Dell E2213H Monitor - Manual (Page 23)

Brightness Allows you to adjust the brightness or luminance of the backlight.
Press the button to increase brightness and press the button to decrease brightness (min 0 ~ max 100).
Contrast Allows you to adjust the contrast or the degree of difference between darkness and lightness on the monitor screen. Adjust brightness first,
and adjust contrast only if you need further adjustment.
Press the button to increase contrast and press the button to decrease contrast (min 0 ~ max 100).
Auto Adjust Use this button to activate automatic setup and adjust menu. The following dialog appears on a black screen as the monitor self-adjusts to
the current input: