Page 188 - The Power of Light, Colour and Sound for Health and Wellness draft

and known as glare – the contrasts are too great for the adaptive range of the eye. High gloss object should thus never be placed in areas of intense illumination. Older window sashes were cleverly moulded to avoid the contrast of sharp incident light entering the interior darkness. Series of curvilinear profles softened the optical succession over glass–sash–frame– wall. Clear lightbulbs can on purpose create a glittering high contrast show known as sparkle. The resulting ambience is one of festivity but the effect should be used with caution. Frosted bulbs will diffuse the light without any disturbing glare or glitter and the outcome is even more pronounced when the light is refected towards the ceiling. An opal light ceiling will give soft uniformity but also erase almost all geometrical information. A foating luminous cloud will seem to hover and the room strangely enough seems darkened.
Colours of light
Often there are many structural colours coexisting or even competing in a room. Multiple surface refections will scatter and intermix the luminous fow in a sometimes, chaotic display. But the general chromatic impression of a space will mostly depend on the principal colour range of the light source. As an active energy supply, it will dominate over the passively refecting pigments. Below are some examples of luminous colour temperatures among common light sources. The letter K stands for absolute temperature in degrees Kelvin starting from minus 273 degrees Celsius.
• Candle
• Incandescent bulb
• Moonlight
• Sunlight
• Light tubes low
• Light tubes high
• Television
1.850 K
2.800 K
4.100 K
6.000 K 3.000-6.000 K 25.000 K 9.3000 K
The visual estimate of the intrinsic colour of an object largely depends on the spectral qualities of the luminous source. Reasonably correct judgments are best made in indirect daylight and meticulous artist will have studios with large windows facing away from the sun. Human perception partly depends on optical variables but also largely on psychological factors. An exact connotation of the colour rendering of specifc lights is therefore somewhat futile. A coarse indication is the rendering average called Ra or the colour rendering index called CRI. A light source is quality ranked by a numerical from 100 to 0. Neutral daylight and fne incandescent bulbs will
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