Kodak RA-4/RT Process Changes

Discussion in 'Color: Film, Paper, and Chemistry' started by davetravis, Feb 14, 2013.

  1. davetravis

    davetravis Member

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    Hi all, been a while since I posted here.
    I'm printing my Ektar 100 negs onto FCA, using the Kodak RA-4/RT in an Ilford ICP42 3 tank roller transport processor.
    All is well and happy for the first 6 16x's. The chems were in the tanks for 7 days, kodak's suggested limit.
    So I dumped the DEV, mixed new and replaced it. Kept the BLX, and replenished with 500ml new.
    Here's the change.
    My next tests of the same neg, and same time/color filters settings,
    and using the new chems, were about 15% darker, and shifted about 5 to the Magenta side.
    I was able to correct for this and ended up with happy prints, but does anyone know why this happens?
    I'm thinking the time/color balance of the previous print, at the end of the chems life,
    is different than when I replaced with new DEV.
    Maybe something to do with stronger DEV action or something...
    Thanks.
     
  2. DREW WILEY

    DREW WILEY Member

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    I use RA/RT strictly one shot in drums, mixed per session, just so I don't have to worry about those kinds of variables. It is also quite important to keep the temperature well controlled. Maybe one of these days I work up the courage to test my own replenishable roller-transport machine.
     
  3. brucemuir

    brucemuir Member

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    same paper batch?
     
  4. Photo Engineer

    Photo Engineer Subscriber

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    That is 6, 16x20s? What is the tank capacity.

    My thought is that the blix is becoming exhausted and the pH is going up due to carryover of developer (unless you use a stop bath). With the pH rise, there is a chance of continued development and perhaps some silver or silver halide retention.

    Just a WAG based on what you see and without any knowledge of tank capacity of your system.

    PE
     
  5. davetravis

    davetravis Member

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    Hi PE,
    Yea 6 16x's went through, very close to the suggested square inches per volumne before replen.
    All tanks are 2 liters, with squeege rollers between. 95 degrees/45 secs per step.
    A 32ml. of Acetic Acid for 2 liters of H2O as stop.
    Using the same replen rate for the DEV and BLX/FIX.
    My rig doesn't have inline filters, so I print up to chem limits, within time-in-tanks limit, then either replen or dump/replace,
    depending on which comes first.
    The DEV time limit is 1 week, but the BLX time limit is 2 weeks.
    At this point the DEV time has expired, but the BLX/FIX still has another week.
    Deviations have always happened like this in the past, but I never really tried to understand why.
    Thanks.
     
  6. davetravis

    davetravis Member

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    Yea, same batch of paper, same size.
    Thanks.
     
  7. Photo Engineer

    Photo Engineer Subscriber

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    You are overstressing the Stop and the Blix. You probably have retained silver. You may have overdeveloped by the carryover of developer. After all, 6 16x20s is 4x6 = 24 8x10s and IIRC, they suggest not more than 25 8x10s in 4L (without replenishment) or have I got it wrong? That is way on the high side for all solutions. They are not bad, they are exhausted.

    PE
     
  8. davetravis

    davetravis Member

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    Yea that sounds right.
    I can normally get a little more productivity from the FCA, but not after 7 days in the tanks.
    Been smelling the fumes too long...
    Thanks.
     
  9. davetravis

    davetravis Member

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    Oh yea, one more:
    Kodak suggests a water bath after the stop, I only have 3 tanks, so not possible.
    Is there any effect on the BLX/FIX by not having the water bath?
    Thanks.
     
  10. Photo Engineer

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    I never have used one and have never had a problem. What it might do if there is too much carryover is lower the lifetime of the blix, and it might also lead to prints becoming reddish due to the pH being too low after the process. It is easy to check the pH with a meter and adjust it back up with household Ammonia from the grocery store. It should only take a few ml to do the trick.

    PE
     
  11. davetravis

    davetravis Member

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    Thanks!
    :smile: