LG UltraGear 27GL85 Owner's Manual page 27

Black Level
Picture Adjust
DFC
Picture Reset
Sets the offset level (for HDMI only).
y Offset: as a reference for a video signal, this is the darkest color the monitor can display.
High Keeps the current contrast ratio of the screen.
Low Lowers the black levels and raises the white levels from the current contrast ratio of the screen.
On Adjusts the brightness automatically according to the screen.
Off Disables the DFC feature.
Returns picture and color to the default settings.
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