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Technical
information
Lighting
Light and colour rendering
The colour appearance will depend on the spectral emission of the light source and the ability of a light source to render colours naturally,
without distorting the hues. An even balance of light and colour define the atmosphere of a room and by the warmth or coldness influences a
persons mood.
The colour characteristics of a lamp are governed by two separate criteria: colour appearance and colour rendering.
Colour temperature
The colour appearance of a light source characterised by the colour temperature Kelvin (K), the higher the temperature of the lamp the whiter
its light.
Colour rendering
The effect that Fluorescent and other types of lamp have on the appearance of coloured objects is indicated by the general colour rendering
index (Ra) scale of eight standard test colours.
Measured on a scale of 0 to 100, where 100 is the equivalent of daylight, higher values indicate better colour rendering. Values of 100-90 are
very good, 90-80 good and those below 80 should not be used where colour rendering is a key factor.
LUX (lux)
The amount of light falling on a surface. Offices are typically lit to between 600 and 800 lux at desktop height.
1 Lux = One lumen per square metre, unit of illuminance.
Lamp types
Tungsten halogen
This light source is more efficient and compact and can therefore be directed to specific areas, producing a bright, white light brighter than
incandescent lamps of the same wattage.
They are dimmable with all forms of modern dimmer control.
Linear fluorescent
Up to 5 times more efficient and lasting up to 8 and even 15 times longer than incandescent. However, unlike halogen and tungsten these
lamps require ballasts that control the current. Dimming can be achieved with many forms of electronic ballast. High output T5 diameter
lamps are becoming the standard for commercial installations.
Compact fluorescent lamps
CFL’s have the same characteristics and advantages of linear fluorescents, but are folded into compact shapes. Many wattages are available,
from 5W to 80W. External Ballast high frequency (Non retrofit) – Compact in size the 2 pin and 4 pin CFL’s require a separate ballast. Integral
Ballast high frequency CFLi or low energy lamps – These lamps have internal electronic ballasts and can be used as direct replacements for
GLS, candles and other lamps. They are central to achieving domestic lighting Carbon Emission Reduction Targets. The availability, types
and styles of CFLi’s and of dimmable versions will increase significantly with the progressive withdrawal of Incandescent lamps from the
marketplace.
LED
Light Emitting Diode lamps can last for up to 50,000 hours. All LED light sources require some form of current control; either built into the
lamp, such as in retrofit GU10’s, or an external driver. For actual illumination the minimum wattage of retrofit lamps should be at least 3
Watts. LED lighting is currently in its infancy but is likely to eventually become a dominant light source. The availability of controllable LED’s is
currently poor but will become more prevalent.