General information, optic specifications, index

L966D967_SRC.QXD 11-03-2004 08:25 Pagina 12.28
Information – Specification data lamps
Damage factor / Fading
Radiation in the form of light or heat can cause damage to objects or
merchandise being displayed.The extent of deterioration of objects
upon exposure to light, such as fading colours and disintegration of
structure and material, depends on:
- the sensitivity of the material and the capacity of the material to
absorb and be affected by radiant energy
- the illumination level
- the time of exposure to radiation
- the spectral composition of the radiation.
Having no classification for the sensitivity of materials related to the
amount of damage under a certain light source, the only indication
which can be given is the ‘probable damage’ caused to an object.
This method ignores the spectral sensitivity of the object concerned,
and only results in the relative damage caused by one light source
compared to another. Each light source can be characterised by the
damage factor DF, which yields the relative damage caused by this
source compared to other sources, provided the illuminance and
exposure times are constant.
The fading risk (FR) is the damage caused by one light source,
calculated for a certain period of time, relative to a reference.
A fading risk FR=160 is obtained in a ‘worst-case’ situation, e.g. an
object in a shop window illuminated by bright sunshine (10,000 lux)
for a period of 1 hour.
Example 1: the formula mentioned in the table for an illuminance of
500 lux, realised with fluorescent lamps /830, results in a fading risk
FR=2.The fading of pigments occurs here 80 times slower than at
the reference FR=160, i.e. it is negligible.
Example 2: an accent projector produces 10,000 lux at a certain
display.Applying e.g. a MASTER Colour CDM lamp results in a fading
risk FR=40.
Light sources with more ultraviolet radiation, such as metal-halide
lamps without UV-filter or open halogen lamps, might, at high lighting
levels, result in damaging radiation.
12.28 GENERAL INFORMATION, OPTIC SPECIFICATIONS, INDEX
Daylight conditions /
light source
Overcast sky – average
Sunlight – average
Daylight through 4 mm
window glass
Incandescent lamp
PAR38
PAR38 cool beam
Open halogen lamp
Closed halogen MASTER line ES
MASTER Colour CDM
White SON SDW-T
Open metal halide lamp
Closed metal halide lamp
Fluorescent lamps - colour
/827
/830
/840
/850
/865
/927
/930
/940
/950
/965
/29
/33
/79
Damage factor
1.52
0.79
0.43 – 0.68
0.08
0.11
0.07
0.17
0.10
0.22
0.10
0.50
0.25
0.19
0.20
0.21
0.22
0.24
0.15
0.15
0.18
0.22
0.24
0.17
0.24
0.22
FR (fading risk) = 0.02 DF x E x T where
DF: damage factor
E: illuminance, expressed in lux.
T: time in hours