pyro hd stain question

Discussion in 'B&W: Film, Paper, Chemistry' started by eddie gunks, Feb 3, 2008.

  1. eddie gunks

    eddie gunks Member

    Messages:
    1,159
    Joined:
    Dec 14, 2005
    Location:
    Saugerties,
    Shooter:
    Large Format
    hi all,

    i just began to use pyro hd recently. i just finished off my first set of small bottle. i have been getting good results but now i am getting different stain colors.

    i am using foam100 (and arista.edu.ultra). a few weeks ago i exposed the film at 50asa and used 1:1:100 at 70 degrees for 12 min. the stain looks to be a brownish color. yesterday i shot the same film at 100asa and used 1:1:100 at 70 degrees for 14 min. the stain is not brown in color at all. it looks more like the negs i have souped in hc110. what happened? i did everything the same except what i have listed above.

    thanks for the help.

    eddie
     
  2. Tom Hoskinson

    Tom Hoskinson Member

    Messages:
    3,879
    Joined:
    Mar 7, 2004
    Location:
    Southern Cal
    Shooter:
    Multi Format
    Stain is best judged with a transmission densitometer ( you can use the blue channel on a color densitometer or a UV densitometer) or you can print the negs. Visual evaluation of stain is almost never successful and can be very misleading.
     
    Last edited by a moderator: Feb 3, 2008
  3. snallan

    snallan Member

    Messages:
    523
    Joined:
    Sep 28, 2007
    Location:
    Cambridge, U
    Shooter:
    Multi Format
    Hi Eddie, I agree with Tom, it can be difficult to judge the stain with pyrocat-HD. Indeed my negs don't appear to have any stain (which worried me with my first attempt), so I bleached and fixed a dupe neg and voila, my stain image. :smile:

    I have used the HD with Bergger BFP200, Efke 25, and FP4+; same results with each.
     
  4. Chris Breitenstein

    Chris Breitenstein Member

    Messages:
    226
    Joined:
    May 29, 2007
    Location:
    Tucson Az
    Shooter:
    Multi Format
    Pyro staining is a funny thing. the more oxidized the developer is the heavier the stain will be. I have found that blotchy stain is a result of inattentive stopping, or developer soaked film being exposed to air too long. Remedy the first by stopping for between 10-15 seconds. film looses its slimey texture when the alkali in the developer is neutralized.
    I would recommend 4 things to reduce blotchy stain in negs, and uneven staining from batch to batch. 1) use Pyro as a one shot developer. this ensures that all your negs are processed in equally oxidized developer. 2) do not drain your negs between developer and stop bath. This reduces their exposure to air. 3) cut you stop bath with water. This wont help with staining but will reduce the likelihood of getting pinholes in you emulsion. 4) reduce stop bath time. 30 seconds is WAY to long. Fresh stop bath will stop development within the first five seconds, especially with the non penetrating properties of pyro developers.

    Yours:
     
  5. Tom Hoskinson

    Tom Hoskinson Member

    Messages:
    3,879
    Joined:
    Mar 7, 2004
    Location:
    Southern Cal
    Shooter:
    Multi Format
    Chris, pyrogallol and pyrocatechin based developers tan (thus harden) the surface of the gelatin. I've found that a water rinse is sufficient to stop development with these developer types.

    Again, use a densitometer to evalute image stain. Attempting Visual evalution (with your Mark I eyeballs) can be very misleading.

    Bleaching out the image silver (and leaving the stain image) can provide some insight - so can printing the negs.
     
  6. nworth

    nworth Subscriber

    Messages:
    2,199
    Joined:
    Aug 27, 2005
    Location:
    Los Alamos,
    Shooter:
    Multi Format
    I've used Pyrocat-HD enough to go through a couple of small batches, even though it isn't my primary developer. The visual impression of the stain isn't much in any case with this developer. Sandy's measurements show that it is very noticeable in the blue and UV areas, however. I've noticed that the visual impression of the stain changes a bit with the age of the stock solutions also. In my case, I thought the stain got less as the stock solutions aged. But the negatives don't seem to print any differently. Of course, I adjust time and contrast grade to match the individual negative, and since these were not controlled test exposures, there could be some difference. In any case, it is an excellent developer.