Ricoh AP204 Operator's Manual page 13

Brightness
This setting controls the overall brightness of the image. Moving the slider to
the plus (+) side increase brightness, while moving it to the minus (-) side
decreases brightness.
-30
Contrast
This setting controls the range between the darkest and lightest shade of an
image. Moving the slider to the plus (+) side decreases the range and makes
contrast stronger, while moving it to the minus (-) side expands the range.
-30
Saturation
This setting controls the purity of a color. Moving the slider to the plus (+)
side increases saturation and makes colors more vivid, while moving it to the
minus (-) side decreases saturation.
-30
x
0
0
0
+30
+30
+30