Side by side differences in gobo sizes.
The gobo size that you need is based on the light fixture that will project that gobo. Many traditional theater style lights like a Source 4 ellipsoidal light or LEKO light will use a size B gobo (about the diameter of a coke can). Cheap DJ effect lights like the Chauvet Zoom or American DJ LED gobo projector use a custom gobo size that is about the size of a dime.
Why different gobo sizes?
It’s based on the the power of the light source.
More powerful light sources use bigger gobo sizes because there is more light to shoot through a larger template and the template needs more surface area to dissipate heat. Stronger light sources result in a brighter, bigger image but often comes at the expense of a larger sized light fixture.
Small cheap effect lights like the Chauvet Zoom, American DJ Gobo Projector LED are not recommended. These lights use teeny-tiny gobo templates to project with limiting detail and brightness. These lights may look good in a small dark bedroom or living room but don’t hold up to real life events of more than 30 people.
Example of a D-sized transparency gobo used at an event results in an extremely clear image.
Smaller gobo sizes mean there is less physical space to print detailed images. Smaller gobos are better suited for blockier, less detailed designs like the cross shape used in the smallest gobo in our example photo. More detailed designs like those used for weddings are better suited to larger gobo sizes (E-size or bigger).
When considering a gobo light this is what we recommend:
- E-Size or bigger gobo
- A light fixture that supports multiple lenses
- At least a 30w (LED) light source
Common gobo sizes
Here is a table of some popular standardized gobo sizes and common light fixtures that use those gobo sizes:
| Letter Size | O.D. (mm) | I.A. (mm) | Notes |
|---|---|---|---|
| A Size | 100 | 75 | |
| B Size | 86 | 64.5 | Standard Size for Ellipsoidal lights (Source 4, Source 4 Zoom) |
| M Size | 66 | 48 | Source 4 Jr. |
| G Size | 65.5 | 48 | For Clay Paky Goldenscans |
| D Size | 53.3 | 38 | Martin PR-1, LEDSpot 40 |
| E Size | 37.5 | 28 | LEDSpot 25, LEDSpot 30 |
| O.D = Outside Diameter; I.A. = Image Area | |||
The OD (Outer Diameter) number is the diameter of the actual template itself. The IA (Image Area) number is the useable are that can be used to print the image used for the gobo. It’s important to know these numbers when ordering a gobo, especially the IA. The IA can change from light fixture to light fixture even for commonly used gobo sizes. Make sure you know the OD and the IA of the gobo size for your particular lighting fixture you’ll be using for your event. Also know what types of gobos your light supports.
Gobo sizes compared showing a Chauvet Gobo Zoom 2.0 vs. the LED 40 lights Superlative Events uses.
Bottom Line
When ordering a gobo know the OD and the IA of the light fixture you’re using. Realize that larger gobo sizes can support higher levels of detail in the resulting image. Most corporate gobos are B-size.
Questions, corrections, comments? Let us know in the comments below.
