Question regarding Cat-P-TEA and Pyrocatechin in general...

Discussion in 'Black and White' started by al_divenuti, Jul 2, 2006.

  1. Having had some success with Pyrocat-HD and bemoaning the short shelf-life of
    the stock solution kits from the Formulary, I recently took it upon myself to
    mix up some of Patrick Gainer's Cat-P-TEA using the recipe in the Photo
    Techniques article of a couple years back. To do so, I ordered 100g for
    Pyrocatechin from the Photographer's Formulary.

    Despite great care in the mixing of the stock solution (and I have prior and
    successful experience using TEA-based developers) it hasn't been a success.
    Even extending development times to 13.5 minutes for 400TX I'm left with flat,
    grainy negatives that show no sign of staining. They look nothing like my
    negatives developed in Pyrocat-HD and Cat-P-TEA's own formula is clearly
    inspired by the former (think Pyrocat-HD with TEA substituting for the
    Carbonate and the absence of the Potassium Bromide).

    So what's going on? I'm using Formulary TF-4 to fix (which is alkaline and
    should not inhibit the stain) and no Hypo-Clear or dilute Sodium Sulfite after-
    bath.

    I did notice that the Pyrocatechin that the Formulary sent me looked odd.
    There was a mixture of small off-white granules plus some significantly larger
    leaves that were flat and triangular or rhobmic in shape. Most of the larger
    leaves were medium to dark gray in color and gave off an acrid odor. Not
    having experience with Pyrocatechin before I don't know whether that is normal
    or not.

    Can anybody tell me what is amiss? Is it something in my process or simply bad
    Pyrocatechin?
     
  2. There has been a discussion on APUG about pyrocatechin from Photographers Formulary.
    Apparently you are not the only one who has experienced problems with this product.
    I don't understand the short shelf life of Pyrocat HD from PF. I mix my own from some pyrocatechin I have had for years. I have no problem with shelf life either of the powder, or the Part "A" of HD.

    Perhaps it is time to invest in some pyrocatechin from another source, B&S or Artchem.
     
  3. Hi Al.

    I have done a lot of testing of catechol-based developers, and in my experience, TEA doesn't provide enough pH to get the catechol working, except with VERY long development times. Your catechol is probably fine, I have a very large jar of similar looking stuff that works perfectly, and is marked with an expiration date of '08 fresh from the seller.

    When I want to use a catechol developer, I use Hypercat; a non-superadditive developer that contains only catechol and a tiny amount of ascorbic acid in the propylene glycol A solution, and a carbonate B solution. It is extremely simple, economical, and effective, producing the sharpest negs I've ever seen. Good luck.

    Jay
     
  4. Can't tell you what Pyrocatechin is suppose to look like but I have been using the Formulary's Pyrocat kits for over a year now and haven't had any problems with shelf the of the stock solution. I redistribute from the supplied bottles into tiny glass ones to minimize exposure to air. It gives repeatable results to the last drop so far.
     
  5. I recommend Pyrocat MC stored in propylene glycol. It has no sulfite. A small amount of triethanolamine and water is used to free the metol base from the hydrosulfate. 2.5 grams of metol, 4 grams of ascorbic acid, 5 grams of TEA and a teaspoon of hot water are stirred together to make a slurry. 750 ml of propylene glycol and 50 grams of catechol are added and the volume brought to 1 liter. Heat to about the temperature of drinkable hot coffee. Use about as you would Pyrocat HD. You may find it a little more potent.

    It is especially good at 1:1:100 for minimal agitation development. You may be able to get a kit or the ready mixed developer from Photographer's Formulayr.
     
  6. I just came out of the darkroom for a break and read Patrick's response. I happened to be printing some snapshots from recent graduation parties on HP5+ using the MC version of PyroCat that Patrick referred to. These were almost printing themselves and giving smooth skin tones, good shadow detail and well controlled highlights. 1:1:100, one minute gentle inversion, 10.5 minutes. Hexar 35/2.0 @200. My limited scanning abilities will limit what comes through in this small file but I would heartily recommend giving this long-shelf life version a look.....
    00HEZK-31079384.jpg
     

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