Film-Tech Forum ARCHIVE: Removal of Emulsion from film?

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Posted by Robert Burtcher (Member # 3227) on 03-06-2006, 05:08 AM:

Okay, a rather odd question to be sure. I am considering adding some clear leader to the tail of our prints to help protect them, but I'm fairly sure the money men won't go for that. As an alternative, I'd like to make some "Poor Man's" clear leader by removing the emulsion from old, scratched trailers that get thrown in the trash. I know water softens the emulsion, but it doesn't wash it away. Is there any way to easily wash away or otherwise remove the emulsion?

Or is this really even worth my time to think about? (I get the feeling it's not)

Posted by Kris Dirix (Member # 3012) on 03-06-2006, 05:20 AM:

use sodium hypochlorite (= Bleaching Water)
[beer]

Posted by Robert Burtcher (Member # 3227) on 03-06-2006, 06:18 AM:

I just tested that on a scrap of film... Holy cow, that works insanely well! Thanks!
Just a tip for you all if any of you try to do this, though: the reaction seems to evolve a lot of gas that might be chlorine. It sure smells like a pool.

Posted by Randy Stankey (Member # 64) on 03-06-2006, 08:40 AM:

quote: Robert Burtcher

...the reaction seems to evolve a lot of gas that might be chlorine. It sure smells like a pool.

It is clorine. Almost the exact, same thing as pool clorine except there are a few extra ingredients to make it better for washing clothes and stuff with.

I've used hot water and Clorox to remove emulsion several times. It works well but it can be a lot of work. You have to rinse the film really, really well to get all the chemicals off or else you will unwittingly clorinate your projector and all the film that runs through it.

Posted by Monte L Fullmer (Member # 2797) on 03-06-2006, 12:50 PM:

I used to do the same trick when making 8 and 16mm leaders - fill a bucket up with a good concentrate of bleach water (good 20% mix), take some 16mm film and fill the bucket and let the goo steep and brew for an hour. Then, drain the bucket (all of this was outside) and throughly rinse off the film and hang the film on the clothesline to air dry.

Posted by John Pytlak (Member # 331) on 03-06-2006, 02:39 PM:

If you are just looking for protective tail leader, why must the film be clear? Just use old trailers, but be sure to cue the film so sound and picture don't end up on screen.

Film emulsion is made of gelatin, so hypochlorite bleach solution will dissolve it. Protein enzymes could also be used (e.g., Papain, Bromelain).

Posted by Bill Enos (Member # 440) on 03-06-2006, 05:03 PM:

I use old trailers, just to remind myself I put a couple fat scratches the length of them using a box cutter

Posted by Robert Burtcher (Member # 3227) on 03-06-2006, 07:03 PM:

quote: Randy Stankey
It is clorine. Almost the exact, same thing as pool clorine except there are a few extra ingredients to make it better for washing clothes and stuff with.

Okay, that's what I thought. I'm assuming that the reaction between the sodium hypochlorite and the geletain emulsion is freeing elemental chlorine gas, as it did bubble pretty good.

quote: Randy Stankey
You have to rinse the film really, really well to get all the chemicals off or else you will unwittingly clorinate your projector and all the film that runs through it.

I thought that might be an issue. I might not do this project then, just to be absolutely sure I don't mess anything up at work.

quote: John Pytlak
If you are just looking for protective tail leader, why must the film be clear?

Simply to help reinforce the fact that it's just protective tail leader and not part of the film. Since I'm not the only one at my theatre that breaks down prints, if I do add the protective tail leader, I want it to be plainly obvious that it is not a part of the film.

[ 03-06-2006, 10:24 PM: Message edited by: Robert Burtcher ]

Posted by Monte L Fullmer (Member # 2797) on 03-07-2006, 12:11 AM:

..course, if one wants clear film, a lot of features nowdays have gobs of clear leftover film at the end of the tail leads of the reels that one can snip off.

..these make good film wraps so if one uses a chunk of this clear stuff as a wrap for the filmroll, you can see the title through the clear wrap.

Posted by Dominic Espinosa (Member # 2122) on 03-07-2006, 12:25 AM:

quote: John Pytlak
Just use old trailers, but be sure to cue the film so sound and picture don't end up on screen.

That's what I do. I flip it over so the digital systems don't see a proper track.