In principle, the artificial light and natural light should be the same, the people's right to the naked eye to distinguish the color of things, of course, that according to the location and lighting for the purpose. Light color for the display of objects known as the color of. Usually called "color-rendering index" (Ra).
The color of the things that is the true color (color of its own) and a light source under the standard color display relations. Ra value of the determination is to DIN6169 standard definition of the eight colors in the standard test source and the source under test done, the smaller the color detected light indicates that the color of the color better.
Ra value of 100 light that things in its lighting and the colors are displayed in the standard under the same light source.

 Generally speaking, the direction of light emission are different, and different intensity. Visible light in a particular direction by the angle of emission intensity is called intensity. The unit is: Candela [cd].

Just electromagnetic radiation to the eye, the optic nerve into light, which can be the naked eye to see that part of spectrum. Such rays in the wavelength range 360 nm to between electromagnetic radiation spectrum is only a very small part. The temperature far higher than 50Hz when the temperature, resulting in a higher color temperature and white color table of better color

illumination and the luminous flux is the ratio between the exposure area coefficient.
A lx means an average lm flux distribution in the area lm2 plane brightness. Unit: Luck Division [lx].

Source launch reception was in the eye which is the sum of the energy flux (Φ), the unit is: lumens [lm]

Energy-efficiency is converted into energy efficiency. The unit is: lumens / watt lm / W]

 When issued by the light color and "bold" in a color temperature of the radiation, the "bold" as the temperature on the color temperature of the light source. "Blackbody" The higher the temperature, the blue spectral components are more and more red component is less. For example, incandescent light is warm white color, the color temperature of 2700K said, and color fluorescent daylight color temperature of 6000K that is the method. The unit is the color temperature: Kelvin [K]