Philips Indoor Luminaires Indoor Furnishings User Manual


 
Lighting technique
Philips indoor luminairesTechnical data12.52
Accent factor
The visual effect achieved when an object is highlighted to reveal its
three-dimensional shape is determined by two items, i.e. the luminance
between the object and its surrounding background, called contrast,
and the light and shadow effects in the object itself caused by the
shape and texture and the position of the spotlight, called modeling.
The main lighting characteristics of a light source that determine the
contrast are the diameter or size and the sharpness of the contour of
the visual beam.
When planning accent lighting, it is important to determine the
required effect or accent factor, which may vary from ‘noticeable’ to
‘very dramatic’. What is important here is the relationship between the
amount of general lighting in the direct vicinity of the object and the
brightness of the spot on the object. The accent factor is calculated by
dividing the lighting level in the spot by the general lighting level in the
horizontalplane,approximately1meterabovetheoorinthedirect
vicinity of the object.
Accent factor =
Lighting level in the spot (on illuminated object)
General lighting level (in horizontal plane)
To obtain satisfactory effects in situations where the level of general lighting is high or
there is incident daylight, powerful accent lighting should be used.
Figure Accent factor Effect
1 2:1 Noticeable
2 5:1 Low theatrical
3 15:1 Theatrical
4 30:1 Dramatic
5 50:1 Very dramatic
1.Noticeable visual effect
(factor 2:1)
2.Low theatrical effect (factor 5:1)
3.Theatrical effect (factor 15:1)
4.Dramatic effect (factor 30:1)
Can only be achieved with relatively
low general lighting levels.
5.Very dramatic effect (factor 50:1)
Can only be achieved with relatively
low general lighting levels.
Indoor_2008_Chapter_12_LIS.indb 52 20-05-2008 14:35:43