A gobo is a template or pattern cut into a circular plate or lasered used to create patterns of projected light. The name may be derived from go between, or from Goes Before Optics. Go between refers to its position between the lamp and the lens. Another origin may be: Graphical optical blackout.
Glass gobos can include colored areas (much like stained glass windows), made of multiple layers of dichroic glass, one for each color glued on an aluminium or chrome coated black and white gobo. New technologies make it possible to turn a color photo into a glass gobo.
