G-bar

Definition: Average gradient of the mid-tone portion of a characteristic curve. * Slope of the line joining the two defined points -- usually from the usable density above shadow to the usable density below highlight. * Usually resorted to when there is no obvious straight-line portion to the characteristic. * Also known as contrast index.

Related Terms: gamma

Previous Term: Gaussian optics  Next Term: GCR

Type a photography term below to find its definition: