>I have a 16mm proyector that i d like to modify to do as a
"workprinter".
Could anyone tell me how can i do this?<
Depends upon the projector. Basically, it has to be able to run bipack
through the gate (original and raw print stock.) If it can't do that,
forget it. You can test that aspect by interleaving a long length of
old film stock with another and wind them together on the same reel.
Feed them through the gate and onto the takeup. If the bipack won't
feed through the gate smoothly, or the drive sprocket teeth are too
shallow to feed the film in and out, it isn't going to work.
If it does, then you'll want to do some tests on old film to see
whether or not the gate will scratch your original, since the bipack is
twice the thickness the gate was designed to take.
If it passes these tests, you'll need to rig the lamphouse with a much
smaller lamp on a rheostat to control exposure. I'm assuming you want
to print B&W. If you are trying to do color you are going to have an
issue with the color balance of the source, especially when dimmed by
the dimmer.
You can either workprint relatively short lengths by laboriously
interleaving them with print stock in a darkroom, or designing a
separate supply and takeup system for the stock so you can do longer
rolls. The projector will have to be used in a darkroom and you'll
also have to mask off any light leaks.
We did this successfully in the 60s with an old RCA sound projector.
Wade K. Ramsey, DP
Dept. of Cinema & Video Production
Bob Jones University
Greenville, SC 29614