Read the sheet in the order it is installed
Most gobo projector sheets list ten numbers and leave out the three that decide the result. Work from the wall backwards — image size, throw distance, ambient light — and treat everything else as supporting detail. The numbers that matter are the ones you can verify on site with a tape measure and a lux meter.
Lumens, watts and what reaches the wall
Three output figures get mixed up constantly: lumens describe what the lamp produces, lux describes what arrives on the surface, and watts describe what you pay for. A gobo projector drawing 30–300 W might deliver 3,000 lumens, but the lux at the wall depends entirely on how wide you spread it. The same lamp projecting a 1 m image is nine times brighter than the same lamp projecting a 3 m image.
| Figure | What it measures | How much to trust it |
|---|---|---|
| Lumens | Total light leaving the lamp | Rough sorting tool — ignores lens and gobo losses |
| Lux at the wall | Light arriving on the surface | The number that matters, rarely quoted |
| Watts | Power drawn from the supply | Tells you running cost, not brightness |
The two numbers that must be quoted together
Check whether the quoted throw is to a white wall in a dark room, because that is where the number comes from. On a gobo projector intended for a hotel lobby, the realistic working distance is usually shorter than the maximum on the sheet, since contrast — not reach — is what fails first.
| Throw | Typical image width | Practical note |
|---|---|---|
| Short, around 5 m | 0.5 – 1.5 m | Bright and easy — most indoor work |
| Mid, around 40 m | 1.5 – 3 m | Where lens quality starts to matter |
| Long, beyond 40 m | 3 m and up | Contrast fails before reach does |
The optical spec most sheets leave out
Two numbers govern the image: gobo image area and the resolution the lens can carry. Glass gobos can be engraved far finer than any gobo projector lens in this class will resolve, so the practical limit is optical. That is worth knowing before you pay for engraving detail nobody will see from 10 m away.
The compliance block
The electrical block is boring and expensive to get wrong. Confirm the input voltage range matches your supply, check whether the gobo projector ships with a local plug, and look for CE, RoHS and FCC marks if the install is commercial. A unit that is electrically fine but uncertified will not pass a site inspection in most markets.
Questions worth asking the supplier
The most revealing question is about failure. Ask what the most common warranty claim on this gobo projector is and how it is resolved. A supplier who answers honestly is worth more than one with a slightly better spec sheet.
