Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 71,808   Posts: 1,581,502   Online: 1076
      
Page 1 of 2 12 LastLast
Results 1 to 10 of 13
  1. #1
    Greg Davis's Avatar
    Join Date
    Feb 2004
    Location
    Crestview Hills, KY
    Shooter
    8x10 Format
    Posts
    1,950

    RA-4 Starter and temperature tests

    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
    Attached Thumbnails Attached Thumbnails RA-4 Control Strip 01.jpg   Y-55 RA-4.jpg   RA-4 Control Strip 02.jpg   RA-4 Control Strip 03.jpg   RA-4 Control Strip 04.jpg  

    RA-4 Control Strip 05.jpg   RA-4 Control Strip 06.jpg   RA-4 Control Strip 07.jpg  
    www.gregorytdavis.com

    Did millions of people suddenly disappear? This may have an answer.

    "No one knows that day or hour, not even the angels in heaven, nor the Son, but only the Father." -Matthew 24:36

  2. #2
    Mike Wilde's Avatar
    Join Date
    Aug 2006
    Location
    Misissauaga Canada
    Shooter
    Multi Format
    Posts
    2,939
    Images
    29
    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.
    my real name, imagine that.

  3. #3
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,518
    Images
    65
    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. #4
    Greg Davis's Avatar
    Join Date
    Feb 2004
    Location
    Crestview Hills, KY
    Shooter
    8x10 Format
    Posts
    1,950
    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.
    www.gregorytdavis.com

    Did millions of people suddenly disappear? This may have an answer.

    "No one knows that day or hour, not even the angels in heaven, nor the Son, but only the Father." -Matthew 24:36

  5. #5
    Greg Davis's Avatar
    Join Date
    Feb 2004
    Location
    Crestview Hills, KY
    Shooter
    8x10 Format
    Posts
    1,950
    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.
    www.gregorytdavis.com

    Did millions of people suddenly disappear? This may have an answer.

    "No one knows that day or hour, not even the angels in heaven, nor the Son, but only the Father." -Matthew 24:36

  6. #6
    brucemuir's Avatar
    Join Date
    Dec 2007
    Location
    Metro DC area, USA
    Shooter
    Multi Format
    Posts
    2,264
    Images
    4
    Quote Originally Posted by Greg Davis View Post
    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.
    In what way? Can you elaborate.
    Uneven color or density or an overall cast?

    Thanks Greg.

  7. #7

    Join Date
    Jul 2011
    Shooter
    8x10 Format
    Posts
    2,792
    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. #8
    Greg Davis's Avatar
    Join Date
    Feb 2004
    Location
    Crestview Hills, KY
    Shooter
    8x10 Format
    Posts
    1,950
    Quote Originally Posted by brucemuir View Post
    In what way? Can you elaborate.
    Uneven color or density or an overall cast?

    Thanks Greg.
    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.
    www.gregorytdavis.com

    Did millions of people suddenly disappear? This may have an answer.

    "No one knows that day or hour, not even the angels in heaven, nor the Son, but only the Father." -Matthew 24:36

  9. #9
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,518
    Images
    65
    Yep, prewet, prewet, prewet! Nothing can be finer for good results!

    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. #10
    hrst's Avatar
    Join Date
    May 2007
    Location
    Finland
    Shooter
    Multi Format
    Posts
    1,300
    Images
    1
    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.

Page 1 of 2 12 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin