LIGHTING 01

deliberate use of light to achieve practical or aesthetic effects

LIGHTING (illumination)

main source of light during daytime

DAYLIGHTING

unit of luminous intensity of a light source; brightness of a light source

CANDLE POWER (CP

index of the ability of a light source to produce illumination

CANDELA (cd) (SI units)

quantitative unit for measuring flow of light energy (measuring the total amount of visible light emitted by a source)

LUMEN

density of the luminous flux (lumens per unit area)

ILLUMINATION

1 lumen of luminous flux spread uniformly over an area

FOOTCANDLE (FC)

ratio of light absorbed by a material to the incident light falling on it

ABSORPTANCE

regular reflection (observed in mirrors)

angle of reflection = angle of incident light

SPECULAR REFLECTION

reflected light is scattered in all directions

DIFFUSE REFLECTION

light passes through clear, transparent materials

DIRECT TRANSMISSION

transmitted light is scattered evenly

DIFFUSE TRANSMISSION

bending of a ray light as it passes obliquely through a material

REFRACTION

a quantitative unit for measuring brightness

FOOTLAMBERT (FL)

index of the intensity of light being emitted, transmitted or reflected from a surface

BRIGHTNESS

effect of excessive brightness in the field of view

GLARE

ultimate primary source of light

SUN

generic term for artificial light source

LAMP

complete lighting unit consisting of a lamp (referred to as a fixture)

LUMINAIRE

device for redirecting radiant energy of a lamp by reflecting it in the desired direction

REFLECTOR

device for redirecting radiant energy of a lamp in the desired direction through a lens

REFRACTOR

the ratio of light output to the light produced by the lamp

EFFICIENCY

the ratio of output of luminous flux, expressed in lumens (lumens per watt)

EFFICACY