off-topic: erasing acetate

[tape]

I am trying to find a method to erase an old 16mm film, in order to get a blank roll. Simply trying to remove the picture from it.

As I understand the material is acetate, as in record blanks, but I might be wrong. Im trying to find a method to remove it, so far with soap and water which did nothing...

thanks

[flozki]

most films after 1980 are polyester based..
so you have to check.
i dont know how to remove the picture....
flo

[motorino]

try with acetone... my father use it for assembly the film and remove the gelatine film (colour emulsion in films) ok

[tape]

thanks. I will try acetone.

[cuttercollector]

Are you trying to strip it down to the clear plastic base?
To cut grooves on?
To draw on for animation?
To coat with iron oxide to use in a "full coat" magnetic recorder?
Just curious.

[Steve E.]

I used to get clear blank 16mm film for drawing on w/ sharpies....GREAT project for a group of kids....one of the best. But at least back in the day, you could buy film that was already in this state. I wonder if that wouldn't be more time/energy efficient?

Does bleach removed emulsion? Can't remember.

[tape]

Yeah in trying to get to the plastic base, so I can draw sound and image.
I have been looking for blank film, but the probem is, that when you search the internet for blank film, it comes up with film with emulsion on, not just the plastic..

[motorino]

ask with a film distributor or copyer, i remember some parts when received a film its without emulsion, totally transparent

[nickripley]

could you find a splicing or leader film? that may be clear.

[cuttercollector]

Leader is not typically clear. "Splicing film" is just short chunks with adhesive on one side.
What is clear is reversal film exposed to light till it is all overexposed, then developed.
Get some unexposed cheap perhaps outdated black and white (or color) film (must be reversal), and run it from reel to reel and back in broad daylight, full sunlight, somewhat slowly. That should come back perfectly clear after development.
As a matter of fact, completly _unexposed_ to light NEGATIVE film should come back clear after developing too !

[Steve E.]

Isn't it OK to have clear film "with emulsion"? You can still draw on it. It's still clear.

[emorritt]

If I remember right, just put the film in a tank of Clorox bleach - it will remove the emulsion. Not sure if this will work with processed film though. I used to do this with 35mm slide (color reversal) film to draw on it. Drawing picture and sound on 16mm film... Norman McLaren would be proud.

[cuttercollector]

Hard to get a sharpie small enough to draw thos 15Khz. sine waves though....

[emorritt]

What McLaren would do for his "synthesized" sound tracks is he would draw large waveforms on long rolls of paper that looked to be about 8 to 10 inches wide, making calculations as to the ratio of what he was drawing versus what frequency it would generate once it was shot down to the sound track area of a strip of motion picture film. Exactly how it was optically reduced to the size of a variable area sound track I'm not sure, but he was producing synthesized sounds this way long before there was such a thing as an electronic synthesizer. If you can find some of his works such as "Dots" or "Neighbours", these were films that used the technique of drawing sounds then photographing them into the soundtrack area of the film. Some say that Neighbours was done with an early version of RCA's Mark IV, but I doubt it. McLaren was using drawn soundtracks all the way up through the 1970's even after commercial synthesizers became available. His animation technique was very mathematical and precise - certain images went with certain sounds, then he then combined the images and sounds throughout his shorts into some very very complex works. Some of the animated works are like a visual canon or fugue in form. Just search for him on You Tube and check out the films.

[tape]

thanks very much for the many suggestions.
I found a store that simply sells blank film:-)
that will make the whole thing a lot easier.

I have read that optical sound has a frequency response only up to about 8khz - but im not sure if this limitation has anything to do with the psyichal size of the sound area. For sure it requires an editor to size up the image..

Mclaren has made good stuff, but was very late in the art, as it started with Pfenninger and Fishinger, maybe as early as 1915 - a strangely abandoned art....

[Doug6N]

Prior to polyester based stock. I remember the image just falling off if any water got on it. Used to spit on the film to soften the emulsion prior to wet splicing. I spent a goodly number of years with motion picture projection. Installations and all that stuff.

35mm old mono academy standard was down about 18DB at 9K as I remember. We generaly used with 16mm a 7K alignment film for sound. The response was falling off pretty quick from 5K on. Still in all it sounded pretty good most of the time. Limited range yes. But very servicable.

Doug

[motorino]

the optical recording today its the better hi-fi support... but also expensive...

[Steve E.]

I recall using zip-a-tone for soundtracks. It was an adhesive-backed clear tape with dots or lines printed on it, for shading....used by cartoonists.


Do they still make that stuff? There was always a danger of it peeling off.