OSRAM DULUX F - Manual (Page 36)

Economical long-life light sources with plug-in bases
Compact Fluorescent Lamps OSRAM DULUX ®
Technical Guide
34
2.3 Photometric data
2.3.1 Light colours
The light colours of the lamps are divided into three groups, each covering a particular colour tem-
perature range.
Light colour Colour temperature
Daylight > 5000 K
Cool White 3300 - 5000 K
Warm White < 3300 K
The light colour is determined by the x and y coordinates in the chromaticity table. For practical
purposes, it is important to know the colour rendering properties of the lamps in addition to their
light colour and colour temperature. These properties are defined by the (general) colour rendering
index R
a .
The colour rendering index (computed using the CIE method) provides an indication of how non-
luminous colours will appear when illuminated by the relevant light source.
Colour rendering is assessed by comparison with a Planckian radiator (< 5000 K) and normalised
daylight (> 5000 K) of the same colour temperature. By definition, these radiators have the ideal
colour rendering index of 100. Any deviation from this ideal is rated with values lower than 100.
The general colour rendering index R a is the average value of eight different internationally stan-
dardised test colours (CIE).
There are various ranges for the Ra value, known as colour rendering groups:
Ra value
Group
(according to EN 12464-1)
Characteristic
90 - 100 1A Very good
80 - 89 1B Very good
70 -79 2A Good
60 - 69 2B Good
40 - 59 3 Satisfactory
20 - 39 4 Unsatisfactory
Note:
The colour perception of a non-luminous colour therefore always depends on the colour tempera-
ture of the illuminating lamp and colour rendering properties of this lamp.
Example:
Blue tones will always appear brighter in the light from a lamp with a daylight colour than in the light
from a lamp with a warm white colour, even if both lamps have an R
a value of 100.
OSRAM DULUX ® single-capped fluorescent lamps are available in LUMILUX ® and LUMILUX ® DE
LUXE light colours. The most economical lighting is achieved with LUMILUX ® . These light colours
fall into colour rendering group 1B, which means they are ideal for most applications (including
office and shop lighting, hotel and restaurant lighting, living rooms and outdoors). In places where
colour rendering is a particular important factor (e.g., art galleries, museums, laboratories and
graphical trades), OSRAM DULUX
® lamps are also supplied in LUMILUX ® DE LUXE light colours.
As group 1A lamps, these offer the best colour rendering. However, their luminous flux is lower than
their LUMILUX
® counterparts; therefore more lamps are needed to achieve the same lighting level.
Ultimately, the choice of light colour depends on the specific application, room conditions and per-
sonal preference.