XP2 SUPER film has a speed rating of
ISO 400/27° (400ASA, 27DIN, EI 400/27) to
daylight. The ISO speed rating was measured
using standard C41 processing. Although rated at
ISO 400/27°, XP2 SUPER can be exposed over the
range EI 50/18–800/30. When higher speed is
needed, XP2 SUPER can be rated at up to
EI 800/30. For finer grain, when speed is less
important, rate the film at EI 200/24, although for
finest grain it can be rated as low as EI 50/18 if
required.
The practical implications of this wide exposure
range are very important. XP2 SUPER can be
exposed at a setting to suit the job. The benefit of
variable speed also provides security against
inadvertent over- or underexposure.
It should be noted that the exposure index (EI)
recommended for XP2 SUPER is based on a
practical evaluation of film speed and is not based
on foot speed, as is the ISO standard