A blackout is a kind of joke in broad, fast-fire slapstick comedy. The term is derived from burlesque and vaudeville , when the lights are quickly turned over to the punchline of a joke to accentuate it and / or allow for audience laughter. It can be used as a joke, and it can not be initially noticeable to all viewers if it is a very fast joke.
It is distinguished from an iris shot , frequently used in the silent film era, where a black circle closed to a scene.
The term “blackout gag” can also apply to fast-paced TV or movie comedy, such as Rowan & Martin’s Laugh-In , where there may not be a blackout, but a quick cut to the next gag.