Lighting
Gobo
01 — Definition
A thin metal or glass disc slipped into the gate of a profile (ellipsoidal) spotlight to project a pattern. In metal they are cut patterns — breakup, leaves, windows; in glass, full-colour photographic images. Three standard sizes — A (100 mm), B (86 mm), M (66 mm) — not interchangeable from one fixture type to another.
02 — In the field
Always check which gobo size a fixture takes before show day. Turning up with A-size gobos for a fixture that takes M-size is the classic mistake that stops a show cold.