Crestron electronic GLPS-HSW-FT Grazing and Washing Surfaces, Switch and Dimmer Locations, Glare

Commercial Lighting Design Guide Appendix D

Grazing and Washing Surfaces

On walls or on the surface of an object, changing the way light is focused produces different effects. To emphasize a rough textured brick wall, graze the surface with light striking the surface at a sharp angle. To emphasize a smooth wall, wash the surface with light by striking the surface at a wider angle.

Switch and Dimmer Locations

The proper location for a switch or dimmer is a function of code requirements (the National Electrical Code establishes some specific locations where control devices are required) and common sense. For example, the code requires a wall switch adjacent to the door upon entry to a room. but you can also add a switch in a preferred location, such as next to the bed.

Another choice are motion sensors that automatically switch lights off when the room is empty, and they are especially efficient devices in spaces like garages, utility rooms and other spaces where lights are only needed occasionally and are often left on inadvertently.

Crestron offers the most technologically sophisticated products that permit handheld remote dimming, whole house master controls, and many other features.

Color Temperature

Color temperature is the color of the light source. By convention, yellow-red colors (like the flames of a fire) are considered warm, and blue-green colors (like light from an overcast sky) are considered cool. Color temperature is measured in Kelvin (K) temperature. Higher Kelvin temperatures (3600–5500 K) are considered cool and

lower Kelvin color temperatures (2700–3000 K) are considered warm. Cool light is preferred for visual tasks because it produces a higher contrast than warm light. Warm light is preferred for living spaces because it is more flattering to skin tones and clothing. A warm color temperature of 2700–3600 K is generally recommended for most indoor general and task lighting applications.

Color Rendition

Color rendition is the appearance of colors when illuminated by a light source. Color rendition is generally considered to be a more important lighting quality than color temperature. Most objects are not a single color, but a combination of many colors. Light sources that are deficient in certain colors may change the apparent color of an object. The Color Rendition Index (CRI) is a 1–100 scale that measures a light source's ability to render colors the same way sunlight does. The top value of the CRI scale (100) is based on illumination by a 100 watt incandescent light bulb. A light source with a CRI of 80 or higher is considered acceptable for most indoor residential applications.

Glare

Glare is primarily the result of relative placement of light sources and the objects viewed. Often, it is excessive brightness from a direct light source making it difficult to see. A bright object in front of a dark background usually causes glare. Bright lights reflecting off a television or computer screen or even a printed page produces glare. Intense light sources—such as bright incandescent lamps—are likely to produce more direct glare than large fluorescent lamps.

Doc 4775A 97