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  1. #41

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    Just want to add a quick note to this thread regarding Dura-Lar Wet Media film. I was at the art supply store the other day, and they had a pack with a dinged-up corner that was significantly discounted. I have no use for it, really, but I grabbed it thinking of this thread. If anybody wants to try it (US only, probably, otherwise postage gets too high), I'd be glad to send out a few 11x14 sheets rolled in a tube, or cut down to 7x11 for mailing flat. I'd ask that you reimburse me for postage and shipping materials. If anybody's interested, let me know via PM.

    I took a little corner of it and ran it under water. There is definitely a clear coating that got a bit slippery for a second before it rinsed off. Have no idea what it was. The highlighter markers that I had laying around (which I thought were water-based) didn't behave any differently between the wet media film and regular dura-lar, so maybe they weren't water based, or...

    Anyway, just wanted to mention this. If it works, it might be a good option for those who wish to avoid the larger purchases required for the 3M film if you're making sheets.

    --Greg

  2. #42
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    Greg, funny you mention this. I emailed Grafix a week or two ago asking about the wet media film with gelatin and they were intrigued, so they sent me a couple sheets to test. Just arrived today!

    I only say something to account for why I won't be raising my hand, but dang what a coincidence.

  3. #43

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    I was wondering -- I use imagesetter imaging film in a small offset printing business that I have. Often the film gets messed up (someone forgot to proof the page, etc). If I bleach the emulsion off of the films that cannot be used to make printing plates, will the substrate that remains be suitable for coating with emulsion without further preparation?

    This would mean that instead of the used film being hazardous waste, the bleached off emulsion would be, and I would have to figure how to dispose of it, but the clean substrate could be used for coating if I ever get around to making my own emulsions. And I have quite a lot of the stuff.

  4. #44
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    Well, if you literally bleach off the emulsion, probably not. But, if you bleach out the silver, then the remaining clear gelatin will make an excellent substrate. So yes.

    But most subbing layers on film are one-and-done. For instance, if you wet the Photo Formulary melinex before coating, it becomes useless. That's why I say that if you literally mean removing the emulsion from the film, then the remaining raw PET/TCA will probably not accept a coating.

  5. #45

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    OH - OK - thanks for the explanation. I had read some of the threads here but only quickly, and I had thought that the subbing process modified the surface of the plastic to accept an emulsion, in a way that would permanently affect the plastic. I did not realize it only worked once! I was talking about removing the emulsion - I thought that bleaching and fixing the existing emulsion could be a bit costly, but it is worth considering. Ferri bleach and fixer do last rather a long time.

    But wouldn't adding a new emulsion make the resulting total gelatin layer(s) rather thick?

  6. #46
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    I suppose adding a new layer would make it somewhat thick, but not necessarily too thick. Any machine coated film is going to have a rather thin coating to begin with, so it shouldn't add much more than several microns.

    As for their subbing treatment, having to guess here, I would bet that they coat with an inline corona discharge unit. The pre-subbed substrates on the other hand probably receive a corona treatment, and are then treated with an ultra-thin subbing layer for coating later.

  7. #47
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    Some subbing layers can work more than once. I would not vouch for quality though due to induced imperfections.

    PE

  8. #48

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    If I did remove the existing emulsion with chlorine bleach, could the remaining substrate be re-subbed?

  9. #49
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    Probably not at this point. It would have to be re-bombarded with a static charge. That is, if the subbing is gone.

    PE

  10. #50
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    I'm posting this just for reference; a technique for treating raw PET with potassium hydroxide to roughen its surface texture and thus create a hydrophillic subbing. Umut came across it.

    Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 12, No. 2, pp. 118–120, March–April, 1976. By I. Astrina, S. V. Vlasov, R. D. Gorak, Yu. V. Moiseev and Ya. A. Serednitskii

    http://www.springerlink.com/content/kgwn7n442v57u30q/
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