Gain

Gain, also called brightness gain or luminance gain, is the measurement of the increase in brightness between the input and the output of an image intensifier tube.

Specification

There are two different ways of specifying gain.

Imperial

Gain specified in imperial units uses the units of foot-Lamberts by foot-candle (${\textstyle \mathrm {fL} /\mathrm {fc} }$).

To measure gain in accordance to the MX-10160/AVS-6 specification, the photocathode is exposed to $2*10^{-6}\mathrm {fc}$. A photometer is then used to measure the brightness of the phosphor screen (in $\mathrm {fL}$). The resulting value is divided by $2*10^{-6}$ to obtain the gain in ${\textstyle \mathrm {fL} /\mathrm {fc} }$.

To further test auto brightness control, the same procedure