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Author
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Topic: Scratch treatment ...
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Osi Osgood
Film God
Posts: 10204
From: Mountian Home, ID.
Registered: Jul 2005
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posted September 20, 2009 03:31 PM
... not as much fun as shock treatment, but a fun challenge, mind you.
I thought about this as, now that I'll finally be getting my "Popeye" film, with a few scratches. They are not deep ones, so this should be a rather easy process.
I have noted however, through trial and error, how to clean and how to not clean films. I once recieved an absolutely HORRIBLE print of Gullivers Travels. I have never seen worse. The amount of dirt on that print looked like some Aussie dragged it throuigh the mud a number of times. (I say "aussie", as I bought it from a ebayer in Australia).
I took it and first used some dish-washing soap, (very light amount) and I was amazed as to how much of it (the dirt)came off. Not all of it, mind you, but a good deal of it. After a day or two, I gave it a normal water bath. After each wash, I dried it with a non scratching clean cloth which, of course looked like IT was dragged through a mud bog.
What surprised me was that, though I knew that it was terribly scratched, I was surprised as to how much the scratching was diminished on the print. It was there, of course, but the dirt was cleaned out of the scratches to a great degree.
I was so pleased with myself on that venture, that I took a dirty old print of STAR WARS 400ft and did the same process with it, and while it did clean the print pretty darn good, it also lifted off the mag stripe a good deal, which wasn't too bad, as it was in bad shape, but I learned my lesson.
Of course, you can never get rid of an existing scratch, to be sure, but a lot can be done to diminish the impact of scrtaches.
What do you folks do concerning the scratches on your prints?
I thank you for your time.
OSI
[ September 22, 2009, 08:45 AM: Message edited by: Osi Osgood ]
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"All these moments will be lost in time, just like ... tears, in the rain. "
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John Whittle
Jedi Master Film Handler
Posts: 791
From: Northridge, CA USA
Registered: Jun 2003
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posted September 22, 2009 03:13 PM
There are really two topics here. Film cleaning and Film treatment to reduce abrasion or scratches from appearing on the screen.
First for cleaning. In the old old days, film was cleaned by hand with black velvet cloths which were moistened with white gasoline. While the work benches wre well ventilated, they were still highly dangerous. This was the method used by no less a laboratory than Technicolor. The nap of the velvet is very good at catching dirt and not gouging the film.
As for aqueous cleaning. This was been used and experimented with forever. A common practice in the laboratory was called "re-wash" where the print was run though a processing machine again and properly washed and dried. There are also cleaning machines (I read of one the other day in a 1958 Journal of the SMPTE and there has been more recent work by the Research Group). A very mild detergent with only fluid agitation and then a wash and air squeege and dry. Photoflow is needed for the final wash to prevent water spots on drying. There have been experiment with various detergents including the new citrus based materials.
As for scratch treatment, there were basically two methods employed and both have real downsides. The first for the cell or base of the film where a solution similar to film cements (of course this won't work for estar based films) is applied to the film and it's drawn over a highly polished chrome drum which smooths the base and then the solution evaporates and the film is supposed to be like new. Usually it's also warped.
Then there were treatments for the emulsion. If your mark goes deep enough to produce a color on the screen forget it. In this method a solution is applied as above but it is a clear gelatin mixture which is smoothed over the emulsion filling in the missing material. In effect this is what happens with liquid gate where a solution with the same refractive index is used to fill the missing void.
Again this usually results in a warped print with strange winding characteristics. Back when we did this, it was mainly a way to get a few more months of plays out of a print before it was dumped.
For the real bad news, don't every try these solutions with any magnetic stripe material. All it will do is dissolve the stripe and smear it over the base of the film. If its a non-standard winding or a laminated stripe, it will likely just be removed in the process. In any event it'll leave a mess.
In the golden days of 16mm print distribution to tv stations, most film chain projectors (the good old Eastman 285) were fitted with a pad assembly after the feed reel and before the film entered the projector. This pad was "drip feed" Ecco 1500 or the like which "cleaned" the film and since the fuild didn't evaporate until after the film had passed the gate, had a slight liquid gate effect as well.
If you're old enough and actually saw film on television as a kid (up to about the 1980s) then you saw prints which were handled this way. (You also probalby saw tons of little cue marks which were added to syndicated prints by each television station they visited.)
It's worth noting that the "solutions" used for scratch treatment were considered trade secret and I don't think there are published formulas.
John
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Kodak Movie Film Cleaner, which sadly is no longer available, used to make light scratches nearly invisible.
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