|
ARTIFICIAL
LIGHT |
|
The
Conventional Incandescent Lamp (Bulb) |
| This
incandescent lamp generates light by thermo-radiation as the result of
passing electricity across a conductor filament. A large part of the
electrical energy absorbed by the lamp is lost as heat, so that the light
efficiency is highly reduced. The light of a bulb lamp is equal to "Light Source (A)" |
"Color Temperature" 2856 "Kelvin"
CIE-1931 Coordinates
x=0.4476 y=0.4075 |
|
The
Tungsten Halogen Incandescent Lamp |
| An
incandescent lamp with added halogen (Iodine). The iodine combines with
the vaporized wolfram of the filament. This results in fewer deposits of
tungsten particles, which enhances light flux maintenance and an increased
lamp duration. The filament works at a higher temperature than the
conventional lamp and results in a higher emission level, with a
substantial improvement in efficiently. |
"Color
Temperature"
about 2650 -
3400 "Kelvin"
|
|
The
Fluorescent Incandescent Tubes |
|
Light
as a result of ionization. There are fluorescent tubes in basic
tones |
| a
reddish Warm-White |
from
2700 up to 3000 "Kelvin" |
| a
greenish White |
from
4000 up to 5000 "Kelvin" |
| a
bluish White (seems like daylight) |
from
5300 up to 5600 "Kelvin" |
| An imitation of Light Source (A) |
Philips
TL27 (out of production) |
±
2840 "Kelvin" |
| An imitation of Light
Source (C) |
Philips
TL87 (out of production) |
±
6750 "Kelvin" |
|
- |
|
- |
Xenon |
from 5290 up to 6000 "Kelvin" |
|
- |
Metal halide |
from 4300 up to 6750 "Kelvin" |
|
ILLUMINATION |
|
. |
| .Common CIE
Standard Illuminants |
|
|
Correlated color
temperature (CCT) |
"Light Source (A)"
It is the only incandescent illuminant |
Incandescent or tungsten light |
Found in our home |
2856 K
CRI-100
CIE-1931 Coordinates x=0.4476 y=0.4075
CIE-1976 Coordinates u'=0.2560 v'=0.5243 |
"Light Source (F2)"
Also called F, F02,Fcw,CWF, CWF2 |
Cool white fluorescent lamp |
Found in office environments |
4230 K CRI-64
CIE-1931 Coordinates x=0.3721 y=0.3751 |
| "Light
Source (D65)" |
Noon daylight - Special
daylight -Natural daylight |
Found in color measurements
Represents a full, even spectrum |
6504 K
CIE-1931 Coordinates x=0.3127 y=0.3291
CIE-1976
Coordinates u'=0.1978 v'=0.4684 |
| "Light
Source (C)" |
North
sky heaven - Indirect sunlight - Bluish daylight |
- |
6774 K
CIE-1931 Coordinates x=0.3101 y=0.3163
CIE-1976
Coordinates u'=0.2009 v'=0.4610 |
| CIE Daylight
Series of Illuminants |
|
|
Correlated color
temperature (CCT) |
| "Light
Source (D50)" |
Horizon light
Bright
incandescent light |
Represents warm daylight at sunrise and sunset |
5000 K
CIE-1931 Coordinates x=0.3457 y=0.3586 |
| "Light
Source (D55)" |
- |
Represents mid-morning or mid-afternoon daylight |
5500 K |
| "Light
Source (D65)" |
Daylight |
Represents noon daylight |
6504 K
CIE-1931 Coordinates x=0.3127 y=0.3291
CIE-1976
Coordinates u'=0.1978 v'=0.4684 |
| "Light
Source (C)" |
Historical representation,
which is still in active use
|
Represents north sky daylight |
6774 K
CIE-1931 Coordinates x=0.3101 y=0.3163
CIE-1976
Coordinates u'=0.2009 v'=0.4610 |
| "Light
Source (D75)" |
Overcast daylight |
- |
7500 K |
| CIE
Fluorescent Illuminants |
|
|
Correlated color
temperature (CCT) |
| "Light
Source (F2)" |
Cool white fluorescent |
Found in office environments |
4100 K CRI-60 |
| "Light
Source (F7)" |
Approximates CIE D65 |
Represents a broadband fluorescent lamp |
6500 K CRI-90
CIE-1931 Coordinates x=0.3129 y=0.3292 |
| "Light
Source (F11)" |
- |
Represents a tri-band
fluorescent lamp |
4000 K CRI-83
CIE-1931 Coordinates x=0.3805 y=0.3769 |
|
- |
- |
- |
- |
|
- |
- |
- |
- |
|
- |
- |
- |
- |
| "Light
Source (B)" |
Direct
Sunlight |
- |
4874 K
CIE-1931 Coordinates x=0.3485 y=0.3517
CIE-1976 Coordinates
u'=0.2137 v'=0.4852 |
|
"Light Source (E)" |
Normalized Reference Light |
- |
5500 K
