Color Temperature and Color Rendering Index

To choose the right color fluorescent lamp for a specific application, consider two things: (1) Color Temperature, and (2) Color Rendering Index.

Color Temperature is expressed in degrees Kelvin (K). For example, noon daylight is about 5500 degrees Kelvin – the same as the full spectrum Vita-Lite. Fluorescent lamps with lower color temperatures look red; fluorescents with higher color temperatures look blue. This makes sense if you imagine an iron bar being heated. First it gets "red hot." Then, as the temperature increases, it becomes "white hot" and finally, "blue white" hot.

Color Rendering Index (CRI) is a numerical system that rates the "color rendering" ability of fluroescent light in comparison with natural daylight, which has a CRI of 100. This means that a lamp with a CRI of 91 shows colors more naturally than a lamp with a CRI of 62. Most standard "cool white" fluorescent bulbs range 60 to 75 CRI. This rating method is recognized by the Illuminating Engineering Society (IES) and the Commission International de L'Eclairage (CIE).

 

Color Temperatures of Duro-Test Fluorescents
Lamp Color Description
Color Temperature
C.R.I.
Color Classer 75
7500
93
Color Classer 75 Plus
7500
91
Vital-Care 75
7500
91
Daylite 65
6500
92
Vita-Lite
5500
91
Vita-Lite Plus
5500
91
Vita-Lite Supreme
5500
96
Natur-Escent
5500
89
Aurora V
5000
85
Optima 50
5000
91
Color-Gard 50
5000
91
Color-Matcher 50
5000
90
Classic-42
4200
82
Cool White
4200
62
Aurora IV
4000
85
Classic-35
3500
85
Optima 32
3200
82
Color-Gard 32
3200
82
Aurora III
3000
85
DSW 30
2770
79