Light Reflectance Value, or LRV, is a measurement most commonly used by design professionals like architectural color consultants, architects, Environmental Graphic Designers and interior designers, which expresses the percentage of light that is reflected from a surface.
LRV is frequently included on the backs of paint chips or samples and is also used by lighting designers to calculate the number and type of light fixtures needed to give a certain amount of light for interior spaces.
Designers of buildings need to comply with the Building Regulations applicable to the structure under consideration. Since 2004 guidance has existed on access to and use of buildings. The guidance is particularly concerned with provisions to assist the disabled, including those who are visually impaired. The guidance highlights the need for certain surfaces and features to “contrast visually” with their surroundings. Areas of particular interest are:
This is relevant to a wide range of non-residential buildings, e.g. hospitals, schools, hotels, theatres, etc.
The current guidance in the Regulations and in the relevant Codes of Practice, BS 8300:2009 is that adequate visual contrast is provided if the Light Reflectance Values (LRV) of the contrasting areas differ by at least 30 points.
Manufacturers are advised, for example, by the Guild of Architectural Ironmongery to publish LRV values for their products. Designers are beginning to demand them.
On signage with words or pictograms The Americans with Disabilities Act Accessibility Guidelines (ADAAG) recommends a 70% light reflectance value but this is not a strict requirement. There are a number of color combinations in the 60-70% range that work well, which is why 70% is not a requirement.
Color contrast is determined by the calculations [(B1 - B2) / B1] x 100
B1 = light reflectance value (LRV) of lighter area, B2 = light reflectance value (LRV) of darker area, (ADA Accessibility Guidelines)
ADA Accessibility Guidelines for Buildings and Facilities (ADAAG) Media related to [//commons.wikimedia.org/wiki/Category:Light_Reflectance_Value Light Reflectance Value] at Wikimedia Commons LRV - What is it? How is it used?