Film Reciprocity Tables

June 2015

Overview

Film sensitivity to light is not linear. This means that as an exposure time increases, the film is less sensitive. So to get a proper exposure, you need even more time. This is called film reciprocity.

The Reciprocity Charts below show the adjustments that should be made for different film types–each film has different sensitivity.

An example using the chart, if the indicated light meter or estimated time is 1 minute for Kodak Tri-X, the adjusted exposure should be 8 mins.

My Exposure Calculator web app is one way of estimating exposures, light meters don’t work too well at night. You can see my Night Photography for examples of my work.

Charts

Table 1: Films: Fuji 64T, Fuji Velvia

Indicated:	4s	8s	10s	16s	20s	30s	40s	1m	2m	4m	6m	10m	15m	20m	30m	1 hr
Adjusted:	5s	12s	16s	28s	39s	1m	1m 28s	2m 30s	4m 50s	10m	15m	25m	37m	50m	1m 14m	2 hr 30m

Table 2: Films: Kodak Tri-X, Kodak Plus-X

Indicated:	2s	3s	4s	8s	10s	15s	20s	30s	40s	1m	2m	3m	4m	6m	10m	15m	20m	30m	1 hr
Adjusted:	4s	8s	12s	36s	50s	1m 35s	2m	3m 30s	4m 40s	8m	18m	25m	40m	1 hr	2 hr	3 hr 20m	4 hr	6 hr 20m	12hr 30m

Table 3: Films: Kodak 160t

Indicated:	4s	8s	16s	30s	1m	1m 30s	2m	3m	4m	6m	8m	12m	16m	30m	1 hr
Adjusted:	5s	12s	26s	54s	2m 6s	3m 26s	5m	8m	11m 22s	18m 39s	26m 29s	43m	1 hr	2 hr	3hr 50m

Table 4: Films: Kodak T-MAX

Indicated:	2s	5s	10s	15s	20s	30s	1m	2m	4m	10m	20m	1 hr
Adjusted:	3s	7s	15s	25s	35s	50s	2m	4m 30s	10m	30m	1 hr 10m	3 hr

Table 5: Films: Ilford HP5, Ilford FP4

Indicated:	5s	10s	15s	20s	25s	30s	1m	2m	4m	6m	10m	20m	1 hr
Adjusted:	13s	31s	55s	1m 23s	1m 57s	2m 35s	7m 8s	17m 21s	36m	55m	1hr 32m	3 hr	9hr 20m

Table 6: Films: Fuji Provia 100F

Indicated:	2m	5m 20s	6m 40s	8m 20s	10m 40s	13m 20s	16m 40s	21m
Adjusted:	2m	5m 32s	7m 10s	9m 30s	13m 31s	19m 27s	29m 33s	50m

Sources

Table 1 Velvia data from Michael Davis. Fuji 64T equivalence from Olympus Reciprocity Table
Table 2 Tri-X data from The Nocturnes, includes Kodak Plus-X equivalence from Kodak reciprocity data sheets.
Table 3 Kodak 160T data from Lunar Light
Table 4 T-MAX data from The Nocturnes
Table 5 Ilford FP4 and HP5 data from Ilford Data Sheets and HueCandela.com [pdf] data was not available for the higher indicated exposure values, the adjusted values were extrapolated out.
Table 6 Fuji Provia 100F data from Lunar Light