According to BRE’s The essential guide to retail lighting:
Colour appearance refers to the ‘…visual sensation correlated with the ‘warmth’ or ‘coolness’ of the light emitted by a lamp. The metric used to characterise the colour appearance of the light emitted by a light source is the correlated colour temperature (CCT), expressed in Kelvin (K). Warm white light is produced by lamps having a colour temperature below 3,000 K (reddish hues), whereas 4,000 K and above (bluish) is cool and cold white light. The colour appearance is quite separate from the colour rendering of the lamp.’
Colour rendering is ‘The ability of a light source to show surface colours as they should be, usually in comparison with a tungsten or daylight source. Measured on the colour rendering index (CRI) scale. A value of 0 means it is impossible to discern colours at all, and a score of 100 means no colour distortion. For most indoor lighting applications a value of at least 80 is recommended.’
 Related articles on Designing Buildings Wiki
- Ballast or control gear.
- Daylight benefits in healthcare buildings.
- Daylight factor.
- Daylight lighting systems.
- Dichroic reflector.
- Discharge lamp.
- Extra-low voltage lamps.
- General lighting v task lighting.
- Lamp efficacy.
- Light pollution.
- Lighting energy numeric indicator LENI.
- Lighting of construction sites.
- Luminaire efficacy.
- Rights to light.
Featured articles and news
What is liquidation and how does it apply to contractors in the construction industry?
Scrutiny is placed on Carillion's controversial 2013 decision to extend subcontractor payment terms to 120 days.
RSHP unveil their involvement in a boundary crossing which will provide a new entry point into Hong Kong.
With PFI currently under the spotlight due to Carillion, this introductory article explains what they are.
Estimates suggest that up to 30,000 small firms could be at risk of non-payment as a result of Carillion's collapse.
Sir Oliver Letwin to lead an independent review into the delays in the delivery of housing.
As Carillion collapses, read our article explaining insolvency in the construction industry.
43,000 jobs at risk as Carillion declares insolvency..
1961 saw the publication of three important books about urban design that remain relevant today.
Next week the planning fee increases by 20% and new fees are introduced.
How the transformative power of BIM and other digital technologies can be used to gain a competitive edge.