after a 15 minute search, which is long for my strike out, I’ve concluded that large lith film is no longer readily available.
this may be a partial explanation of why x-ray film has so many advocates. Of course my need for the larger lith film was so that I could do lith type work. The output industry has moved on. Printers seem to burn plates directly, or they use a variant, enhanced digital printer to “burn” the film after being composited by computer. The world has unified behind the digital workstation as a key component in the process.