Rodinal higher than 10.9?

    Sandy
     
  5. gainer

    gainer Subscriber

    Messages:
    3,725
    Joined:
    Sep 20, 2002
    I noticed that blue cast in my first experiments with PX in sulfite-free ascorbate developers. These were of fairly high pH, though I didn't measure pH. If sulfite is the cure, I would think hypo clearing agent would do it. At the time, I thought it was the color of the base, so didn't try to cure it.
     
  6. sanking

    sanking Member

    Messages:
    4,813
    Joined:
    Mar 26, 2003
    Location:
    Greenville,
    Shooter:
    Large Format
    I post-soaked the film in a 5% sodium carbonate solution for 15 minutes, and the blue cast remained. I then treated it in a 5% sodium sulphite solution for 30 minutes and it cleared.

    Wonder how much pre-market research the good folks at EK did on these annoying magenta and blue dyes that are so difficult to remove before introducing them on the market? Now, if the dyes added some magical quality to the performance of the negatives I could understand the hassle, but that does not appear to be the case.

    In any event, I have been able to remove both the magenta and blue color cast with a prolonged soaking in 5% sodium sulphite. But it is very annoying to have to do it.

    Sandy
     
    Last edited by a moderator: Nov 2, 2005
  7. jim appleyard

    jim appleyard Member

    Messages:
    2,131
    Joined:
    Nov 21, 2004
    Shooter:
    Multi Format

    I have no idea what the ph of a w/s of Rodinal is. I had always made the assumption that is was fairly high due to the sod./pot. hydroxide. I am also making another assumption that the high ph removes the blues. Just a guess...I'm an Evil Scientist, not a real one! :smile:
     
  8. jim appleyard

    jim appleyard Member

    Messages:
    2,131
    Joined:
    Nov 21, 2004
    Shooter:
    Multi Format

    The color casts are why I don't shoot more EK b/w film. Fine films, good images, but it's an aesthetics thing. Yes, I would think it would be annoying to have to soak my film for an extra 30 min!
     
  9. fschifano

    fschifano Member

    Messages:
    3,216
    Joined:
    May 12, 2003
    Location:
    Valley Strea
    Shooter:
    Multi Format
    You've done nothing wrong. A blue tint to the base of Plus-X film is normal. Same thing goes for the slight magenta cast to Tri-X. Unlike the TMX and TMY films, these do not wash out and appear to be a permanent coloring added to the film support.I don't know why it's there, I'm not a film engineer. All I do know is that these films are capable of producing first rate images. Honestly, I don't understand why some people find it annoying. I don't care what color tint the base has as long as it prints well. For me, the negative is a means to an end, namely the print.
     
  10. sanking

    sanking Member

    Messages:
    4,813
    Joined:
    Mar 26, 2003
    Location:
    Greenville,
    Shooter:
    Large Format
    I don't see the blue and magenta color cast as normal but as anti-halation dye that is very difficult to clear. And, although it may be possible to make good prints from negatives that have a strong blue or magenta cast I strongly suspect that such negatives will have different printing characteristics with VC papers and UV sensitive processes than negatives that are neutral in tone, and probably also in scanning if done in RGB.

    Sandy
     
    Last edited by a moderator: Nov 3, 2005
  11. Mark Layne

    Mark Layne Member

    Messages:
    919
    Joined:
    Jun 9, 2003
    Location:
    Nova Scotia
    Sandy
    I have used Plus -X off and on for 40 years and it has always had that blue cast. I am told that when production was moved to the new coating machine the cast disappeared.
    I also found Plus-X a little more blue sensitive than usual, benefitting from a yellow filter.
    There is also a larger than usual reduction in graininess when exposed at 64 ASA vs 125

    Mark
     
  12. Donald Qualls

    Donald Qualls Member

    Messages:
    1,845
    Joined:
    Jan 19, 2005
    Location:
    North Caroli
    Shooter:
    Multi Format
    If you're not already doing so, you might find the color reduced by using HCA after fixing. I've found a soak in 2% sodium sulfite solution with 1 tsp per quart of sodium carbonate added (essentially homemade HCA) quickly decolors the dyes that sometimes remain in films I've developed in tubes, where the backing of the film was in contact with the tube surface. A two minute soak in the improvised HCA clears them right up.
     
  13. jim appleyard

    jim appleyard Member

    Messages:
    2,131
    Joined:
    Nov 21, 2004
    Shooter:
    Multi Format

    Odd, but I've found just the opposite to be true. The base color of my Plus-x negs from years ago is clear or slightly gray, but the new Plus-X that I've shot is blue.

    Hmmmm????