  The STECF Calibration Enhancement effort for the Space Telescope Imaging
Spectrograph (STIS) aims to improve data calibration via the application of
physical modelling techniques. As part of this effort we have developed a model
of the STIS CCD readout process. The model itself is described in some detail
in earlier ISRs. Here we consider the application to STIS photometric data. We
demonstrate that this approach can successfully remove the trails typically
seen in CTE affected data and go on to ask whether this charge is being
restored to the cores of detected objects in the correct quantities. We find
good agreement between the simulation derived corrections and empirical
corrections for a range of background and source levels. Moreover we find that,
where the two differ, it is because only the simulation properly accounts for
the charge distribution in the array.
