I have had success using KODAK Aerographic Duplicating film 2420, estar base
film. It is 9 inches by 250 feet so if you can live with the 9 inch
limitation you have tons of film to experiment with. I bought mine from
Freestyle years ago for about $50. and have kept it frozen since. I use it
for producing photogravure positives, cyanotype negs, and it works nicely. It
is red safe light tolerant and develops well in Dektol 1:2.
I am very curious about the TYPON film you mentioned, primarily for the heavy
Estar base. The reason is I have been using KODAK XX Pan sheet film for
collotypes, printing directly from the film, but not only has the film been
terribly expensive, but now discontinued. Since the double Estar base is
all I am after ( I resensitize the film) I would be interested if you know
where I can find TYPON in the US or if anyone else on the server list can
recommend a large format double Estar base film. Thanks in advance. Janet
Flohr