RA-4 developer affect archival qualities?

Discussion in 'Color: Film, Paper, and Chemistry' started by Stew, Dec 26, 2006.

  1. Stew

    Stew Member

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  2. Photo Engineer

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    There is nothing in the formula that will affect dye stability, but the formula is not correct for optimum results.

    PE
     
  3. Shinnya

    Shinnya Advertiser Advertiser

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    Great!

    Does this really work? Should I just buy the premixed kit?

    Warmly,
    Tsuyoshi



     
  4. Shinnya

    Shinnya Advertiser Advertiser

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    Ron,

    Do you have one or redirect me to another source?

    Thanks.

    Warmly,
    Tsuyoshi



     
  5. Photo Engineer

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    Tsuyoshi;

    I cannot post the actual formula.

    However, there is a redirection on Photo Net with a URL that has a very good web site with a much better formula. The real formula has a precise pH to allow for the perfect matching of reactivity of the 3 couplers with the developing agent and sulfite. All of these are critical as are other salts not listed. They are used to trim sensitometric curves.

    PE
     
  6. srs5694

    srs5694 Member

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    I've used the referenced formula and commercial RA-4 developers from various manufacturers. For the most part, the referenced formula does work (it develops exposed paper) and it produces colors that I find satisfactory; however:

    • I've not done careful side-by-side testing of this formula with any commercial chemistry. It's possible that there'd be visible differences in a side-by-side comparison.
    • My own skill as a color printer is limited, but improving. At the moment, I can match or exceed the quality of an average commercial print if I put in the effort, but if I just want to quickly crank out some small prints, the results are more hit-or-miss. When my skill level gets sufficiently high, I might conceivably start encountering limitations of the referenced formula.
    • I have run into one problem with this formula with some Konica RA-4 paper I bought cheaply on eBay: Unexposed parts of prints (such as borders or very light areas) come out slightly yellow, but they're white when I develop this paper with other developers. I don't know if this is a problem with this paper in this developer generally or if it's just a question of the paper being old enough that it's gone a bit "off" and this developer highlights the problem. I've not had this problem with Kodak, Fuji, or Agfa paper that I've bought new.

    FWIW, I've always mixed the developer using distilled water.

    I do know of another Web-accessible developer formula for RA-4 paper: http://www.people.fas.harvard.edu/~keirst/technical.html. I've never used this formula because it's requires several ingredients that I don't have and that don't seem to be carried by the usual raw photochemistry suppliers. (I'm sure I could track them down, but I've not bothered to do so yet.) I have no idea if this is the same formula to which PE refers indirectly.
     
  7. Photo Engineer

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    Yes, this is the same formula and is more closely aligned with the actual RA developer formula. It will work much better than the other formula.

    I would like to add that the pH is critical in a color developer to get matched dye curves. This developer should be about 10.1 at 20 deg C, IIRC.

    PE