Gobo’s and Effect Projection
A Gobo is a piece of metal (or in some cases, glass) which can be placed inside some lights to block out parts of the light. This sillouette is projected as a shape of light and so allows patterns of light to be formed. Many hundreds of Gobo’s are available in standard patterns, logos, text and shapes and they can also be custom produced if required.
Most standard Gobo’s are cut from thing sheets of metal as this is inexpensive and easily mass produced. Glass Gobo’s are normally reserved for applications that require spot colour and picture details that would not be feasible through the cut out of metal.
Gobo’s are mainly used in Profiles such as an ETC Source 4 as they provide very fine control of the light output, through the use of shutters and lenses. Gobo’s are also found in many moving lights, usually 8 + open Gobo’s are used as this allows for on the fly choosing of a Gobo and allows a designer to use one light source for many different effects. Many (more expensive) moving lights include 2 Gobo Wheels as well as the option to rotate individual Gobo’s.
Generic Effects Projection is a way of creating effects like Rain, Fire, Water, and others by using nothing but generic lanterns and Gobo’s with either an Animator or Rotator. Most Effects can be created using a Profile, Gobo and Gobo Rotator, for example Rain can be produced with a ETC Source 4, Rain / Breakup Gobo and a Rotator, you might think that the rain will be going wound in circles rather than the standard down. Using clever shuttering in the Source 4 you can only limit the output to the direction you wish your rain to go.
Fire is slightly harder to make using just a Gobo and Rotator, this where animators come in, they take a special type of Gobo, which is again rotated but the effect that ids given off is more of a flicker than a rotation.
Profiles, Gobo’s and Rotators are not the only way’s to project Effects, there are also dedicated Effects Projectors such as Patt 252 with Animation Wheel. These how ever are allot heavier to rig, and require the correct focal lenses to work. Recommend uses if you want to cover a large are in a particular effect, again for example rain across the whole set and cyc.