There are three requirements for seeing color: an object + an observer + a light source. If any of these is missing, no color will be seen + if any is changed, the color will change. When light strikes a colored gemstone, some wavelengths are absorbed and some are transmitted.
Light Sources
Sunlight = light coming directly from the sun.
Skylight = light that comes from the sky.
Daylight = combination of sunlight + skylight
Artificial Light
In dealing with colored gemstones light plays an important role. Daylight with its shifting intensity and color balance may not be ideal for grading + buying + selling gemstones. Standardized artificial lighting with a steady, known intensity and color balance should bring consistency in grading + universal communication for color values.
Types Of Artificial Light Sources
Incandescent light = incandescent lights should not be used because their color temperatures tend to be too low + they emit greater amounts of yellow, orange and red wavelengths.
Fluorescent light = the cool white fluorescent lights found in most offices should be avoided because their color temperatures tend to be too high + they emit large amounts of blue + violet wavelengths.
Daylight fluorescent light = they are designed to simulate daylight + some of them may meet the required standards.
LED = it’s the newest technology on the market + they are generally of low wattage + you may need many bulbs to illuminate a particular display more effectively + they use very little power + last longer + could simulate daylight.
At present a number of different light sources are marketed for a wide range of industries + some are suitable for viewing colored gemstones. For now, there is no internationally accepted standard grading lamp among gem dealers.
Useful links:
www.gelighting,com
www.intl-lighttech.com
www.darksky.org
www.lightingdesignlab.com
www.elec-toolbox.com
www.tir.com
www.lampsplus.com
No comments:
Post a Comment