Utilization of non-printing high-spatial-frequency auxiliary pixels are
introduced into the bitmap of halftones utilized in an image to obtain local control
of the image development by modification of local average voltage in the development
nip. These auxiliary pixels embody frequencies or levels of charge that are past
the threshold for printing on the Modulation Transfer Function (MTF) curve, and
therefore by themselves result in no toner deposition on the resultant page. These
auxiliary pixels will however, position the toner cloud by modulating it and compensate
for cleaning field and toner supply effects. This will better position the toner
cloud to ensure adequate toner supply to all parts of the image so that the desired
printing pixels will print as intended and provide a more faithful rendering of
grayscale information in the image.