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In architecture, light reflectance value (LRV), is a measure of visible and usable light that is reflected from a surface when illuminated by a light source. [1] The measurement is most commonly used by design professionals, such as architectural color consultants, architects, environmental graphic designers and interior designers.
LRVs are frequently reported on paint chips or paint samples. The values are used by lighting designers to determine the number and type of light fixtures needed to provide proper lighting for interior spaces.
Designers of buildings must comply with the building codes applicable to the structure under consideration. Since 2004 guidance has existed on access to and use of buildings. [2] 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, such as hospitals, schools, hotels, and theatres.
Color contrast may be determined by the formula [(B1 − B2) / B1] × 100, where B1 is the LRV of the lighter area, and B2 is the LRV of a darker area [3]
The British Standards Institute's guidance in the Regulations and in the relevant Codes of Practice, BS 8300:2018, is that adequate visual contrast is provided if the light reflectance values of the contrasting areas differ by at least thirty points. The current British Standard for the measurement of LRV is BS8493:2008+A1:2010.
The Americans with Disabilities Act Standards for Accessible Design does not recommend a light reflectance value for contrast on signage with words or pictograms, but instead it provides that "characters shall contrast with their background with either light characters on a dark background or dark characters on a light background" in § 703.5.1 [4]
The International Code Council utilizes the ADA approach and does not use a light reflectance value in the 2017 update to the standards for ICC A117.1 in § 703.5.3.2 [5]
The United Nations Economic Commission for Europe uses a difference of sixty points between the LRVs for the contrast requirement of signage in "Railway Applications — Design for PRM Use - General Requirements — Part 1: Contrast." [6]
Manufacturers are advised by the Guild of Architectural Ironmongery to publish the LRV for their products. [1]
Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through, is emitted from, or is reflected from a particular area, and falls within a given solid angle.
Daylighting is the practice of placing windows, skylights, other openings, and reflective surfaces so that sunlight can provide effective internal lighting. Particular attention is given to daylighting while designing a building when the aim is to maximize visual comfort or to reduce energy use. Energy savings can be achieved from the reduced use of artificial (electric) lighting or from passive solar heating. Artificial lighting energy use can be reduced by simply installing fewer electric lights where daylight is present or by automatically dimming/switching off electric lights in response to the presence of daylight – a process known as daylight harvesting.
Machine vision (MV) is the technology and methods used to provide imaging-based automatic inspection and analysis for such applications as automatic inspection, process control, and robot guidance, usually in industry. Machine vision refers to many technologies, software and hardware products, integrated systems, actions, methods and expertise. Machine vision as a systems engineering discipline can be considered distinct from computer vision, a form of computer science. It attempts to integrate existing technologies in new ways and apply them to solve real world problems. The term is the prevalent one for these functions in industrial automation environments but is also used for these functions in other environment vehicle guidance.
Lighting or illumination is the deliberate use of light to achieve practical or aesthetic effects. Lighting includes the use of both artificial light sources like lamps and light fixtures, as well as natural illumination by capturing daylight. Daylighting is sometimes used as the main source of light during daytime in buildings. This can save energy in place of using artificial lighting, which represents a major component of energy consumption in buildings. Proper lighting can enhance task performance, improve the appearance of an area, or have positive psychological effects on occupants.
Web colors are colors used in displaying web pages on the World Wide Web, and the methods for describing and specifying those colors. Colors may be specified as an RGB triplet or in hexadecimal format or according to their common English names in some cases. A color tool or other graphics software is often used to generate color values. In some uses, hexadecimal color codes are specified with notation using a leading number sign (#). A color is specified according to the intensity of its red, green and blue components, each represented by eight bits. Thus, there are 24 bits used to specify a web color within the sRGB gamut, and 16,777,216 colors that may be so specified.
Accessibility is the design of products, devices, services, vehicles, or environments so as to be usable by people with disabilities. The concept of accessible design and practice of accessible development ensures both "direct access" and "indirect access" meaning compatibility with a person's assistive technology.
An emergency exit in a structure is a special exit for emergencies such as a fire or other emergencies; the combined use of regular and special exits allows for faster evacuation, while it also provides an alternative if the route to the regular exit is blocked.
Universal design is the design of buildings, products or environments to make them accessible to people, regardless of age, disability or other factors. It addresses common barriers to participation by creating things that can be used by the maximum number of people possible. Curb cuts or sidewalk ramps, which are essential for people in wheelchairs but also used by all, are a common example of universal design.
Web accessibility, or eAccessibility, is the inclusive practice of ensuring there are no barriers that prevent interaction with, or access to, websites on the World Wide Web by people with physical disabilities, situational disabilities, and socio-economic restrictions on bandwidth and speed. When sites are correctly designed, developed and edited, more users have equal access to information and functionality.
Architectural lighting design is a field of work or study that is concerned with the design of lighting systems within the built environment, both interior and exterior. It can include manipulation and design of both daylight and electric light or both, to serve human needs.
Clearview, also known as Clearview Hwy, is the name of a humanist sans-serif typeface family for guide signs used on roads in the United States, Canada, Indonesia, the Philippines, Israel, Brazil and Sri Lanka. It was developed by independent researchers with the help of the Texas Transportation Institute and the Pennsylvania Transportation Institute, under the supervision of the Federal Highway Administration (FHWA). It was once expected to replace the FHWA typefaces in many applications, although newer studies of its effectiveness have called its benefits into question.
Building regulations in the United Kingdom are statutory instruments or statutory regulations that seek to ensure that the policies set out in the relevant legislation are carried out. Building regulations approval is required for most building work in the UK. Building regulations that apply across England and Wales were set out in the Building Act 1984 while those that apply across Scotland are set out in the Building (Scotland) Act 2003. The Act in England and Wales permits detailed regulations to be made by the Secretary of State. The regulations made under the Act have been periodically updated, rewritten or consolidated, with the Building Regulations 2010 having recently been superseded by the Building Safety Act 2022.
Tactile paving is a system of textured ground surface indicators found at roadsides, by and on stairs, and on railway station platforms, to assist pedestrians who are vision impaired.
Solar gain is the increase in thermal energy of a space, object or structure as it absorbs incident solar radiation. The amount of solar gain a space experiences is a function of the total incident solar irradiance and of the ability of any intervening material to transmit or resist the radiation.
The term "ADA Signs" has come into common use in the architectural, construction and signage industries with the advent of the Americans With Disabilities Act, or ADA. The Americans with Disabilities Act regulates accessibility; and includes requirements for signage that is conveniently located and easy to read both visually and through tactile touch.
The Rail Vehicle Accessibility Regulations 2010 is a Statutory Instrument in the United Kingdom. It aims to set standards designed to improve accessibility for disabled people on light rail passenger vehicles.
An exit sign is a pictogram or short text in a public facility denoting the location of the closest emergency exit to be used in case of fire or other emergency that requires rapid evacuation. Most relevant codes require exit signs to be permanently lit at all times.
A color appearance model (CAM) is a mathematical model that seeks to describe the perceptual aspects of human color vision, i.e. viewing conditions under which the appearance of a color does not tally with the corresponding physical measurement of the stimulus source.
Data visualization achieves its significance today due to information technology: big data processed in computers with capable visualization software, combined with statistical techniques and color coding on electronic displays. This article is about color coding in data visualization.