Gobo (lighting)
[5][7] It may be an American slang abbreviation of "go-between",[1] or "go-before" (just as New York's "SoHo" signifies the area "South of Houston Street").
[11][12] The term gobo has been adopted in the recording industry to refer to a screen or sheet of sound-absorbent material that shields a microphone from sounds coming from a particular direction.
[4] Use of gobos augments light-shaping devices attached to the lights themselves, whether continuous or flash, with cones, snoots, honeycomb grids or barn doors being the most common such fittings.
[17] For long shoots on complex sets in the studio more convenient and precise are free-standing boards,[18] often configured as self-supporting hinged door-height panels (usually called "flats"), or if smaller, as a "flag", or a "dot" (a round flag), or a "finger" (larger and rectangular in form) attached to stands, or extending from arms or clamps attached to the tabletop for still-life and product shots.
[22] The photographer on location might use their lens hood, hand or dark slide for such purpose, but with multiple light sources in the studio a range of separate operable gobos provides tailored solutions.
Simple gobos, incorporated into automated lighting systems, are popular at nightclubs and other musical venues to create moving shapes.
Placement in "the gate" or at the "point of focus" is important because it produces a crisp, sharp-edged pattern or design (of logos, fine detail, architecture, etc.).
Gobos placed after the optics do not produce a finely focused image, and are more precisely called "flags" or "cucoloris" ("cookies").
However, in a "traditional" (tungsten-halogen) light fixture, the focus point position of a gobo is extremely hot, so these thin plastic films require special cooling elements to prevent melting.
A lapse in the cooling apparatus, even for seconds, can ruin a plastic gobo in a tungsten-halogen lighting instrument.
Lighting technicians can also hand-cut custom gobos out of sheet metal stock, or even aluminum pie pans.
The gobo is placed in the focal plane of the lantern (generally an ellipsoidal reflector spotlight or a moving head).
