Gobos can be made from various materials. The most common types are made of metal and glass.
Metal gobos are using a metal template from which the image is cut out of. These types of gobos are the most sought of the common gobo types but often require modifications to the original design called “bridging” in order to display correctly. Steel gobos quickly limit the quality of many designs. For example, letters like A, O, R, P, Q, B, 4, 6,8, 9 need to include some tabs/ bridges to form the letters correctly and to hold the design in place.
Metal gobos are the most durable of all gobo templates and are most appropriate for theatrical applications and where this template will be used often in extreme conditions.
Glass gobos are made from transparent glass with a partial mirror coating to block the light and produce “black” areas in the projected image. This eliminates any need for tabbing/ bridging, since the glass itself is the support and allows more various images to be produced. Glass gobos can also include colored areas, whether by multiple layers of dichroic glass (one for each color) glued on an aluminium or chrome coated black and white gobo, or by newer technologies that allow the thickness of the dichroic coating which is varied in a controlled way on a single piece of glass, making it possible to turn a color photo into a glass gobo. Glass gobos generally offer the highest image fidelity, revealing for the projection of full color photos and very detailed images where color and color accuracy is important, but they are the most fragile. Usually, to create a glass gobo laser ablation or photo etching is used.