YOUR WORLD, OUR LIGHT

TECHNICAL TERMS
COLOUR RENDERING INDEX
BASIC CONCEPTS
Basic terms Unit Symbol Definition
Luminous flux Lumen [lm] Ф The total quantity of light emitted from the light source
Colour Rendering Index (Ra) is a measure of colour rendering fidelity, where the point of
reference is the Day light (Ra = 100). The index is closely dependent to the spectral distribution
of radiation. In the light spectrum, very often happens that some wavelengths are
not emitted. In practice that means problems with differentiating these colours .
outdoor use
very good
COLOUR RENDERING
indoor use
very good
good
good
mediocre
Luminous intensity Kandela [cd] I= Ф/ω The luminous intensity I evaluates the light radiated in a definite direction.
It depends on the luminous flux Ф in this direction and on the radiated solid
angle.
mediocre
recognizable colors
insufficient
Natężenie
oświetlenia
Illuminance
Lux [lx] E= Ф/S The illuminance E is the luminous flux Ф on a defined surface A.
DILATATION ANGLE OF BEAM
Dilatation angle of β beam is an angle on the plane running through the axis of the beam,
in which the luminous intensity l equals 50% of maximal luminous intensity.
Luminancja
Luminance
Kandela na
m2 [cd/m2]
Kandela pro m2
[cd/m2]
L=I/S’
The luminance is the luminous intensity per m2 of visible surface. The
luminance L of an illuminated surface is the measure for the luminosity
perceived.
LIGHT SPOT CHART
COLOUR TEMPERATURE
color impression
The light spot chart allows deciphering information about the light beam mainly from
rotating-symmetrical frames. On the basis of the chart we can decipher the maximal
luminance, average luminance on the area restricted by dilatation angle of light spot.
The colour temperature of light is determined by comparing the colour of light
emitted by a source with corresponding colour of light emitted by „black body”
heated to a certain temperature, measured in Kelvins. The distribution of colour
temperature is presented graphically on the Planck curve.
similar to bulb light
similar to halogen to bulb light
day light
„cosy” very warm
„fresh” warm
white – stimulating
cold white
RESTRICTION OF GLARE
Restriction of direct illumination from the luminaire must be done in range of angles from
45° to 85°. Restriction of illumination increases the quality of light and working comfort.
In order to evaluate the quality of light we use Sollner’s curves on basis of which we can
decipher whether the frame fits in the range determined by class.
RESTRICTION OF ILLUMINATION
LIGHT BEAM CURVE
Luminous intensity curve is a graph in polar coordinate system or Cartesian coordinate system,
presenting the light distribution on two planes: C0 i C90. On the graph, the luminous intensity is
presented in candela per 1000 lumens [cd/1000lm]. The digital form of luminous intensity curve
is in most cases a file in eulumdat format used for lighting design in CAD systems.
A 2000 1000 500