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Understanding light sources

Date:2010-07-22

To establish the correct light source for a given application, you need to consider two factors. Fortunately, VeriVide has already considered them for you, so to find the right lamp(s) for your particular needs, just ask us. But for the record, the two factors are: 

Colour temperature

This is expressed as Kelvin (K) and has nothing to do with heat. Instead it attaches a value to the colour appearance of a light source, and this varies with its spectral power distribution. For example, fluorescent lamps such as the CIE Illuminant 'A' and the Warm White Fluorescent have lower colour temperatures and so look red; while fluorescent lamps such as the VeriVide D65 and D75 have higher colour temperatures and so look blue.

Colour rendering index (CRI)

CRI values measure how well a lamp renders colours relative to a reference light source. The CRI index ranges from 0-100, with 100 representing an exact match. A lamp such as the VeriVide D65, with a CRI of 98, will therefore show colours more accurately than a lamp such as the CWF, with a CRI of 62. CRI rating is recognised by the Illuminating Engineering Society (IES) and the Commission International de L'Eclairage (CIE).