Start from the wall and work backwards
Nothing on a spec sheet is dishonest; plenty of it is irrelevant. an advertising gobo projector sheet will quote lumen output, power draw and beam angle, but what you need is image width at your throw distance and contrast against the light already on the surface. Those require two more numbers the sheet usually does not give you, which is why they are worth asking for.
Lumens, watts and what reaches the wall
Treat the lumen figure as a rough sorting tool and nothing more. It ignores the lens, the gobo transmission and the colour filter, any of which can take a third of the output. For an advertising gobo projector in the 50–300 W class, ask instead for measured image lux at a stated distance — a supplier who has that number has actually tested the unit.
| 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 |
Throw distance and image size
Throw distance without image width is meaningless, and plenty of sheets quote only one. an advertising gobo projector that throws 40 m might give you a 1 m logo at that distance or a 6 m one, depending on the lens — a difference that decides whether the install works. Always ask for the pair: distance and the resulting image size.
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 advertising 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.
IP rating and electrical data
IP67 is the number to check for anything outdoors, but read what it covers. The first digit is solid ingress, the second is liquid. IP67 on an advertising gobo projector means dust-tight and protected against water jets, and it says nothing about the bracket, the gland or the connector, which are the parts that actually fail. Ask whether the rating covers the whole assembly or just the housing.
What a good supplier answers without hesitating
The most revealing question is about failure. Ask what the most common warranty claim on this advertising gobo projector is and how it is resolved. A supplier who answers honestly is worth more than one with a slightly better spec sheet.
