According to "Practical Lighting Solutions for Your Shop"; PICTURE FRAMING MAGAZINE, November, 2002...
For most retailers it's best to duplicate the lighting where our work will hang. That is, in private residences, where incandescent lighting dominates. We could spend a fortune to duplicate natural light, or control it the way museums do, but it would probably be money wasted. The home environment is not perfectly lighted, and we don't need the carefully-controlled illumination areas demanded by museums.
Lighting may be selected by balancing these two color considerations:
Color Rendition -- This refers to the way a particular color looks when illuminated by a particular light source. It is rated on a scale called the Color Rendering Index (CRI). This gives us the most realistic representation of how light from a particular source will look in use. The higher the CRI, the more accurately colors will be represented.
Color Temperature -- This refers to the appearance of the light source, such as "cool" or "warm". It's measured in degrees Kelvin. "Neutral" light temperature is in the range of 3,000 K to 4,100 K.
Standard incandecent lighting has a CRI of about 95, and color temperature of about 2,700 degrees K. Sunlight at noon is generally considered to be the perfect CRI of 100, and measures about 4,600 degrees K.
There's a lot more information in the article, about other considerations such as control, installed cost-effectiveness, efficiency, and other important stuff.
In my store we use a mix of incandescent (halogen) 130 volt, 90 watt flood & spot lamps, with color-corrected #F32T8/TL735/ALTO fluorescents, which have a color temperature of 3,500 K and CRI of 78. These are energy-efficient lamps & require current-technology fixtures. That is, if you are retro-fitting old fixtures, you might not be able to use these.
There's more to good lighting than meets the eye.
Sorry to be so long-winded with this...
[ 01-31-2004, 03:45 PM: Message edited by: Jim Miller ]