Lighting School

As LED is a relatively new technology and concept in lighting, it is very easy to be overwhelmed by the magnitude of terms and everyone’s opinions. We at Brightlux will supply you with the tools and knowledge that you require to negotiate the minefield of confusion. We present to you, Lighting School.

Lumens
Lumens: A lumen is a unit of measurement that is used to express how bright a light source is. One lumen is equivalent to one candle. A light that outputs 50 lumens is as bright as 50 candles. The higher the number of lumens, the brighter the light. Lumens is also abbreviated as “lm”.

CRI
Colour Rendering (CRI): Colour Rendering Index (CRI) is a way of measuring how vibrant a light source makes colours appear. In other words, it’s a measurement of the light colour quality. The index ranges from 0 to 100. A light’s CRI can only be compared to another light if they have the same colour temperature, which is explained below.

Colour_Temp
Colour Temperature: Colour temperature is the colour appearance of the light. The normal colours you will see advertised are Warm White, Neutral White and Cool White. The lower the colour temperature, the warmer the light appears. Colour temperature is measured on the Kelvin (K) scale.

Design_Lifetime
Design Lifetime: Design Lifetime is the average life of a lighting product when operated at nominal lamp voltage. A light’s lifespan will depend on its type. Incandescents are very cheap and will last approximately one year. In contrast, LEDs have a high initial cost but will not need to be changed for 17 years.

Power_Factor
Power Factor/Luminous Efficiency: Power Factor/Luminous efficacy measures how efficient a light source is at converting electricity power to light. It is measured in lumen output per unit power input (watt). Efficiency = lumen / wattage

Beam_Angle
Beam Angle: Beam angle refers to a light source’s measure of spread and is measured in degrees. A light’s beam angle is determined when its lux level drops to half of the intensity of the centre beam (see diagram). Beam angles are commonly 30, 60 and 90 degrees. LEDs require a lens to create the beam angle as LEDs are directional. The lens used creates the beam angles.

Lux

Lux: Lux is a measurement of the light intensity falling on a surface. This measurement determines the brightness of a light in a space. Lux meters are available to determine lighting levels and evaluate the energy efficiency of lighting designs.

• One lumen per square meter = One lux


Dimmability2
Dimmability: Dimmable lights can be adjusted to the right intensity and deliver different amounts of light for different occasions and times. The range of light levels a bulb can produce will be affected by its dimmability. Not all LED lightbulbs are dimmable but this will be clearly stated on the packaging.

Electricity
Design Lifetime: Design Lifetime is the average life of a lighting product when operated at nominal lamp voltage. A light’s lifespan will depend on its type. Incandescents are very cheap and will last approximately one year. In contrast, LEDs have a high initial cost but will not need to be changed for 17 years.