Colour temperature is usually chosen by habit, warm for heritage, cool for modern. A better starting point is the material itself.
Stone
- Limestone and sandstone come alive under warm white (2700 to 3000 K). Cooler light makes them look grey.
- Granite and dark stone reflect little light; they often need more output, and a neutral white can bring out mineral colour.
- Marble and white stone tolerate a wider range; very warm light can turn them yellow.
Glass
Glass transmits and mirrors light instead of holding it on its surface, so lighting it directly rarely works. Light the frame, the mullions or the interior behind the glass instead.
Metal
- Bronze, copper and corten suit warm and very warm white (2200 to 3000 K).
- Aluminium and stainless steel look clean under neutral and cool white (3500 to 4000 K), but watch for specular glare.
Timber and planting
Timber and leaves generally look better under warm white. Cool white on foliage tends to look artificial.
Mixing colour temperatures
Two colour temperatures can separate a building's base from its crown, or a facade from its landscape. More than two usually looks accidental.
Many of our architectural luminaires offer several colour temperatures from 1800 K to 6000 K, test two options side by side on the real surface before deciding.