CIE-1931 Coordinates x=0.3333 y=0.3333
CIE-1976 Coordinates
u'=0.2105 v'=0.4737 |
|
|
|
|
|
- |
Noon sunlight
plus light
from a clear blue sky |
- |
6100 - 6500 K |
|
- |
Overcast sky, midday |
- |
6700 - 7000 K |
| Clear blue sky, midday |
- |
12000 - 26000 K |
|
EXPLANATION |
| "Color
Temperature" |
As
the temperature at which a black body emit radiation of the same color as
a given object. The law that energy associated with electromagnetic
radiation, as light, is composed of discrete quanta of energy, each
quantum equal to Planck's constant times the corresponding frequency of
the radiation: The fundamental law of quantum mechanics. Also called
PLANCK RADIATION FORMULA or THE PLANCK'S LAW. (named after "Max
Planck")
The color temperature of a light source is a measure of the integrated
spectral energy distribution of that source. The standard for measuring
color temperature is based upon the temperature of a theoretical black body
(Planckian) radiator.
As the color is increased, the emission of the radiator changes from dull
red to bluish white. The temperature reading is expressed in Kelvin (K)
scale (the same numeric values as the Absolute scale), which equals the Celsius
reading plus 273º. In practice, most light sources do not
duplicate the energy distribution of a black body radiator, so the term correlated
color temperature is used to mean the color temperature that
most closely resembles the light source in question. |
| "Color Rendering Index" |
The Color Rendering Index (CRI) (sometimes called Color Rendition
Index), is a measure of the ability of a light source to reproduce the
colors of various objects being lit by the source. It is a method
devised by the
International Commission on Illumination (CIE). The best possible
rendition of colors is specified by a CRI of one hundred, while the very
poorest rendition is specified by a CRI of zero |
| "Max
Planck" |
|
Planck Max, Karl,
Ernst
(A German physicist Nobel prize 1918)
b-1858-04-23
Kiel, Germany
d-1947-10-03
Göttingen, Germany |
|
"Light
Source (A)"
|
A tungsten
filament lamp operated at a color temperature of 2856 Kelvin, approximately
a blackbody operating at that temperature. A
standard illuminant for color measurement (less blue more red) |
The energy ditribution of
"Light
Source (A)" |
 |
| "Light
Source (B)" |
An
approximation of noon sunlight having a correlated color temperature of
approximately 5000 Kelvin and obtained by a combination Light Source (A)
and a special filter. |
| "Light
Source (C)" |
An
approximation of overcast daylight having a color temperature of
approximately 6774 Kelvin and obtained by a combination of Light Source
(A) and a special filter. The old standard illuminant for color
measurement. |
The energy
ditribution of
"Light
Source (C)" |
 |
| "Light
Source (D65)" |
In
1965 the "CIE" recommended new illuminants to
supplement the Light Sources (A), (B) and (C) designed by (D) and a number
corresponding to its color temperature. The most important of this series
is D6500 with a correlated color temperature of 6500 Kelvin. A standard
illuminant for color measurement (less red more blue) |
The energy ditribution of
"Light
Source (D65)" |
 |
| "Kelvin" |
As
the absolute scale of temperature in which the degree intervals are equal
to those of the Celsius scale and in which 0 Kelvin equals
minus 273.16°
Celsius.
The Absolute Zero, the lowest temperature theoretically
possible. (named after "W.T. Kelvin").
Previously called degree Kelvin. |
| "W.T.
Kelvin" |
|
Kelvin William
Thomas 1st Baron
(An English physicist and mathematician)
b-1824-06-26
Belfast, Country Antrim, Ireland
d-1907-12-17
Netherhall, Ayrsshire, Scotland |
| "CIE" |
Commission
Internationale de l'Éclairage.
In English: The International Commission on Illuminant.
The main international organization concerned with problems of color and
color measurement. |
