schwarzschild all nur zeiten .pdf

Schwarzschild effect compensation
for different photographic materials
For most photographic materials, reciprocity is valid with good accuracy over a range of values
of exposure duration, but becomes increasingly inaccurate as we depart from this range: the
Schwarzschild effect. As the light level decreases out of the reciprocity range, the increase in
duration, and hence of total exposure, required to produce an equivalent response becomes
higher than the formula states; for instance, at half of the light required for a normal exposure,
the duration must be more than doubled for the same result. (http://en.wikipedia.org/wiki/
Reciprocity)

corrected exposure time [sec]

10000

1000

100

10

1

Tmax 100
Tmax 400
NEOPAN
1

10

Ilford
TriX 400
BW400CN
AGFA APX
ADOX CHS
Fomapan 100
Fomapan 200
Fomapan 400

100

1000

measured exposure time [sec]
Figure 1: Corrected exposure time values to compensate the Schwarzschildeffect for different
photographic materials

Data aquired by ILFORD, FUJIFILM, KODAK,
ADOX and FOMA photo fact sheets and websites
licensed under creative commons cc-by-nd
www.flickr.com/lennox_mcdough