ljósmæling

Ljósmæling is the Icelandic word for photometry, the scientific study of the measurement of light. It encompasses the measurement of luminous intensity, luminous flux, illuminance, and luminous exitance, all of which are measures of light power in the visible spectrum, weighted by the human eye's response to it. Photometry is crucial in various fields, including lighting design, photography, astronomy, and vision science.

In lighting design, ljósmæling is used to ensure that spaces are adequately illuminated for their intended purpose, whether it's for reading, working, or safety. This involves measuring illuminance, which is the amount of light falling on a surface. Astronomers use photometry to measure the brightness of celestial objects, which can reveal information about their size, temperature, and composition. Photography also relies on understanding light intensity to achieve proper exposure.

The human eye's sensitivity to different wavelengths of light is a key factor in ljósmæling. The standard luminosity function, developed based on human perception, is used to weight the measured radiant flux at different wavelengths to arrive at photometric quantities. This ensures that measurements are relevant to how humans perceive brightness. Specialized instruments called photometers or light meters are used to perform these measurements.