Fujifilm · ISO 100 B&W negative
Fujifilm Acros 100 (original)
The original Acros 100 had one property that set it apart from every other continuous-tone black-and-white film ever made: reciprocity failure was almost nonexistent. Fujifilm's Schwarzschild coefficient for the original emulsion came in below 1.0 in most published tests, meaning long exposures at the negative matched metered times with almost no correction. Astrophotographers, night-cityscape shooters, and anyone who regularly put the camera on a tripod for exposures longer than a few seconds built entire workflows around this behavior.
The way this played out in practice: a meter reading of 60 seconds was 60 seconds at the negative, or close enough that the difference was absorbed by exposure latitude. Other films at 60 seconds can need double that time after correction. Acros users working in the dark did not need to carry reciprocity tables or run mental arithmetic. They metered, set the timer, and trusted the film.
The tabular grain structure also made it one of the finest-grained ISO 100 films available. Zone System workers loved the combination: fine grain for large prints, a long and well-articulated midtone curve, and the ability to shoot multi-minute exposures without the exposure math becoming the limiting variable in the process.
Fujifilm announced discontinuation in 2018, citing the difficulty of sourcing specific emulsion components. The film community did not take it quietly. Threads on large-format photography forums filled with freezer stock announcements and calls to Fujifilm's corporate office. The 2019 replacement, Acros II, with emulsion still made at Fujifilm's Ashigara plant in Japan and final coating handled by Harman in the UK, restored most of the reciprocity behavior that made the original famous. Zone Light Meter applies the reciprocity correction past one second for Acros II as it did for the original, though in both cases the correction is unusually small.
Original Acros 100 stock from frozen inventory still circulates. Test older rolls carefully before committing them to important work.
How the app handles this stock
- Box speed: ISO 100. Picker exposes pull/push chips so you can shoot it at any speed you want and the meter follows.
- Reciprocity: No reciprocity correction needed; metered time is the shot time.
- Expired film: if you load an old roll, set the expiry year and storage in the app and the ISO scales for you. B&W negative decay rates are baked in.