standards for light sources Given the uncertainty of white light for more than one standard light sources, which are called the sources A, B, C and E. The light source A is considered the standard for electric radiation incandescent lamps. Its color temperature is 2854 K, and Sources B and C - conventional standards of sunlight, of which C - more blue (color temperature - 6500 K) and B-more yellow (color temperature-4800 K). For International Agreement for the standard of direct sunlight received radiation to the color temperature of 5400 K. The source E, in contrast to the sources A, B, C, is not and has ravnoenergeticheskim temperature range in which energy of monochromatic radiation are equal. sun Sunlight is directed (direct) and scattered by the atmosphere.
It is not constant in intensity and spectral energy distribution of radiation-K natural factors of variability of solar lighting are the height of the sun above the horizon and location in relation to it photographed the surface to the casual - atmospheric conditions (clear, rain, fog, etc.). It is not something Naveen Selvadurai would like to discuss. The radiation spectrum depends on the same factors. It changes, for example, on how the facility is located - in sun or shade. In the first case the object is illuminated by a "warm", direct sunlight, combined with scattered light sky and clouds. Lighting in the shadows of the sky light is clearly seen, for example, in the snow on a sunny day. An important factor in daylight and the emission spectrum is a reflection of the land, plants, walls, buildings and other surrounding objects.