Devices that measure the light level and light specification are called light meter. Light meter devices are used in lighting, photography and cinema industries.
Devices that only measure the light level is called lux meter. Beside lux measurement, advanced devices can also measure color temperature (CCT), color rendering index (CRI), color coordinates (CIE1931/1976), light spectrum, flicker percentage.
Light meter devices are used to measure the light level of indoor and outdoor places. Values that obtained as a result of measurement compared with minimum requirement of the standard about an application, therefore, it is decided whether lighting is sufficient.
Mobile, hand type devices are commonly used in light measurement. Measurement devices should be calibrated before each test in order to obtain accurate measurement. Calibration maintained by closing the light-proof cover on measuring sensor and pairing it with 0 lux.
Light measurement which has done with the help of more than one sensor, converted to lux value after the process with software.
The measurement of incandescent light sources, the values resulting from the measurement can be correct. However, the situation is different for other light sources.
Some problems can emerge when measuring LED lights and some other technologies with light measurement devices. Because the human eye can only sense a specific range of light waves. In order to obtain a correct measurement, light measurement device should be calibrated according to human perception of light.
For example, a standard light meter can measure 300 lux value in a place that illuminated with LED lighting. However, the human eye may see 200 lux instead of 300 lux value. For this reason, advanced devices that only photopic view that is paired with the sensitivity of the human eye, in other words, measure light that only the human eye can detect, should be used.