Reciprocity

Kentmere Pan 400 long exposures

What a metered time becomes on Pan 400, and the stops it adds — worked out from Kentmere’s own data, never past it.

Form T-2

Your metered time

Tc = Tm^P for metered times over 1 s; 1 s or less needs no correction (P = 1.3)

The maker’s reciprocity data ↗

Table 1

At a glance

Metered	Expose for	Added
1 s	1 s	—
2 s	2.5 s	+0.3 stops
4 s	6.1 s	+0.6 stops
8 s	15 s	+0.9 stops
15 s	34 s	+1.2 stops
30 s	1 min 23 s	+1.5 stops
1 min	3 min 25 s	+1.8 stops
2 min	8 min 25 s	+2.1 stops
4 min	20 min 42 s	+2.4 stops
8 min	50 min 59 s	+2.7 stops
16 min	2 h 06 min	+3 stops

Other films with reciprocity data

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