The factors contributing to possible errors in the measurement of diffraction intensities are summarised below along with estimates of the size of errors.
The calibration image formed by illumination with a uniform flood field
typically displays variations in sensitivity of about 
due to
inhomogeneities and imperfections in the plate surface. Use of the image file
as a correction to subsequently measured flood field images demonstrated that
this correction procedure introduced an uncertainty which was on average much
less than the statistical noise in the data.
The intrinsic noise of the image plate scanner as measured by the
manufacturers is 
ADC units. (One ADC unit is approximately equivalent
to one absorbed photon.) This value is very small when compared to the dynamic
ranges of the detectors, 
for the MAR scanner and 
for the
RED scanner. The dynamic range of the image plate scanners are limited by the number of bits used
by the ADC unit.
The X-ray absorption efficiency of the 
phosphor is 
for X-ray energies
below 
and falls off to only 
with 
photons.
The linearity of the image plate phosphor has been measured by Amemiya et al [2]
for X-rays over six orders of magnitude. The response was found to be linear to within a relative error
of 0.05 over the range from 8 to 
photons/pixel. At higher levels of exposure however the
measured intensity falls off gradually. The response is however linear within the dynamic range of the
detectors.