Reciprocity calculator
Reciprocity failure calculator
Beyond roughly one second, film loses effective speed. Pick a film family and your metered time to get the corrected shutter and the compensation in stops.
Corrected shutter—
Compensation—
Or compensate with aperture—
Results past 100s are linear extrapolations — bracket and test.
Common reference values (stops)
| Film family | 1s | 10s | 100s |
|---|---|---|---|
| Kodak Portra 160 / 400 / 800 | +0 | +0.33 | +1 |
| Kodak Ektar 100 | +0.33 | +0.5 | +1 |
| Kodak Gold / ColorPlus 200 | +0.33 | +1 | +2 |
| Kodak UltraMax 400 | +0.33 | +1 | +2 |
| Fujifilm C200 / Superia / Fujicolor | +0.33 | +1 | +2 |
| Slide: Provia / Velvia / Ektachrome | +0.33 | +0.5 | +1 |
| Ilford HP5 / FP4 / Delta | +0.5 | +1 | +2 |
| Kodak Tri-X / T-Max | +0.5 | +1 | +2 |
| Cinema: CineStill 800T / Vision3 | +0.33 | +1 | +2 |
| Budget B&W: Fomapan / Kentmere / GP3 | +0.5 | +1.5 | +2.5 |
Compiled from manufacturer data and community practice as a starting point. Batch, processing, metering and filters all shift the result.