What is illuminance?
Illuminance (symbol: E) is measured in lux (lx) and indicates the amount of luminous flux from a light source falling on a given surface. Illuminance is 1 lux when an area of 1 square metre is uniformly illuminated by 1 lumen luminous flux. Illuminance is measured on horizontal and vertical surfaces, using an illumination photometer. Where a white room and a dark room are provided with the same lighting, the white room appears brighter. What is a glare? Glare can be caused directly by luminaires or other surfaces with excessively high luminance, e.g. windows (direct glare). Direct glare is assessed by the UGR method. It can also be caused in directly by light reflecting from shiny surfaces (reflected glare). Glare impairs visual performance (physiological glare) and visual comfort (psychological glare). What is uniform illumination? For the performance of a visual task, it is important to ensure not only the right lighting level but also the right degree of uniformity in the way the br
