Gobos are discs put into lighting fixtures that project patterns. They block out light to create specific designs and effects. These projected patterns are commonly used to add texture to a lighting design in theater, but also have lots of applications in the events world as you can project specific logos or images. You’ll see them a lot in wedding receptions or corporate events.
The snowflakes projected on this drop are from a gobo like the one on the right side.
How does a gobo work, exactly?
A gobo is inserted upside down and backwards in the body of a lighting instrument. This places the gobo between the light source and the lens. This might also where we got the term gobo. It goes between (go-bo) the light source and the lens. If the fixture has no lens, it is impossible to focus the pattern made by the gobo without moving the lighting instrument, which is too impractical for most applications. With a gobo, focus is key. The light comes from the lamp or diode and hits the gobo, which blocks out all of the light except for the desired pattern. The light then hits the lens, which flips the image back around to the correct orientation so it will appear as desired on a wall or floor.
Types of Gobos:
Steel gobos are the most common type of gobos and the most affordable. They are thin pieces of stainless steel that have patterns cut into them, making them stencils for light. Because they are stencils, the designs on steel gobos must always be one solid piece of metal. For that reason, some custom designs end up modified to match that stencil format.
Here the letters “e,” “a,” “d,” and “o” all have lines cut into them so that the metal will be one piece. The white in this image represents the holes cut into the steel. The tabs hold the inside of the letters in place and keep them legible. Notice the pattern around the edge can still be very intricate, but the black area must always be connected. This stenciling process is important to consider when you design a steel gobo. You don’t want a design that will need too much editing. That is in contrast to…
Gobo Types- Glass
Glass gobos are also available from Rosco and Apollo and available in one, color, two colors, or full color. They are different from steel not just that they are made of glass, but that they form one solid disc. There is nothing cut out. Instead the glass is built layer by layer to form the pattern desired. Because of that level of control, these gobos can be photorealistic if needed.
Note the solid lettering, which is possible in glass gobos. Glass gobos are made by layering glass into a solid disc. By making the glass layers different colors, photo-real images can be printed in color, as in the image above. Glass gobos also last longer than steel gobos in incandescent fixtures as steel can warp from the heat of a conventional fixture. Glass gobos have a longer lead time and a higher price point than steel gobos. If you have the time before your event and are looking to re-use the gobo it can be well worth the investment.
Gobo Size and Holders
Gobo size is represented as a letter or by two numbers. The letters are A, B, E, and M. These are shorthand for gobo sizes that are used by a wide variety of instruments. Exact specifications of these standards can vary slightly depending on the fixture manufacturer, so always know who made your lighting instrument. Any gobo needed that isn’t one of these sizes can be specified by the Outside Diameter (OD) and the Inside Diameter (ID), both measured in mm. The OD is the actual diameter of the gobo, the ID or Image Size is the diameter of the space available for the gobo’s design. This is the only part of the gobo that light will hit, the rest will be gripped by the gobo holder to make sure the gobo is secure in the light fixture.
Each instrument that can accept a gobo will have a gobo holder sized specifically for the instrument. Always double check that you have the correct gobo or pattern holder for the instrument you are using and the gobo you are ordering. Glass and steel gobos also need different holders as glass gobos are much thicker. Not every lighting fixture is sold with a pattern holder and some fixtures can even take multiple gobo sizes depending on the holder you have (usually an A or a B size.) Verifying that your instrument, pattern holder, and gobo are all sized to work together will save a lot of headaches down the line as custom gobos are not returnable items.
How do I order?
Custom steel gobos are usually between $65.00 and $90.00, Glass gobos range between $200.00 and $600.00 depending on the number of colors needed. Size usually doesn’t affect the pricing on gobos, though some moving head fixtures’ gobos are so small they are discounted. Before you order, remember:
-Glass gobos are the most durable and can match a design exactly, including color. They are solid pieces of layered glass. Glass gobos have a lead time of 2-5 business days depending on the complexity of design.
-Steel gobos are stencils (holes cut out of a thin metal disc) and the manufacturer will sometimes need to alter a design slightly to make it into a stencil (particularly with lettering). They have a lead time of 1 business day.
To order a custom gobo we’ll need the following.
- A digital copy of the artwork (all file types accepted; vector file types guarantee no image resolution issues)
- The size of gobo you need. If you don’t know the size, we can get that information if we know the make and model of the instrument projecting the image.
Always ask about a free digital proof if you are unsure of your design. A proof comes free with order payment from the gobo manufacturer. This will guarantee that a design matches what you want exactly. A proof will add an extra day of lead time to an order to make sure that there is enough time to get your approval on the artwork.
How can I order one?
You can always call our team in the retail store at 206-622-7850 and any available rep will be happy to help you. We can also be reached at firstname.lastname@example.org if you prefer to reach out via email.