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  1. #1
    RPC
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    RA-4 Home Brew and Endura Paper

    I have been testing an RA-4 home-brew formula I copied off of a website some time ago and for those interested would like to relate my experiences with it and hope others might post theirs too. In the past I have read posts of those who have used this developer but their experiences were all with Fuji papers and I have seen none with Kodak Endura paper, which is what I use. The posts with Fuji papers were generally positive.

    Here is the formula I tested:

    Water, distilled 750ml
    Triethanolamine 6.0 ml
    Sodium Sulfite 1.0 g
    CD-3 5.0 g
    Potassium Carbonate 40.0 g
    Sodium Chloride 0.5 g
    Water to make 1.0 L


    To test the developer, I made a good print of a MacBeth color chart with Kodak RA-RT developer, to use as a reference, and used the same exposure time and enlarger settings when making test prints from the home brew developer.

    When used as directed, the developer gave dark and low contrast prints with Endura paper. It calls for a development time of 1 minute at 95 degrees F. After trying different formulations and time/temperature combinations I found that by simply lowering the sulfite to .2 grams (sulfite interferes with dye formation) the prints closely matched the Kodak print in contrast, density and color balance, and I could develop at room temperature for 1 minute, and at 85 degrees for 30 seconds! But I could see a reddish cast in the blacks indicating some crossover. A check of the pH showed it to about 11, so I added acetic acid to bring it down to about 10 which I believe is correct for RA-4, but the room temperature prints were now a little flat as if underdeveloped, so I increased the develop time to 90 seconds and the prints appeared nearly perfect. I could see virtually no difference between the Kodak print and the home-brew prints in the blacks and gray scale. Color patches were nearly identical. Shorter develop times at higher temps with the same quality might also be possible but I haven't tested this yet. IMHO, this developer can work well as a substitute for standard RA-4.

    But there is down side. The low sulfite results in virtually no storage life, in fact freshly mixed developer stored in a glass, filled jar started turning color overnight. It still worked fine but at that rate likely wouldn't last more than few days. This developer lacks the smelly preservative present in the Kodak developer, making it user friendly in the darkroom but not on the storage shelf. Perhaps someone with more chemistry know-how than I have knows a way to extend the life some while keeping the smell down. On the upside, the ingredients have a very long storage life.

    Hope all this is useful to someone out there.

    RPC

  2. #2

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    Thanks for that well written and easy to understand post. How easy is it to get these ingredients and how much does it cost for 1L of dev compared to Kodak dev?

    Thanks

    pentaxuser

  3. #3
    RPC
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    I can get all the ingredients from Photographers' Formulary except CD-3 which I get from Artcraft. I don't know the availablity in the UK or what PF or Artcraft will or won't ship there but surely there are some sources.

    I haven't computed the cost comparisons but don't see the formula as necessarily competing with Kodak or other chemistries but rather a way to go if standard RA-4 becomes unavailable, or due to cost or purchase volume considerations becomes unfeasable to the home printer, and the formula is also for the experimenter out there. I have stocked up on Endura paper, (and the formula ingredients) and I want to make sure I always have something to develop it with!

    RPC



 

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