Gearhead_Shem_Tov - 19-1-2012 at 02:28
I want to play with making cellulose acetate and/or triacetate, but I don't want to mess with acetic anhydride. Is there a beginner-friendly way to
go about this, perhaps starting with waste movie film stock? I'm looking for a method that can produce a high-quality film, something optically clear
even though perhaps starting with film negatives or reversal positives.
Starting with developed film would mean removing the silver and any dyes (if colour film), which would involve bleaching, right? And something to
strip the gelatine off. Or would just stripping the gelatine emulsion do most of the job of cleaning the film base?
Next I imagine grinding the cleaned film up, but what would be a suitable solvent? Acetone?
-Bobby
AirCowPeaCock - 19-1-2012 at 07:30
Try paint thinner, it will dissolve just about anything. But I wouldn't expect to get a-lot of hand outs on this forum..your going to have to put in
some effort yourself...
Unexposed acetate film
Gearhead_Shem_Tov - 19-1-2012 at 14:45
I've remembered an old trick from Super 8 filmmaking to make transparent leader: using ordinary household bleach to strip the emulsion and rem-jet
anti-halation coatings from unexposed film. The emulsion is gelatine-based, of course, and the rem-jet uses a cellulose acetate phthalate binder, and
both respond well to an alkaline bath. Unprocessed Kodachrome is handy in this case because there are no dye couplers in the emulsion, as a
consequence of which the emulsion is thinner.
OK, to work:
First I broke open an old cartridge of unexposed Kodachrome film (which is on triacetate) and let the film soak in bleach overnight. I then
mechanically removed the gelatine and rem-jet coatings (mostly). Another treatment and some rinsing should do the trick.
Next up will be grinding the crude stock. Any ideas for this? I suppose if I have to I can toss it in a food processor.
Finally, I'll need to dissolve the granules. For the triacetate I plan to use DCM and methanol. Assuming I get most of it to dissolve cleanly, is it
as simple then as filtering and evaporating the solvents off to purify it?
-Bobby