developing 8x10

Discussion in 'Black and White' started by christopher_ward|2, Jul 3, 2020.

  1. Looking for a better developer for the constant agitation of a print drum/tube for my 8x10 sheet film.
    Usually use HC-110, T-Max or Rodinol with time reduction compensation to keep over development in check.
    Any thought about a better developer for this style of processing?
    8x10 Cibachrome drum, standard single speed motor base with 6 oz. developer as single shot.
     
  2. AJG

    AJG

    I've processed thousands of sheets of 4x5 in a Jobo tank with reels on a Unicolor roller. When I first got it I had major streaking problems with my standard HC 110 dilution B, so I called the company and their tech told me that what I needed was a different dilution that resulted in a 10 minute developing time at 68 degrees F. It took some testing to come up with the right dilution but it did solve the problem of streaks completely. The Unicolor roller switches direction every 3 seconds or so, and the other piece of advice from Jobo was to stop the roller once a minute and pick up the tank and agitate it like a regular stainless steel roll film tank for 5 seconds. 5000+ sheets later the problem was solved by these steps. Good luck!
     
  3. OK , manual agitation should help for streaks and more dilute developer for contrast build up. Dose anyone know if the unicolor or cibachrome roller bases can be used with a dimmer switch?
     
  4. AJG

    AJG

    I can't answer your dimmer question, but the point of the longer developing time/more dilute developer was to create a longer processing time to minimize streaks, not change contrast.
     
  5. Dilution normally does change contrast at least a small amount.

    One of the phenomena that controls development is "local exhaustion" of the developer around higher density areas. Brownian motion of the water/developer molecules counteracts this somewhat(and will also be more pronounced at higher temperatures) but when using intermittent agitation it happens until you agitate to bring fresh developer to the film.

    More dilute developers will have this happen more quickly, somewhat reducing contrast. Reduced agitation can also lower contrast.

    If you're doing continuous agitation via rotary processing or whatever else, of course, this is all a moot point.
     
  6. What exactly is wrong with the 3 developers you've already tried?

    Give us a clue as to what parameter you're trying to change. Contrast, tonal separation, shadow detail.... what? The issue might not lie with the developer at all.

    Both HC-110 and Rodinal should give you great flexibility in terms of processing time by changing their dilution. Although Rodinal is never going to give you the finest grain, nor the best tonality.

    Dimmer switches usually use phase-angle triggering of a Triac, and as such they should work with simple induction motors. However, the power of the motor will be reduced along with its speed. Therefore there's a risk of stalling the motor, or of inconsistent speed if you try to lower the speed too far.
     
  7. I am getting dense somewhat uneven development across the sheet. I know with roll film to much agitation can lead to over development and shadows blocking up.
    I remember some developers made for machine processing in the past but do not know if they still exist. I have reduced the ISO film speed 1/3 f/stop to compensate for over agitation. I have been thinking about trying the two part developers to get more consistent results.
     
  8. It sounds as if the developing technique is at fault, and not the developer.

    I found that using 5x4 B&W film in a Jobo CPE-2 machine needed a pre-bath to get rid of filling and foaming marks. Although, strangely, C-41 colour processing works better without a pre-bath.
    Huh? Shadows blocking up? There's no way that overdevelopment will cause that. Unless you mean increased highlight density on the negative.

    Any overdevelopment should be easily solved by reducing the development time or increasing the dilution. But a plain water pre-bath will effectively increase the developer dilution anyway.

    You're probably using large diameter drums with the film stuck to the inside walls to develop 10x8. Remember that the peripheral speed of the drum is going to increase with its diameter, and the RPM will need to be reduced accordingly.
     
    Last edited: Jul 5, 2020
  9. Dimmer switch is wrong for any motor.

    There are controllers electrically close to dimmers that will work for the usual series-wound
    motor for electric drills and such.

    But Uniroller is more likely an induction motor, which works on line frequency and
    not voltage, so the usual controller won't help.
     

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