Dell E1916HV 19" 16:9 LCD Monitor - Manual (Page 26)

26 Operating the Monitor
Brightness Allows you to adjust the brightness or luminance of the
backlight.
Press the key to increase brightness and press the key 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 key to increase contrast and press the key to
decrease contrast (min 0 ~ max 100).