Noun
(uncountable) The artistic technique of moving a light source to selectively illuminate parts of the subject or scene a camera is recording (at a slow shutter speed), or to shine directly into the camera and in this way sketch.
(uncountable) Camera painting, the artistic technique of moving a camera (while it records at a low shutter speed) such that light sources appear in multiple places or as streaks in the resulting photograph, the "painting".
(countable) A painting created using one of these techniques.
Used other than figuratively or idiomatically: see light, painting.
Source: en.wiktionary.org