Start from the wall and work backwards
Most storefront 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 storefront 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
Check whether the quoted throw is to a white wall in a dark room, because that is where the number comes from. On a storefront gobo projector intended for an entrance threshold, 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 3 m | 0.5 – 1.5 m | Bright and easy — most indoor work |
| Mid, around 15 m | 1.5 – 3 m | Where lens quality starts to matter |
| Long, beyond 15 m | 3 m and up | Contrast fails before reach does |
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 storefront 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
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 a storefront 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
Four questions separate a supplier who knows the product from one reading a sheet. What is the image width at my throw distance? What is the gobo image area? Is the IP65 rating for the housing alone or the whole assembly? And what is the lead time on a replacement gobo? A good supplier answers all four in one reply.
