Start from the wall and work backwards
A datasheet is written to be read in the order the product was designed, which is rarely the order you need it. Read an optical glass color filter sheet backwards: start from the image you want on the wall, then the distance, then the optics, then the light source. The headline wattage is the last thing to look at and the first thing most people compare.
Output numbers, ranked by how much they lie
Wattage tells you the running cost, not the result. Two optical glass color filter 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 an optical glass color filter intended for a hotel entrance, 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 30 m | 1.5 – 3 m | Where lens quality starts to matter |
| Long, beyond 30 m | 3 m and up | Contrast fails before reach does |
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 optical glass color filter 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 optical glass color filter is and how it is resolved. A supplier who answers honestly is worth more than one with a slightly better spec sheet.
