Rapid Fix and PMK Pyro

Discussion in 'Black and White' started by paul_brenner|1, Jan 24, 2004.

  1. A lot of good information and responses to my recent post, "New Tri-X
    and PMK Pyro". I wanted to start a new post to pursue a specific
    issue arising from it.

    Tim mentioned that rapid fix contains no acid. I indicated that I
    thought it did. I was wrong (at least for Ilford, which I use.) The
    ingredients are listed as: Ammonium Thiosulfate; sodium acetate;
    sodium sulfite; sodium bisulfite; and water.

    That being the case, would there be any advantage to using one of
    the "alkaline" fixers rather than this rapid fix, which seems
    reasonably close in formula to at least the alkaline rapid fixer
    shown in "The Darkroom Cookbook? (I wonder what the ph of this is
    compared to the "alkaline" fixers?)

  2. Rapid fixer withourt the hardener is not acidic and is not going to remove stain from a PMK negative. The alkaline fixers, in general, lend themselves well to the archival life of a print, if complete washing is done as is required. This is not to say that an acid fixer won't work.

    TF4 from photographer's formulary is an excellent product and works well for film and paper. It is alkaline, versatile and well suited to work with PMK pyro. I have yet to see a complete formula with the breakdown of different chemicals, but I find it to work well for any needs I have in enlarging (RC papers) and film. For azo printing (fiber based), I stick with the more traditional mix-your-own versions of sodium thiosulfate (plain old hypo). See michael&paula.com for a complete set of formulas and procedures for archival life of azo and fiber based papers in general.

    TF3 can be mixed with the darkroom cookbook's formula and is said to be another good fixer. I have not mixed any at this point. The big plus for most mixing at home is that the cost of bulk chemicals will be recovered over time if a constant supply is needed in the darkroom. This, and the ability to use fresh stock can be worthwhile.

    There is a point at which buying "store bought" is cheaper if you are using a minimal amount throughout the year and don't want to invest in a scale and an inventory of chemicals that sit on a shelf for months on end.
  3. I've used rapid fix (without hardener) with PMK for years with excellent results...HP5+.
  4. Sodium Bisulfite is acidic. That doesn't tell you what the pH is, but that it could be acidic.
  5. I use Ilford Rapid Fix or Kodak Rapid Fix with TXT+PMK. So far so good... Everything develops and prints beautifully...

    joe :)
  6. Someone e-mailed me and directed me to the Ilford website, where the technical data on the rapid fix indicates that the ph is 5-5.5, which is definitely acidic, though not excessively so.

    I guess that answers it. Like some of the respondents, I've always gotten good results using rapid fix, but may try the alkaline fixer.

  7. One advantage of an all-alkaline process (no acid stop bath, acid fixer) is that wash times are shortened. Even if you are satisfied with your staining, you might still find an alkaline fix useful. I've switched to using TF-4 with all my films.

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