LED:

Short for light-emitting diode. An electronic semiconductor device that emits light when an electric current passes through it.

R9 VALUE:

R9 is one of 6 saturated test colours not used in calculating CRI Butchers, bakers, surgeons and fashion retailers are among those who need their lights to render red really well.

CRI:

Colour Rendering Index is a quantitative measure of the ability of a light source to reveal the colours of various objects faithfully in comparison with an ideal or natural light source.

LUMEN PER WATT RATIO:

Luminous efficacy is a measure of how well a light source produces visible light. It is the ratio of luminous flux to power.

FLICKER RATE:

Unless a person is in natural daylight, they are likely to be exposed to this higher frequency flickering, because all mains-powered light sources, whether incandescent, halogen, fluorescent or LED, are subject to flickering. The source is the AC component of the power supply and the frequency of the flickering is typically either equal to the mains frequency (usually 50 or 60 Hz) or double the mains frequency.