Gobo (lighting)

A gobo (Graphical optical blackout) is a mask (originally made ​​of metal, now often made ​​of glass ) that is plugged into a spotlight or projector to show on stage or for advertising purposes logos, designs, text, or images. The presentation takes place similar to a slide projection or with simpler devices as shadow projection.

The advantage of this technique is the heat resistance of the gobos. Previously, these were cut from thin sheet metal. Certain forms (for example, the letter "O") could not thereby be displayed perfectly. Therefore Blechgobos were replaced by glass panels. These are provided with a chromium layer, which is then partially removed by etching or by a laser. To allow colorful displays that the chromium layer is combined with dichroic color filters.