A friend of mine recently gave me a 35mm film bulk loader from a darkroom that closed down at her school. There is film in it and on the bottom it is labeled direct reversal duplicating film. When I opened the compartment with for the cassettes i saw that the film was red and almost completely transparent. I have had a hard time finding a clear definition of what it is from google so I came here. I hope this is the correct category. What is this film? And how can I use it? Thanks.
It's probably Kodak 2468, a duplicating microfilm. Develops as a positive in D-76. ISO speed something like 0.5, really really slow.
I have been using a similar (or the same) emulsion for years; Direct Motion Picture Film 5260. This film used to provide cheap "slash prints' for the sound mixing studio to use. It's a very exotic emulsion; an actual solarizing emulsion. It is designed to give a direct duplicate of a negative or of a positive by giving it around 1000 times the exposure that a negative working emulsion with similar fine grain would require. It has extreme resolving power: 1000 line pairs / mm at 1000:1. I have been developing it in D-97, Kodak's standard developer for motion picture B&W positive. I find that I can control the gamma like no other film I've used. One of the things I find it very useful for is making duplicate negatives with dramatically altered curves. I have used it for capture, and I agree with John Shriver's estimate of the speed. by exposure series, I arrived at an ISO speed of 0.5 when developed in D-97. This translates to f1.4 at 1/60th of a second in bright sunlight, so it can be used hand held. I would recommend using a more active sodium carbonate developer like D-19 or even Dectol/D-72.
