Problems processing sheet film in drum

Discussion in 'Large Format' started by david_nebenzahl, Sep 4, 2003.

  1. In a previous posting I crowed about my clever way of processing 9x12 film in a Beseler Unidrum for 8x10. Well, now I guess I have to eat a little of that crow.
    The last batch of film I processed was a single piece of Efke 100, and while the film was processed well, I had a problem with the back side of the film. There was a streak of the (I'm guessing) anti-halation coating on the back where the film was stuck against the side of the drum. This was not a fatal problem; a short rinse in plain water removed the remnants of the coating.
    This is an annoying problem, though, and one just as likely to occur with other sizes of film in the drum, since there's nothing to keep the back surface of the film from sticking to the sides.
    Should I just learn to live with this problem? I suppose I could incorporate a post-rinse into my processing, using trays. At least I wouldn't be shuffling sheets in the tray in the dark, which is pretty much the whole reason for using the drum in the first place. Or is there another trick one can use here?
     
  2. I've never used a Beseler drum, but the unicolor drums ar ribbed inside to keep the film from touching the walls.
     
  3. Since you're clearly very good at rigging things up, maybe try putting some more spacers in the drum to hold the film away from the edge (which is what I've always assumed the V rib was for when processing 8x10 - at least that's how I've been using it, and I've gotten good results).
     
  4. You can cut some fiber glass screen the size of the negative. Place it behind the film and then insert the film/screen into the drum. It is thick enough to separate the film from the side of the drum.
     
  5. My solution was a trip to the Plastruct stand at the hobby shop. Plastruct is the brand name for all sorts of styrene and ABS plastic shapes used for building models. Small strip about 1/8 inch wide in either a triangle or L shape work well. Cut some lengths an inch or two long and glue inside the drum. This keeps the film off the drum and using the short random lengths still allows developer to flow behind the film.

    In the end I gave up on the drums because of the inconsistent development I was getting.
     
  6. JOBO had some spacers for film processing in paper drums. I don'T know how to substitute it yet.
    Maybe some net material?
     
  7. Use a Jobo 3010 Expert Drum. Yes they are somewhat expensive initially, but you will soon find out why they are worth the money. I get totally even development with the 4 various Expert Drums I have, and they are very easy to load.
     
  8. David,

    Try a Unicolor drum for paper. I've been using them for about a year. Hook up your darkroom timer for results so consistent its about as exciting watching dust bunnies grow under the bed!--Cheers!
     
  9. I've used the Unicolor drums for paper and had the same problem. I soaked them in a tray of fixer a minute or two when they came out of the drum to clear them.

    I found the film was difficult to get a hold of when stuck to the side of the drum with solution. I plan on putting the plastic ridges described by David in mine and solving both problems. The Jobo and a couple other manufacturers have ribs built inside already.

    I like the Beseler over other drums because it has the smallest lip catching the film. That translates to the least turbulence and very even development. For 5x7 I use the 11x14 paper drums that let me process four sheets at a time. Using an enlarger timer on the motor guarantees identical processing from batch to batch. If a negative has a problem, I'm confident it wasn't the developing process because I have three other negs to compare it to. I play a lot of games with light and exposure (I'm learning the ins and outs of painting with light right now). The drum processing gives me more confidence in the film processing and improves my confidence in the results of exposure experiments.
     
  10. I use the Beseler drum. The problem as I encountered it was inconsistent insufficient
    fixing on some parts of the neg that were in contact with the drum. My solution was
    to pull the negs out of the drum about half way through the fix and finish the fix in a
    tray (and in the light). They were going to come out anyway for the wash, so this
    doesn't really add any work. The 25 or so 4x5's I've done this way look just fine.
     
  11. I use a 8x10 drum made by western. I have the same drum make with another name on it. These can be had new for $10.

    They have ridges all around the tank which keeps the flim away from the back and I don't have any problems. They work much better then the run of the mill paper tanks...

    jay...
     
  12. Just to clear up any residual confusion here, the drum I'm using is the Beseler paper drum, not the film drum. (The film drum isn't as useful for sheet film, oddly enough.) The paper drum has no ridges, just the one strip in the middle.
    The last sheet I developed was fine, by the way. I think I'm gonna elect to just live with this occasional problem, and invest in some small trays for when I need to do a post-soak to remove any leftover coating.
     
  13. I'm not familiar with this drum. Do you remove the film from the drum before fixing (i.e. do you fix in trays as is done with the BTZS tubes)? If you remove the film from the drum after the stop bath and then fix it in a tray the dye will come off in the fix without doing anything special.
     
  14. To answer your question, you could take the film out to fix it in a tray; I don't. Actually, as I indicated above, the problem I reported doesn't always happen; the last batch I did was fine.
    Actually, I find the hardest part of using this drum to be getting the film out when done, especially the two sheets way at the bottom of the thing. Now if I had some kind of special hook ...
     
  15. Guys, the _Beseler_ brand paper drum has no ridges and the film will stick to the sides. The only solution is to remove it, rinse etc.

    The _Unicolor_ brand paper drum has small ridges all around the inside surface. Film won't stick to the sides and the back coating is decolorized normally etc.
     
  16. Had the same problem.....SOLUTION= DRY TANK BEFORE USE. I pre warm tank with a hair dryer to insure tank is dry....Now no problem.
     

Share This Page

1111