Light Colour
The colour of light is represented by the temperature in degrees Kelvin
(Kelvin is a basic unit of thermodynamic temperature). "White" light is at
5600K.
1800 K - Candlelight
2700 K - Tungsten bulb (house bulbs, parking lights, sealed beams)
3200 K - Halogen bulb (uses tungsten filament)
4300 K - OEM HID light
5500 K - Camera flash
5600 K - White light reference point (midsummer sunlight, Washington DC)
5800 K - Directly overhead sunlight at the equator (the surface temp of the sun)
7000 - 12000K - light under overcast skies (reduced contrast)
12000 K and up - Ultra Violet light
Lighting for photography and movie work is typically either at 5000K,
5500K or 5600K. By choosing HIDs at either 5000K or 6000K you will get
the whitest light. Light at a source below 5000K takes on an
increasingly yellow tinge, while light above 6000K becomes increasingly
blue and purple. Contrast is strongest to the human eye when light has
a slight yellow tinge (thus high contrast glasses and ski goggles are
yellow-orange) and light beyond 6000 K sees contrast fall dramatically.
5000K light offers slightly higher contrast for the human eye than 6000K
light. On the other hand 6000K light has a very attractive purity to
it as it is the closest HID colour to overhead sunlight.
lifted from
www.hid50.com