Dell P1911 Monitor - Manual (Page 18)

Submenus
Energy Gauge This meter shows the energy level being consumed by the monitor in real time. When the meter is green, it indicates the monitor is
consuming low energy level. When the energy consumed increases, the meter will change to yellow and subsequently red.
Brightness/Contrast Use this menu to activate Brightness/Contrast adjustment.
Brightness Brightness adjusts the luminance of the backlight.
Press the button to increase brightness and Press the button to decrease brightness (min 0 ~ max 100).
NOTE: Brightness control will be greyed out during "Screen dim" in PowerNap option when screen saver is activated.
Contrast Adjust Brightness first, and then adjust Contrast only if further adjustment is necessary.
Press the button to increase contrast and Press the button to decrease contrast (min 0 ~ max 100).
The Contrast function adjusts the degree of difference between darkness and lightness on the monitor screen.