
Add Emotion and Visual Interest to a Scene
Any great set designer will tell you that when lighting a scene, the lights you use are only part of the equation. Like any great art, what you leave out is just as important as what you put in. Enter: gobos. Derived from the phrase “GOes Before Optics”, gobos fit between your light source and lens to partly obscure or modulate light.
View the Rosco Gobo catalog (PDF) or use Rosco’s iPhone app for gobos to see a sample of the styles and colors available. Don’t forget to find a dealer once you’ve picked a few out!

Types of Gobos
Depending on what they’re used for, gobos may be made of stainless steel or glass. Stainless steel gobos selectively block light, often creating a stippled effect or more or less expressionistic shapes.
Glass gobos come in a variety of forms:
Colorizers create beautiful multi-colored effects. Image Glass gobos are colorless, bending and refracting light to create complexity. Prismatics are usually fitted into moving lights and project kaleidoscopic patterns.
ColorWaves create vivid dichroic color patterns such as waves and mosaics. Different gobos can be used on each light and mixed on-stage to liven things up.
Usually, you’ll need a gobo holder for each of your gobos, although some holders can accept multiple gobos in series. And gobos can be used like cogs — placed into a motorized gobo rotator, which can turn the gobo at various speeds for even more interesting displays.

Gobo Sizes
It’s important to understand that gobos come in a variety of sizes. Depending on the lamp you use, you will want compatible gobos and at least one compatible gobo holder.
Standard Gobo Sizes (Measurements in millimeters)
Letter Size |
Outer
Diameter |
Artwork
Diameter |
Comments |
A Size |
100 |
75 |
|
B Size |
86 |
64.5 |
|
M Size |
66 |
48 |
|
E Size |
37.5 |
28 |
|
BG Size |
79 |
64.5 |
Obsolete glass size. Available by special order. |
C Size |
150 |
120 |
C Size available size by special order. |
G Size |
65.5 |
48 |
For Clay Paky Goldenscans |
D Size |
53.3 |
38 |
|
Cyberlight |
44.25 |
38 |
|
Studio Spot 575 |
36.3 |
31 |
For HES Studio Spot 575 |
Mac 500/918 |
27.5 |
22 |
Not all standard designs available in this size. |
V Size |
25.5 |
22 |
Not all standard designs available in this size. |
Mac 250 |
22.5 |
17 |
Not all standard designs available in this size. |
518 Size |
20 |
13 |
Not all standard designs available in this size. |
Sizes listed in millimeters. Not all designs are available in all sizes. Please call to verify availability. |
Custom Gobo Designs
One of the coolest things about gobos is that you can make your own custom designs! We can accept artwork from you or your graphic designer and match it to almost any gobo size you need. Prices and turnaround time are very reasonable — simply email us to get the ball rolling.
Need Advice?
If you’re feeling overwhelmed, don’t worry — we can help. Get in touch and we’ll be happy to explain your options, or refer you to a knowledgeable dealer in your area.