Light Reflectance Value. The light reflectance value is the proportion of light reflected by a colour, as measured in daylight conditions. The greater the light reflectance value, the lighter the colour. White and very bright yellows have the highest light reflectance values. The impact of a colour within the overall colour scheme can be estimated by multiplying the light reflectance value by the proportion of the area in which it is used. The total light reflectance value of a scheme can be estimated by adding together the figures for each colour used. In static conditions, a difference in these values of 30% or more is considered to be adequate, though a best practice application would employ a considerably stronger contrast than this, particularly in relation to key safety features, where the strongest possible contrast should be used.