Dell S2740L User Manual page 32

Brightness Brightness adjusts the luminance of the backlight.
Press the button to increase the brightness and press the
NOTE: Manual adjustment of Brightness is disabled when Energy Smart or Dynamic Contrast is switched On.
Contrast Adjust the Brightness first, and then adjust the Contrast only if further adjustment is necessary.
Press the button to increase the contrast and press the
The Contrast function adjusts the degree of difference between darkness and lightness on the monitor screen.
Auto Adjust Even though your computer recognizes your monitor on startup, the Auto Adjustment function optimizes the display settings for use with your particular setup.
Auto Adjustment allows the monitor to self-adjust to the incoming video signal. After using Auto Adjustment, you can further tune your monitor by using the Pixel Clock
(Coarse) and Phase (Fine) controls under Display Settings.
button to decrease the brightness (min 0 / max 100).
button to decrease the contrast (min 0 / max 100).