Push / Pull from box ISO
One-tap chips to rate a loaded film at +1, +2, -1, or -2 stops from its box speed.
Where to find it
ISO modal (tap the ISO dial center) inside Film Stock mode, a Push Pull chip row appears under the film picker.
Summary
Push/pull row in the ISO modal that shifts the loaded film's box ISO by a discrete number of stops. The dial widens to render the shooting ISO (e.g. TMAX 400 at +1 = ISO 800); a small badge on the main viewfinder shows the active push/pull state; the Development Advisor folds the push into its N+/N- recommendation; profile presets persist the override across reboots.
How it works
Push/pull is the classic darkroom workflow: load Tri-X 400, set the meter to ISO 800, expose the whole roll at that shooting speed, then develop longer to compensate. You get one more stop of speed in available-light scenes at the cost of a bit more grain and contrast. Pulling is the reverse: rate the film slower, expose for more shadow detail, develop less to keep highlights from blowing out.
How to use it
Tap the centre of the ISO dial to open the ISO modal. With a film loaded in Film Stock mode, you'll see a row of chips: -2, -1, Box, +1, +2. Tap +1 to push by one stop (TMAX 400 becomes ISO 800), tap -1 to pull by one stop, tap Box to clear the override. The dial on the main screen updates immediately to show the shooting ISO.
Push/Pull badge
When a push or pull is active, a small pill appears just below the FMT/EV/ISO dial row on the main viewfinder: "PUSH +1 · ISO 800" or "PULL -1 · ISO 200". Cyan for push, warm tone for pull. Tap the badge to jump back into the ISO modal.
Development Advisor pairing
Open the Development Advisor (5.x) with a push active and it shows a breakdown: 'From contrast' (the N+/N- that SBR vs film latitude suggests) and 'From push/pull' (the stops you dialled). The headline 'Development' line is the sum — so SBR says N-1 and you pushed +1 means net N (no extra dev time), but SBR says N and you pushed +1 means develop for N+1.
Expired-film label
Expired-film decay scales with the film's box ISO (silver grains age regardless of how you meter), but the displayed ISO line in the Expired Film calculator now shows both: 'TMAX 400 (B&W negative, ISO 800 (box 400))' when push is active, so you can sanity-check what the calculator is computing against.
Persists per profile
The push/pull override is part of the Profile snapshot, so it persists across app close and reopen, and switching profiles applies that profile's push state. The profile summary line shows '(+1)' after the ISO when a push is baked in, so you can tell at a glance which of your profiles is pre-set to push.
Limits
Chips cover -2 to +2 stops, which is the practical range for normal silver B&W and modern color neg. For finer-grained pushes (eg +0.7), use the Custom ISO field directly — the badge will show '+0.7' and the dial will render the exact value. For pushes beyond ±2 stops, the same Custom ISO field handles arbitrary values, but expect significant grain and shadow loss.