Light Reflectance Value, or LRV, is a measurement most commonly used by design professionals like architectural color consultants, architects, Environmental Graphic Designers

Environmental graphic design

Environmental graphic design is a design profession embracing many design disciplines including graphic design, architecture, industrial design and landscape architecture...

 and interior designers, which expresses the percentage of light that is reflected from a surface.

LRV is frequently included on the backs of paint

Paint

Paint is any liquid, liquefiable, or mastic composition which after application to a substrate in a thin layer is converted to an opaque solid film. One may also consider the digital mimicry thereof...

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.

Guidance

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:

• wall to ceiling and wall to floor junctions;
• exposed edges of sloping floors;
• seating and its surroundings;
• leading edges of doors, door opening furniture and door surfaces;
• sanitary fittings and grab bars.

This is relevant to a wide range of non-residential buildings, e.g. hospitals, schools, hotels, theatres, etc.

Codes of practice

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)