Precision light measurements require a controlled environment, but we do not live in a controlled environment, with controlled light sources. Get Luminance is subject to the same constraints of other photometric equipment used in changing conditions.

· Prevailing, or ambient light, varies all the time.

· Where there are horizontal and vertical components of a light source, the angle of measurement will affect readings.

· Errors in photometric measurement – small errors in photometric measurement can lead to large errors, especially at a few discrete wavelengths.

· Accuracies of illuminance meters +- 5%, with a deviation from average 7%-12.5%.

· Device models are different with different sensors and pixel sizes. Some device sensors will render colours slightly differently (just like a TV, monitor, or camera).

Get Luminance provides a specular component exclusive measure of luminance as captured by a photograph, using colorimetric information.