This is topic Emulsion Stripping in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Jeff Taylor (Member # 443) on 12-17-2001, 01:54 PM:
Last weekend I got a print in and spent some time re-leadering it and checking the splices. At one point I found 3 rather clumsy tape splices virtually next to eachother in a section of the film where the continuity would not be a problem and decided to replace the short section with one good "neutaper" splice. To avoid losing any more frames than necessary I peeled off the two end tape splices and was amazed when the emulsion came off with them! This was an early 1980's Eastman B/W print of a Paramount title which I PRESUME may have been struck by Technicolor for Universal. The emulsion is pristine otherwise. Anybody ever encounter this before, and why would it happen?
Posted by John Pytlak (Member # 331) on 12-17-2001, 02:13 PM:
Some splicing tapes could be so "sticky" that they could cause delamination of the emulsion, especially on older films and with tape that has been on the print for a long time. The "subbing layer" technology that adhere the gelatin emulsion onto the plastic support has greatly improved over the years.It's also possible that if that 20-year old print were stored improperly (sealed container with excessive heat and humidity), the acetate base could be starting to exhibit "vinegar syndrome" deterioration, which can lead to emulsion delamination.
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John P. Pytlak, Senior Technical Specialist
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Research Labs, Building 69, Room 7525A
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Posted by Jeff Taylor (Member # 443) on 12-17-2001, 02:20 PM:
Thanks, John. To me, as a collector, an "early '80's" print is not very old, but it would take more than my crystal ball to know what kind of tape the perpetrator used, and that was probably the cause. All I know is that it wasn't yellowed or noticeably thicker than normal. Still, I wish I had a penney for every splice I've pulled apart to remake, and this had never happened before.
Posted by Jeff Taylor (Member # 443) on 12-17-2001, 02:22 PM:
P.S.: I've got a very sensitive nose for VS, and this print had no odor, even out of the shipping container, so I think it's OK on tht score.
Posted by Brad Miller (Member # 2) on 12-17-2001, 02:46 PM:
It's not the tape. There is something that I cannot explain about black and white film stock where once a splice sits on a frame for a length of time (few months) it will take the emulsion off with it. I've tried the cheap crap all the way up to Neumade tape and it happens with all of it.(Disclaimer, this always happens with acetate stocks. Not sure if it is happening with polyester stocks as well.)
Posted by Leo Enticknap (Member # 534) on 12-20-2001, 09:48 AM:
Jeff - just because you can't smell vinegar yet doesn't mean that the process of deacetylation (vinegar syndrome) has not started. In fact, it's quite advanced by the time you can smell anything. The easiest way to identify elements in an early stage of vinegar syndrome is to use acid detection (a/d) strips.