National Physical Laboratory

Colour Measurements

Image courtesy of iStockphoto
Image courtesy of iStockphoto

The colour of a material or object can be represented by its spectral 'fingerprint' (i.e. its spectral reflectance or transmittance) or in terms of colorimetric values such as (but not limited to) x, y, u', v', L*, a*, b*. These can be calculated for CIE 2° and 10° Standard Observers and CIE Standard Illuminants A, C, D50, D65.

NPL measures the colour of reflective samples using a calibrated spectrophotometer which may be used in 0°:45°a, specular included (8°:di) and specular excluded (8°:de) geometries and has a resolution down to 1 nm over the spectral range 380 nm to 780 nm. The results are traceable to the NPL 2007 spectral reflectance scale and are typically quoted for a temperature of 23 °C. Services for colour of transmissive materials are also available.

Clients will receive a UKAS accredited calibration certificate (available as both electronic and hard copy).

More detailed information



Customer Service tel: +44 20 8943 6151

Last Updated: 22 May 2014
Created: 5 Aug 2009


Please note that the information will not be divulged to third parties, or used without your permission