Tektronix LumaColor II J18, Instruction Manual

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J18 Photometer Instruction Manual Glossary–1
Glossary
Area Source
A light source of large angular size.
Blackbody (Planckian Radiator)
A thermal light source having light produced by heating. The
intensity and color of a blackbody are primarily dependent on
operating temperature.
Chromaticity
The quality of color. Based on wavelength distribution and
purity.
Color Temperature
The absolute temperature, in Kelvin, of a blackbody required to
produce an equivalent chromaticity from a light source.
Correlated Color Temperature
The absolute temperature of a blackbody required to most
closely match the chromaticity of a light source.
Illuminance
The amount of luminous flux received by a unit of surface area.
Usually measured in lux (lumens/meter
2
) or foot candles with a
sensor spectrally matched to the average human eye.
Inverse Square Law
The falloff of light with distance; light varies inversely with the
square of the distance from the source.
Irradiance
The amount of radiant flux received by a unit of surface area.
Usually measured in watts/meter
2
or watts/cm
2
with a sensor
having equal spectral sensitivity to the wavelengths being
measured.
Isotropic Source
A light source that emits light uniformly in all directions.
J18 Photometer Instruction Manual Glossary–1
Glossary
Area Source
A light source of large angular size.
Blackbody (Planckian Radiator)
A thermal light source having light produced by heating. The
intensity and color of a blackbody are primarily dependent on
operating temperature.
Chromaticity
The quality of color. Based on wavelength distribution and
purity.
Color Temperature
The absolute temperature, in Kelvin, of a blackbody required to
produce an equivalent chromaticity from a light source.
Correlated Color Temperature
The absolute temperature of a blackbody required to most
closely match the chromaticity of a light source.
Illuminance
The amount of luminous flux received by a unit of surface area.
Usually measured in lux (lumens/meter
2
) or foot candles with a
sensor spectrally matched to the average human eye.
Inverse Square Law
The falloff of light with distance; light varies inversely with the
square of the distance from the source.
Irradiance
The amount of radiant flux received by a unit of surface area.
Usually measured in watts/meter
2
or watts/cm
2
with a sensor
having equal spectral sensitivity to the wavelengths being
measured.
Isotropic Source
A light source that emits light uniformly in all directions.