Valaistusmäärän

Valaistusmäärän, often translated as illuminance, is a photometric measure of the amount of light that falls on a surface. It quantifies how much luminous flux is incident per unit area. The standard SI unit for illuminance is the lux (lx), which is defined as one lumen per square meter (lm/m²). Alternatively, the foot-candle (fc) is sometimes used, where one foot-candle is equal to approximately 10.764 lux.

Illuminance is a critical factor in many aspects of human activity and the natural world. In interior design and architecture, appropriate illuminance levels are essential for tasks like reading, working, and general comfort. For example, a desk for detailed work might require significantly higher illuminance than a living room area. In outdoor environments, illuminance affects plant growth and animal behavior.

The measurement of illuminance is typically performed using a light meter, also known as a lux meter. This device has a photosensitive surface that converts incident light into an electrical signal, which is then displayed as a reading in lux or foot-candles. Factors influencing illuminance include the intensity of the light source, the distance from the source to the surface, and the presence of any obstructions or reflective surfaces. Understanding and controlling illuminance is crucial for visual performance, safety, and aesthetic considerations.