What is Light Reflectance Value (LRV) ?

Light Reflectance Value (LRV) is the total quantity of visible light reflected by a surface, e.g. floorings, ceilings, walls and furniture, at all wavelengths and directions when illuminated by a light source.

The LRV scale runs from 0, which is a perfectly absorbing surface that could be assumed to be totally black, up to 100, which is a perfectly reflective surface that could be considered the perfect white. Because of practical influences in any application, black is always greater than 0 and white never equals 100. Additional to colour, the structure and gloss of the product or surface are determining factors for LRV.

Some of the current regulations and codes of practice like BS 8300:2009 and BS8493:2008+A1:2010 established the CIE Y value as the single consistent method. It defined that the visual contrast would be sufficient if the LRV of contrasting surfaces, with illumination greater than 200 lux, differs by a minimum of 20 points. This contrast is calculated using the following formula: (B1 – B2) x 100 / B1, where B1 and B2 are the LRV of the lighter area and darker area, respectively.

The LRV can be obtained using the CIE Y values measured under the illuminant D65 (natural daylight) and 10° observer. This measurement can be conducted easily using a sphere-based spectrophotometer.