Many Home Fleet ships were painted medium gray during 1939 and 1940 to decrease visibility from the peacetime dark gray.

The previous alert, issued last week, simply advised military personnel to "decrease visibility" because "some civil disturbance activity is probable."

The almost solid wall of wind-stripped water decreased visibility to less than three hundred yards.

Fog decreases visibility, which results in the Union matrix being smaller, enemy units' manpower becoming indiscernible in battle, and a high chance of units going into Panic when hit with an enemy charge.

Linear polarizing filters decrease visibility underwater by limiting ambient light and dimming artificial light sources.

The cloud cover made the terrain gloomy, and the falling snow decreased visibility dramatically.

The haze decreased visibility in satellite images too.

Observing in the infrared is also hampered unless the detector is refrigerated, since the heat of the instrument creates a glow that decreases visibility.