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  1. #1

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    What the...! Luminous tape on 120 film?

    Alright, explain this to me: My technique for developing 120 film is to first roll up the film (away from the backing paper) and then of course peeling off the tape from the film, before spooling it for development.

    Today, I took a closer look when peeling the tape (my darkroom is really, really dark - nothing can be seen whatsoever even after 30mins) and, when peeling the tape, it became luminous! As the tape was being pulled off the film, the specific part being separated from the film at that moment emitted a clearly visible glow (similar to static electricity, although not clearly defined spark[s] - just a glow of sorts, I could have sworn it was blue).

    Any possible explanation, or has anybody else ever seen this?? Next time, I will try to pay attention as to whether this fogs the film (of course, it would not be a concern, as this is on the un-used edge of the film).

    I am flummoxed. I'd love to show you, but I think I'd need a DSLR that goes to ISO 25600 and an f/1.0 lens to capture this. But it's there...

  2. #2
    keithwms's Avatar
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    Static. It's quite a common occurrence with any tape. I see it all the time In practice it's not a problem because the tape isn't directly adhered to the film. I haven't seen any fogging from it. By the way, you also see this when you open photopaper...
    "Only dead fish follow the stream"

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  3. #3

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    static electricity --- just like you said.

  4. #4
    AgX
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    But there is also tension-luminescence.

  5. #5
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    I'm with AgX on this. It's common, it's normal, it's harmless, but it isn't static.

    It is the adhesive in the tape. Some of the energy you put in by peeling it off is released through tension luminescence in the adhesive layer.
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  6. #6
    Aurum's Avatar
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    Yank it hard enough and you might give yourself an X-Ray

    http://physicsworld.com/cws/article/news/36357

    Though admittedly they were cannoning that roll of scotch tape through the machine at quite a rate of knots
    "Flatter Me, and I May Not Believe You. Criticize Me, and I May Not like You. Ignore Me, and I May Not Forgive You. Encourage Me, and I Will Not Forget You."

  7. #7

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    What they said.

    You can just tear the tape at the line between the tape and the paper, but leave the tape on the film. I find the extra stiffness helps a little in getting it on the reel (stainless ones, anyway).

  8. #8

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    It's called triboluminescence. See this wiki
    Frank Schifano

  9. #9
    keithwms's Avatar
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    Oh I see, so it's not just an ordinary static discharge. Good to know.

    Banging sugar in the darkroom is something I have done, that is quite cool.
    "Only dead fish follow the stream"

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  10. #10

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    I have seen this also, only once I think or only once that it freaked me out.
    It was almost like some shone a bright flashlight right just for a split second.
    I can't say I saw any ill effects on the film but I wouldn't like to go trying to do it everytime.

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