A part of that batch are ORWO films, from the former DDR, which had expired between 1966 and 1969.
The NP10 film turned out to be quite rare, nothing on how to shoot it or how to develop it. Time for an experiment i'd say!
After asking around and reading about developing methods for very old film i decided to go for a somewhat unconventional way called the "hard, fast and cold" method. The writer of that piece had succesfully developed old films this way but there was no strict how-to available.
So i just followed my own thoughts combined with the knowledge i read about and my own experience and mixed a HC110 dilution B at 18 degrees C in which i would soup the test strip for 5 minutes with an almost continously agitation.
The results blew me of my socks! What a great film is this!
Here's the set-up i used for the teststrip: Minolta SRT303 with Rokkor 1.7/85, measured light with Minolta Autometer III.
The test strip, four shots ranging from ISO4 to ISO10. Boxspeed of this film is DIN10 (hence the NP10 name) which corresponds with ISO8. Incredible but true: this gave the best result!! To give you an idea of ISO 4 in full sunlight afternoon, that is 1/8 of a second at f/5.6!
And here's the winner, a large picture of the NP10 shot at boxspeed, imagine that, it really has expired in 1967!!!