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  1. #11
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    There is an oxalate salt in the C41 and RA developers already. It is no problem.

    I had some CD-1, but when I checked it was bad. Sorry. All I have now is about 20 g of CD-6.

    PE

  2. #12

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    Another question: The process sequence outlined earlier by Ray specifies wetting as the final step. I assume that's a wetting agent like Kodak Photo Flo. Would there be any advantage to substituting C-41 stabilizer (the sort with formaldehyde)? Would that help improve image stability, or would that have no effect on this sort of film?

    Oh, and in case anybody comes across this thread in the future and is looking for the same, I found three US suppliers of small quantities of CD-1. See this post in another thread for details -- but check for updates, since I've not yet received the product I ordered.

  3. #13
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    Using a stabilzer with formalin depends on the types of couplers used at the time. With a given set of couplers in the absence of formalin, fading is rapid and a deep yellow stain is formed.

    Make sure too that the bleach is right for the film. Some films require a ferricyanide - bromide bleach and others require Ferric EDTA. This makes a big difference.

    PE

  4. #14

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    Quote Originally Posted by Photo Engineer View Post
    Using a stabilzer with formalin depends on the types of couplers used at the time. With a given set of couplers in the absence of formalin, fading is rapid and a deep yellow stain is formed.
    Well, I've run into no reference to a formalin stabilizer, so it appears none is required. Would using one hurt, though? I'd rather err on the side of caution, but I don't know which side that is!

    Make sure too that the bleach is right for the film. Some films require a ferricyanide - bromide bleach and others require Ferric EDTA. This makes a big difference.
    In another forum, somebody's posted the complete set of official formulas for the Svema film in question. (I'll post them to the chemistry section once I've gotten the film and tested it all.) Here's the bleach:

    K3(Fe(CN)6) [potassium ferricyanide] - 30g
    KBr [potassium bromide] - 15g
    K2HPO4 (Dipotassium phosphate) - 17g

    ... and the fixer, FWIW:

    Sodium thiosulfate*5H2O - 200g
    Sodium sulfite - 5g
    Na2S2O5 [sodium metabisulfite] - 2g

    I believe these are all to make up one liter. The developer formula is like the one posted in another APUG thread, but a little more dilute. There's also a "post-developer" solution of 0.2% sodium metabisulfite.

    I don't happen to have any dipotassium phosphate, but at least the Formulary carries it. Is that likely to be vital? Could something else be substituted? I'll buy some if necessary, but if it's not necessary, I prefer to have one less bottle in my darkroom....

  5. #15
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    The bleach formula is right, and any phosphate salt could be used as long as the pH is correct. That is what it is there for. Since I have no idea OTOMH what the pH is, I'm not sure what to suggest. As for stabilzer, if formalin is not needed then having it or not having it is irrelevant. If needed, the need is critical.

    HOWEVER, I stress again a point I made long ago. Formalin is used as a film preservative as well. Color films are particularly in need of a preservative, as silver is a preservative in B&W film, and there is none in color film after it is processed.

    Both formalin and silver inhibit bacterial and mold growth.

    PE

  6. #16

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    Quote Originally Posted by Photo Engineer View Post
    The bleach formula is right, and any phosphate salt could be used as long as the pH is correct. That is what it is there for. Since I have no idea OTOMH what the pH is, I'm not sure what to suggest.
    OK, thanks. I'm afraid I wasn't told the target pH, so I'll probably play it safe, buy some dipotassium phosphate, and go with the official formula. I'll just check my inventory of other chemicals to see if it'd make sense to order anything else at the same time....

    As for stabilzer, if formalin is not needed then having it or not having it is irrelevant. If needed, the need is critical.

    HOWEVER, I stress again a point I made long ago. Formalin is used as a film preservative as well. Color films are particularly in need of a preservative, as silver is a preservative in B&W film, and there is none in color film after it is processed.

    Both formalin and silver inhibit bacterial and mold growth.
    I read this to mean that the formalin won't help with dye stability (assuming the lack of any formalin in any formula I've gotten is correct), but it may help prevent the growth of mold and bacteria on the film. In this case I'll use the Kodak C-41 stabilizer as protection against mold.

    Thanks for all your help on this; it's useful to have these gaps filled in!

  7. #17

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    I have developed svema MP film with normal c41 chem, no problems and it looks very cool.

  8. #18

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    An update and problem: My CD-1 supplier has had the CD-1 on back-order for over a month, so I decided to give it a go with CD-4 instead of CD-1. I doubled the amount of developer in the formula but otherwise mixed the developer as per the instructions I've got. Unfortunately, I also forgot the dipotassium phosphate in the bleach (full formula in post #14). The result of processing my Svema CND64 film was a completely blank roll (well, half-roll, since I cut it in half; see below). I was a bit surprised to notice that the processing instructions I received called for two fix steps: One before the bleach and one after. I'd have thought that was an error, but the two fix steps had different times, so I followed the procedure. (In short, it was develop/post-develop (sodium metabisulfite bath)/fixer/rinse/bleach/rinse/fixer/wash.)

    For the second half of the roll, I processed it in stock NCF-41 with Kodak Flexicolor bleach and fixer, just as if it were normal C-41 film, but with an 8-minute rinse between developer and bleach. (I chose NCF-41 rather than a more conventional C-41 simply because NCF-41 is supposed to be used at room temperature and I didn't want to stress the emulsion with a 100F development or guess at the development time at a lower temperature.) This produced a nearly blank half-roll; there are very faint images visible on the negatives. I can't tell from an "eyeball" inspection if the images are color or if they're the remnants of silver images that didn't get completely bleached away. When the film is dry I'll try scanning to see if the scanner pulls color out of these images.

    Could my bleach compounding error have caused the bleach to completely ruin the image? Should I try again with a different amount of CD-4, or with CD-3 rather than CD-4? Was the two fixer baths really an error? My inclination is to try another roll cut in half or thirds, with part done in a B&W developer and another part or parts varying something else to try to get this to work. I'd appreciate any suggestions for what to try. Thanks.

  9. #19
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    The bleach should not totally ruin the color image IMHO. If there is no color image, either the first developer fogged the film, the reversal was bad, or the color developer was ineffective.

    PE

  10. #20

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    This was a negative film with negative processing, not a reversal film. The film base is about as dark as unexposed and normally processed C-41, although the color is different. Thus, I don't think the image was obscured by fogging.

    The film's not quite dry yet, so I have no scans of the very faint images that survived the processing of the second half of the roll.

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