Glossary of Terms

Glossary of Terms


Amount of light produced by a surface that reflects or emits more light.

Camera illuminance

Quantity of light that shines in the direction of a fixed camera position. Needs to be a consideration for venues that broadcast games.

Colour Rendering Index (CRI)

Scale of 1-100 for how accurately light can show the true colours of an object.

Colour temperature

Look and feel created by the light bulb. Usually denoted as “warm white” or “cool white” bulbs.


Differences in appearance between two parts of a visual field such as in brightness, or colour, or both.


Excessive brightness in the visual field. It can create issues for both players and spectators.


Amount of light (luminous flux) falling on a unit area of a surface. Measured in LUX.

Illuminance gradient

Rate that the illuminance on a surface fluctuates with position. Measured as % per metre.

Isolux diagram

Plan of the playing area with lines connecting points of equal illuminance. Can be used to show the amount of light spillage.


Element of a lighting fixture that emits light e.g. bulb. They’re classified into three main types: incandescent, fluorescent, and LED. Outdoor flood lighting and sports lighting include High Pressure Sodium, halogen, and LED.

Light Spillage

Amount of unwanted light travelling onto adjoining areas.


Amount of light which passes through, emits from, or reflects off an object e.g. light emitted from a floodlight over a sports field.


The whole light fitting, including: bulb, housing, reflector, lens and control gear.

Luminous efficacy

Measure of how efficiently a light source converts electric power into light. Measured in lumens per Watt (lm/W).


Lux is a measure of illuminance, which is the amount of light that falls on a surface.

Maintenance factor

Predicts the minimum performance of a lighting system, if it is looked after properly.

Principal area

Playing area for a sport. Normally the area encompassed by the outside line of the pitch or court.

Rated life of a bulb

Expected average operating life of a bulb. The longer the rated life, the lower the maintenance needs for the lighting system.

Reflection factor

Amount of light that is reflected back off a surface.

Stroboscopic effect

Flickering effect caused when a flashing light illuminates a rapidly moving object or player;

producing the illusion that the object is changing speeds rather than flowing smoothly.

Uniformity ratio

Measure of the uniformity of light distributed over the pitch, or court, surface.

Vertical illuminance

Quantity of light on a vertical plane; should be calculated during lighting system design to ensure unrestricted camera positions.

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