How Expired Film compensation works
Stops over for film that has lost speed with age.
Where to find it
Tools tab Expired Film
Summary
Calculator for old film that has lost sensitivity with age. Turns the age and storage condition of your roll into a stops-over recommendation you can apply on the main wheel.
Detail
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How it works
Film loses sensitivity as it ages. Old rolls need extra exposure to record the same scene a fresh roll would handle at box speed. This modal turns the age and storage condition of your roll into a stops-over recommendation you can apply on the main wheel.
Age
How many years past the expiration date the roll is. Pre-expired film (still in date) needs no compensation.
Storage
How the roll was kept. Frozen film barely degrades, and a 30-year-old frozen roll can shoot at near box speed. Refrigerated keeps well too. Room temperature is the standard rule of thumb. Hot or sunny storage (a glove box, a windowsill) accelerates the loss substantially.
Rule of thumb
The classic rule is plus one stop per decade past expiration for film stored at room temperature. Frozen storage is roughly half that. Hot storage roughly doubles it. Color film loses speed faster than black and white, especially in the magenta layer, which is why old color rolls often shoot warm or muddy.
Master switch
There is a separate toggle that decides whether the compensation is actually fed to the exposure solver. Useful when you want to keep a roll's age configured without applying the push every time you meter.