Definitions for "Contrast Control"
The manner in which the display contrast is controlled. Most terminals allow manual control, where the software allows the operator to adjust the contrast while viewing the display. Better terminals also have automatic temperature-based control (temperature compensation), which keeps the contrast from varying as the ambient temperature varies.
A control in a monitor that changes contrasts by increasing or decreasing amplitude of video signal
Is a feature of many video monitors. This allows the user to manually adjust the screen contrast for better picture visibility. Contrast Ratio is a monitor specification. This number indicates the dynamic range of brightness (difference between darkest and brightest) a monitor is capable of displaying.
Keywords:  darken, faint, lighten, optimum, darker
The ability to adjust for light or dark originals for optimum image quality. If, for example, a document has a darker background than normal, or the writing is faint, you simply adjust the contrast to either lighten or darken the image. Contrast can be adjusted when copying or faxing.