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  1. #41

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    SO which developer should I use to get the best chemiluminesence - PMK, WD2D+, or Pyrocat??? ;^)

  2. #42
    keithwms's Avatar
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    Probably all the pyros will do this but I have only mucked with wd2d+ so I can't say for sure.

    Let me add a few details that may or may not affect your observations.

    (1) When mixing up my parts A and B, I took the admonition to use steam distilled water seriously. I did not, however, leave the water in an open container to "allow time for excess oxygen to leave the water." I figure that if it were that serious an issue then one might vacuum cap the part A and part B or at least bubble N2 through it before sealing. Maybe I'll do that next time... store my part A and B in wine bottles.

    (2) I tried to generate the CL with freshly mixed part A+B and didn't see it nearly as strongly, so I think the developer needs to "age" and you're probably best off pouring some stop bath into the dev bath after you've finished a batch of processing. This is consistent with Ole's comments about polymerization.

    (3) I also thought I might intensify the CL by mixing fresh part A+B + stop... in fact I saw little if any CL. So again there appears to be an issue of letting the developer crosslink. I suppose silver may act as a catalyst for the polymerization.

    (4) I do my wd2d+ development at room temp or 23.5 C.

    (5) Finally, the strongest observation of CL was when I transferred the film directly into the ilfostop, with no water bath in between.

    Enjoy the pretty colours! Next time I have a wd2d+ session, I'll try to film it.
    "Only dead fish follow the stream"

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  3. #43

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    Does that glow produce a tan?

    Actually, what is happening is called chemoluminescence. When pyrogallol, the main developing agent in WD2D+, goes from an alkaline to acid environment, it gets so happy to glows for a few moment. So when you pour the stop bath into the developer it emits light for a short time. If you are tray developing and your eyes are fully dark-adapted, you can often see the negative light up when you place it in the stop bath. But fear not, there won't be any fogging as development is complete and has been stopped. To my knowledge, pyrogallol is the only chemoluminescent developing agent. Just another good reason to use pyro!

  4. #44
    keithwms's Avatar
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    Thanks John, nice to hear from the creator of this lovely developer and interesting phenomenon. And you are the first person to confirm that I am not crazy, so thanks for that
    "Only dead fish follow the stream"

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  5. #45

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    A quick check of the dictionary corrects my spelling: it's "chemiluninescence". You're definately not crazy!

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