Metrochrome

Metrochrome is a darkroom in your pocket. Load a roll, expose it, develop it, and print from it — on film that is measured rather than imagined. EVERY EMULSION IS A MEASUREMENT Thirty-six colour and black-and-white stocks, each carrying its own spectral sensitivity, characteristic curve, dye density and grain structure, digitised from the manufacturers' published datasheets. Nothing here is a preset with a film's name on it. The same curves the renderer samples are the ones plotted on each film's datasheet page in the app — they cannot disagree, and that is the point. A NEGATIVE, THEN A PRINT Your photograph is exposed onto the emulsion, developed, and then printed: through a colour paper for a colour negative, or onto Ilford Multigrade for a silver one. Grain sits in the density domain where it belongs, scaled to the film size you chose — a 110 negative is coarser than a 4×5 because it is. Halation is the film's own, measured per layer and applied across the whole frame rather than traced around bright edges. DARKROOM INSTRUMENTS, NOT SLIDERS • Enlarger head — cyan, magenta and yellow filtration in printing points • Ring-around — nine filter packs side by side, because a cast cannot be judged on its own • Test strip — three exposures a half-stop apart, to choose the time by • Timer and paper grade — how long the paper is exposed, and how hard it is • Dodge and burn — marks laid on the print and stepped ±2 stops by hand • Step wedge — eleven patches, per channel on colour film • Lens filters — yellow, orange, red and green for black and white, from the published transmittance tables • Development — a developer and a time from the maker's own curves, with a clip test to choose between them • Film size — 110 to 4×5, which changes the grain because it changes the enlargement THE ROLL IS THE UNIT A film is a decision for a whole roll, not a filter for one picture. Expose frames, choose the emulsion, develop, and every frame is read on it at once. Nothing is fixed until you develop, and a roll can be developed again on another film whenever you like. WHAT IT COSTS Every film is free, and stays free. The Metrochrome Pass is one payment that unlocks the printing instruments above, on your Apple ID, on every device signed in to it — including the tools added later. There is no subscription. YOUR PHOTOGRAPHS STAY YOURS Everything happens on the device. No account, no advertising identifiers, no tracking. Frames are read from your library, processed here, and written back only when you export them. Anonymous crash reports and usage statistics can be turned off in Settings → Privacy. All film names are trademarks of their respective owners. No manufacturer endorses, sponsors or is affiliated with this app. The emulations are interpretations built from published measurements, not reproductions.