RA-4 Starter and temperature tests

Discussion in 'Color: Film, Paper, and Chemistry' started by Greg Davis, May 8, 2012.

  1. Greg Davis

    Greg Davis Member

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    While running a different test of materials, I concurrently ran a test of RA-4 control strips at varying temperatures as published by Kodak in the Color Darkroom Dataguide. While running these tests I noticed my strips coming out too red, I called Kodak and discussed it with them and they suggested I try adding the Starter for RA-4 RT Developer/Replenisher. I have never used it with my RA-4 before, but I had also never ran control strips before, so I thought I would try it and see. I immediately noticed a difference and an elimination of the red cast. I also tried using the RA-4 RT at 75° F (23.8°C) to see if it would work. I found it to be too weak in the D-max, but I only used a 2 minute development time. When time permits, I may try it again for 3 minutes to see if it plots better. I am including a Y-55 chart of each temperature with and without the starter. Each column represents one combination of variables. The Alt. Process column at the end refers to the other test I was performing.

    The temperatures and times tested were:

    75° F (23.8°C) for 2 minutes
    83° F (28.3° C) for 2 minutes
    88° F (31.1°C) for 1.5 minutes
    94° F (34.4° C) for 1 minute
     

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  2. Mike Wilde

    Mike Wilde Member

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    I have never had the urge to get that analytical about the process yet. I guess I am luck to have a good little CP-31 roller processor that runs at 38 and 45" per tank consistently. I feed my RA-RT the specified volume of starter to make up a working solution, but my starter is labeled as being made under a Champion brand(who I think actuially makes the Kodak usa photochemicals now).

    So where did you come by control strips to fiddle with; I have looked in the apst,a nd the price put me off.
     
  3. Photo Engineer

    Photo Engineer Subscriber

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    Greg;

    From other posts here and other samples sent to me by people trying this out, I can say that Fuji CA is not as amenable to processing at lower temps as is Endura. In addition, a small exposure change and color balance shift has been sufficient (in my hands) to adjust for this type of variation. IDK if the same is true of Fuji CA as the emulsions differ substantially from those in the Endura.

    PE
     
  4. Greg Davis

    Greg Davis Member

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    I don't disagree. I was just in mood to try stuff out and see what happens. I agree that Fuji acts differently than Kodak paper, but I don't have any Kodak left in sheets, so testing out the Fuji was pertinent to my darkroom. Kodak materials may not show the red color when starter is omitted, but Fuji did. I have made prints without starter and filtered it out just fine. But the cooler processing turned out just fine if I followed Kodak's time and temperature combinations. I noticed a lower contrast when I dipped cooler than 83 degrees, but I may be able to compensate with a longer development time. If not, and I still want results I know would pass a control strip, I can easily process at 83 degrees in my drums. A lot of this is to show students in our color darkroom courses, and may be important when our Kreonite finally dies.
     
  5. Greg Davis

    Greg Davis Member

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    I should note that I also got very poor results if I did not use a prewet in the drums. I was surprised by that result.
     
  6. brucemuir

    brucemuir Member

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    In what way? Can you elaborate.
    Uneven color or density or an overall cast?

    Thanks Greg.
     
  7. DREW WILEY

    DREW WILEY Member

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    CA papers and RA/RT starter work wonderfully together. I prefer to use 2 min times because it is short enough to minimize temp reduction in the drum, but long enough to realistically factor in the fill and drain times. I always use a tempered prewet with an excess volume of water, which helps get
    the internal temp of the drum correct. I don't have my specs here, but I think it's 82F. I also mix my
    concentrates for each work session, and use them strictly one-shot.
     
  8. Greg Davis

    Greg Davis Member

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    Low density and a slight color shift. I assume it is from an immediate lowering of the temperature during development when skipping the tempering effect of the prewet. With drum processing I found no need for a stop bath and rinse between developer and blix as I have with trays or a Nova processor.
     
  9. Photo Engineer

    Photo Engineer Subscriber

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    Yep, prewet, prewet, prewet! Nothing can be finer for good results! :smile:

    As for any paper at any temp with RA-RT or RA-RT + Starter, the results may vary by a small bit, but with a bit of adjustment you fix up the problem. When I process at 100F (1' RA-RT, no starter) I use one filter pack and exposure setup. At 68 f I use about 10Y more and a very slightly different exposure setup.

    It has been no big deal to me. Barely nothing at all. However, some have complained about the ca papers. That is all. I cannot verify as I don''t use CA paper. You know, I am still an EK person despite what is being done to the company and name.

    PE
     
  10. hrst

    hrst Member

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    Definitely no problem with Fuji CA on room temperature without starter for me;

    Switching between Fuji CA and Kodak Supra Endura, I have to adjust filtration about 4M 4Y or so, with constant exposure; then the prints match quite well. (I have different sizes of CA and Endura, so sometimes I have to switch between papers.) So, the difference is very small. It MAY be that CA has a little bit higher saturation, especially at blue-green region, and Endura has a tad more "portrait" feel to it, but I'm not sure at all if this is true or just psychological.

    I also had read those report or two on some problems here on APUG. My guess is it was some other version of the paper. Rumors say there are many versions of Fuji CA with the same name. I haven't been too interested as the one I have works just fine and is VERY close to Kodak in everything except reversal processing, where it is no better nor worse, but needs a bit different first developer.
     
  11. Greg Davis

    Greg Davis Member

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    I didn't encounter any problem that couldn't be fixed by changing the filter pack or developing longer, I was just surprised at the difference when I first did a control strip withou a starter. I wasn't expecting that result since the prints never showed a problem. But then, you can't change the filter pack on a control strip.
     
  12. Photo Engineer

    Photo Engineer Subscriber

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    There are confirmed statements by Fuji that there are 2 or more versions of CA. That is all I can say now.

    PE
     
  13. RPC

    RPC Member

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    I recently tried some Fuji CA paper just to see how well it would work with Kodak RA/RT developer at room temperature, should I ever run out of my 500+ sheets of frozen Endura. My results were similar to hrst's, a minor adjustment in filtration was needed compared to Endura (about 15 Y and M), and a print of each laid side by side were almost identical. I could see no difference in a print developed for 45 seconds and one developed for two minutes. The Fuji seemed to have slightly higher contrast and saturation, but the big disappointment was in the shadow detail. Endura was superior.