Dell UltraScan P990 User Manual page 19

Before you can adjust this setting, the Cancel Moire setting must be turned on.
Select the CANCEL MOIRE menu to turn on the Moire
Adjustment.
To adjust the amount of moire cancellation, first press
m/M buttons to highlight
the
Then press the 6 </, buttons to adjust the amount
of moire cancellation until the moire effect is at a
minimum.
(MOIRE ADJUST).
OPTION
OFF ON
CANCEL MOIRE
OPTION
26
MOIRE ADJUST
Using the Monitor 1-11