Read the sheet in the order it is installed
Most LED 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
Wattage tells you the running cost, not the result. Two LED 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.
Throw distance and image size
Throw distance without image width is meaningless, and plenty of sheets quote only one. an LED gobo projector that throws 35 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.
Gobo size, image area and resolution
Two numbers govern the image: gobo image area and the resolution the lens can carry. Glass gobos can be engraved far finer than any LED 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
IP65 is the number to check for anything outdoors, but read what it covers. The first digit is solid ingress, the second is liquid. IP65 on an LED 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.
Questions worth asking the supplier
Ask for measured figures rather than calculated ones: image lux at a stated distance, image width at your throw, and the gobo image area. Then ask what happens when the unit needs servicing — whether the LED gobo projector can be opened on site without voiding the rating, and how quickly artwork can be re-cut if a branch changes its logo.