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  1. #1

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    Pyro Negative Glow

    Quick questions for the pyro/alt printers...

    Do pyro developed negatives proportionately fluoresce under a uv light source? Or.... does the pyro powder itself happen to fluoresce under a uv light source? If not I have some strange voodoo going on in the darkroom.
    Thanks... Annie

  2. #2

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    Hi Annie,
    Are you talking about what happens when you place an ABC develped negativein the stop bath after developing or something else? This is pretty common with ABC pyro and it happens there without the UV light source. It has been discussed at Michael Smith's site a few times., e.g.,
    http://www.michaelandpaula.com/mp/Az...GID=8322&CID=2

    What developer are yuo using? PMK or Pyrocat HD don't fluoresce like ABC does.

  3. #3

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    David,

    That effect is indeed interesting but it is not the effect I am experiencing. I am using an organic home brew source for pyrogallol/tannin and mixing it up similarly to the old pyro formulas. I had not noticed the effect until the negative was illuminated with an UV light source... the brew and the neg are glowing a reddish purple... I guess I should stick with the proven pyro formulas as I assume a negative that is emitting it's own light is most likely counter productive to the process. Thanks for your assistance, Annie.

  4. #4

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    Hmmm, that's a difficult thing - many organic compounds will fluoresce more or less strongly in UV, especially the ones containing aromatic structures (like pyrocatechol and polyethylenetereftalate (PET) of film base). That's why the glass plates are still used instead of film to record UV spectra in quartz spectrographs. Does your neg itself fluoresce? If not, the brew can indeed contain something that gives off a fluorescence with this kind of UV - pyro itself, or some impurities in it.

  5. #5
    TheFlyingCamera's Avatar
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    I've noticed under my BLB bulbs for palladium printing that my negs done in PMK tend to glow purple-ish, particularly around the edges. As a whole though, they don't exhibit any particular phosphorescent effect.

  6. #6

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    Well then it is possible an element in my raw material is similar to the commercial pyrogallol or it is just an impurity. Under the BLBs both developer and the processed negatives glow with a surprising exuberance... the raw plant material does a full red fluorescence. I wonder if it is binding with the gelatin or the silver in the negatives. One of the reasons that I tried the material of this particular tree (arbutus) is that the bark is comprised of one of the highest natural occurring concentrations of tannin and 'pyro' on the planet. Also its form of tannins have been shown to interact with iron salts... so I thought it might be amusing to see how it worked in the alt mix.

    ... actually now I am really wondering is how I can get a UV light source into the woods at night to photograph one of these glowing trees... I'm hopeless...

    Cheers, Annie

  7. #7
    jimgalli's Avatar
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    Why Annie! I seem to recall you saying something to the effect that all of us Pyro people were completely wacked. And now I learn you're out scraping tree bark?? Oh my. Ultimately I think the phosphorescence is what we're after. It makes the printing process so much slower and more delicious to the end result. One thing I do note. The PMK negs with the deep green stain print at least a third slower in the UV cooker than the PCat negs do. That isn't a preference though. I've got some that have to be under 8 lamps for 32 minutes. Too long perhaps.
    He is no fool who gives what he cannot keep..to gain that which he cannot lose. Jim Elliot, 1949

    http://tonopahpictures.0catch.com

  8. #8

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    Jim..... let me make this perfectly clear... no trees were hurt during this experiment!! The arbutus is a strange tree it sheds it's bark not it's leaves.

    ... : ) Annie

  9. #9

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    Arbutotype!!

    LOL..... I think I discovered my own little photographic process... I exposed one of my glownegs onto my 'special' paper (did I mention that the paper is ever so smooth!) coated with ferric oxalate under UV light. The image appeared instantly when dunked in the arbutus bark distillate (no other additives). The image is 'cool black'.

    I'm thinking of changing my name to DiAnnie Arbutus..... workshops coming soon... ; )

    Cheers.

  10. #10
    jimgalli's Avatar
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    Oh sure! Now I'll be looking all over Nevada for an Arbutus tree. Any tree for that matter.
    He is no fool who gives what he cannot keep..to gain that which he cannot lose. Jim Elliot, 1949

    http://tonopahpictures.0catch.com

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