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Thread: Pyro stain fading under UV

  1. #1

    Join Date
    Oct 2006
    Location
    Columbia River Gorge, SW Washington
    Posts
    52

    Pyro stain fading under UV

    In the past I have used PMK with 8x10 Tri-X film to do my platinum printing. I find that the pyro stain facilitates in the creation of the platinum image. Once I inadvertantly put the vinyl border masking material on the base side of the negative and after an extended exposure I noticed lines on my negative where the masking material was in place. Has anyone else who may be reading this post had this experience? Lately I've taken to shooting with the Toyo CF 4x5 (about 1/3 lighter in weight than my 8x10) and then making enlarged negatives with APHS film (as described by Bob Herbst on his web site). This way I will be protecting my precious original negatives from damaging UV light. I would be very interested in anyone's thoughts on this.

  2. #2
    Clay
    Join Date
    Feb 2002
    Location
    Asheville, NC
    Posts
    364

    Re: Pyro stain fading under UV

    I have observed the same effect. However, unless you plan on making editions of 50 or a 100 prints, I doubt whether it is really worth worrying about. Concievably, you might have to goose the contrast mixture for later prints from the same negative, I guess. It is much more likely that you could lose a negative to an incompletely dried piece of sensitized paper, IMO.

  3. #3

    Join Date
    Sep 2003
    Location
    South Carolina
    Posts
    5,505

    Re: Pyro stain fading under UV

    If memory serves Kerik Kouklis made the same observation many years ago on the alt-photo-process list.

    Like Clay, I have also observed the same effect. Based on data from a couple of rudimentary experiments my belief is that most of the loss of transmission density ocurrs during the first ten or twenty exposures to UV light, assuming exposure times of 5-10 minutes, and the total effect is quite small. So I agree with Clay that it is probably not something one should worry about.

    Sandy King



    Quote Originally Posted by clay harmon View Post
    I have observed the same effect. However, unless you plan on making editions of 50 or a 100 prints, I doubt whether it is really worth worrying about. Concievably, you might have to goose the contrast mixture for later prints from the same negative, I guess. It is much more likely that you could lose a negative to an incompletely dried piece of sensitized paper, IMO.
    Last edited by sanking; 25-Oct-2006 at 14:22. Reason: Spelling

  4. #4

    Re: Pyro stain fading under UV

    Yes, I noticed that effect several years ago. I agree that the change has little effect on the printability of a negative.
    Kerik Kouklis
    www.kerik.com
    Platinum/Gum/Collodion

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