Read the sheet in the order it is installed
Nothing on a spec sheet is dishonest; plenty of it is irrelevant. A long throw 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.
Output numbers, ranked by how much they lie
Wattage tells you the running cost, not the result. Two long throw gobo projector models at the same wattage can differ by 30% at the wall because of lens efficiency and LED binning. What you actually care about is contrast: the image needs to be meaningfully brighter than the surface it lands on, and that is a lux comparison, not a lumen one.
| 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
Throw distance without image width is meaningless, and plenty of sheets quote only one. A long throw gobo projector that throws 80 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.
| Throw | Typical image width | Practical note |
|---|---|---|
| Short, around 20 m | 0.5 – 1.5 m | Bright and easy — most indoor work |
| Mid, around 80 m | 1.5 – 3 m | Where lens quality starts to matter |
| Long, beyond 80 m | 3 m and up | Contrast fails before reach does |
The optical spec most sheets leave out
Gobo size is quoted as an outer diameter, but what matters is the image area — the part the light actually passes through. A 53 mm gobo may only have a 45 mm image circle, and artwork sized to the outer diameter gets cropped. For a long throw gobo projector, ask for both figures before you commission artwork, because a file drawn for the wrong one is wasted.
IP rating and electrical data
The electrical block is boring and expensive to get wrong. Confirm the input voltage range matches your supply, check whether the long throw 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.
What a good supplier answers without hesitating
The most revealing question is about failure. Ask what the most common warranty claim on this long throw gobo projector is and how it is resolved. A supplier who answers honestly is worth more than one with a slightly better spec sheet.
