vertailuvalonlähteellä

Vertailuvalonlähde, meaning "comparison light source" in Finnish, is a crucial concept in photometry and color science. It refers to a standardized and well-characterized light source used as a reference point for evaluating other light sources. The primary purpose of a comparison light source is to provide a consistent and reproducible baseline against which the spectral power distribution, color temperature, illuminance, and other photometric properties of unknown or novel light sources can be measured and compared.

Commonly used comparison light sources include blackbody radiators, which emit a continuous spectrum of light whose color and intensity depend solely on their temperature. Incandescent lamps, operating at controlled filament temperatures, often serve as practical approximations of blackbody radiators. However, for more precise scientific applications, specialized laboratory standards like calibrated tungsten strip lamps or even synchrotron radiation sources might be employed.

The importance of a comparison light source lies in its ability to ensure the accuracy and comparability of light measurements across different laboratories and over time. Without such a reference, it would be difficult to objectively assess the performance of different lighting technologies, such as LEDs, fluorescent lamps, or even natural daylight. This standardization is essential for fields ranging from lighting design and manufacturing to scientific research in optics and visual perception. The selection of an appropriate comparison light source depends on the specific application and the required level of accuracy.