Although graphic arts films will become harder and harder to find, technical 'line film' is still used in printed circuit board manufacturing and for the production of precision optical masks.
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I have not tried these films with continuous tone processing, as with Soemarko LC-1 developer, or with reversal processing for enlarged negatives.
If you are looking for enlarged negatives the direct positive X-Ray duplicating film works well, IMO. X-Ray film is also giving way to digital, so availability for this product is also dicey.
http://www.ultrafineonline.com/ulcotodufi.html