A Glossary of Home Lighting Terms

 

Language of Home Lighting

 
Accent Lighting - lighting that is used to accent or emphasize shapes, textures, finishes and or colors, as in a sculpture, window treatments, or any other object of interest.  Accent lighting creates a focus or foci of visual interest in a given space.  Accent lighting can also be used to direct the eye along a visual field or through a "path".  It is recommended that be effective, accent lighting should be a minimum of three times the amount of ambient light in the same area.

Ambient Lighting - also referred to a "general" lighting, ambient lighting is intended to fill the space with overall illumination providing enough for overall orientation and general task purposes.  The level of ambient light should be able to be managed to provide a range of brightness specific to the purpose of the space at a given time; e.g., bright perhaps for cleaning, but lower levels to create a more intimate or relaxed setting.

Chandelier - a light hung from the ceiling, most often in dining rooms, but they are also seen in entryways and large stairways, and serve both functional (lighting) and decorative (form) purposes.  The typical chandelier hangs 30-36" above the height of the table, and is slightly narrower than the table so as to avoid bumping it as you are seated at the table.

Collectible Lamps - a popular series of decorative table lamps wired to safely allow the user (including young children) to add contents or "treasurers" and display them accordingly.  Reported contents include sea shells, antique buttons, wine corks and bottle caps, marbles, small action figures, Christmas ornaments, Easter eggs - limited only by your imagination!

Color Rendering Index (CRI) - a measure of a light bulbs (lamp) ability to render colors accurately, where the sun (the most accurate) measures 100.  A measure of 85 is considered to be good.

Color Temperature - a measure of the color appearance of a light source using the Kelvin (K) standard.  Light sources with an index below 3200K are generally considered to appear, or to give off a "warm" light, while a light source with an index reading above 4000K are considered to emit a "cool" or "bluish" light.

Compact Fluorescent Lamp (CFL) - a generic name used for a wide range of small, single-ended fluorescent light bulbs (lamps) - often referred to as "energy efficient bulbs".  The light bulbs may be folded, or spiral glass tube designs with a color rendering index typically above 80 and a long life (typically > 8,000 hours).

Cove Lighting - a lighting design comprised of sources of light shielded or hidden by a ledge or recess and distributing light onto the ceiling, and, at times, over the upper part of a wall.  Cove lighting can often be seen in the high domed ceilings of cathedrals.

Dimmer - a mechanical device in the electrical circuit used to vary the brightness of the lamps in either mounted fixtures or portable table lamps.  Dimming controls allow the user to moderate the amount of lighting to suit the activity or "mood" of the space.  When used with mounted fixtures, the dimmer is part of the wall switch panel.  When applied to a table or floor lamp, the dimming feature can either be designed into the socket or achieved with a line switch on the light cord.

Downlight - a small, often recessed in the ceiling, fixture that directs or concentrates the light downward.

Filament - a tungsten wire that "incandesces" or lights up upon activated by an electric current; hence, an incandescent light bulb or lamp.

Fitter, Lampshade - See Lampshade fitter.

Finial - the decorative accent at the top of the lamp, also used to secure the lampshade onto the harp. Finials come in a wide range of styles and colors, and are often considered the "jewelry" of the lamp.

Fluorescent Lamp - a low-pressure mercury electric discharge light bulb (lamp) in which a phosphorous coating on the inside of the glass tubing transforms some of the ultraviolet energy created inside the tubing to visible light.

Footcandle - the amount of light striking a surface one foot away from a candle.

General Lighting - also known as ambient lighting, the goal of general lighting is to provide substantially uniform lighting through out a given space - not including lighting for specific purposes such as reading (task) lighting or accent lighting (artwork).

Halogen - a type of incandescent light bulb (lamp) that contains halogen gases (e.g., iodine, chlorine, bromine and fluorine), which slow the evaporation of the tungsten filament.  The glass tube or envelope which surrounds the filament of a halogen bulb should not be touched with bare hands.  The natural oil from human hands shortens the life of the halogen light bulb.

Hard Wired - the case in which the light fixture is permanently connected to an electrical source as in a ceiling or wall fixture.  The light fixture is not hard wired if its power comes through a cord and plug.

Hardback Lampshade - lampshades made by laminating a fabric or paper onto a plastic liner.  Each shade has a top ring and a bottom ring, and the laminated fabric is manufactured to attach to each ring, and then glued on one or more sides, forming the seam.  The inner plastic liner can be translucent or opaque, while the outer, visible fabric can be any type of woven fabric including linen, silk, satin, muslin, or one of many different types of parchments or paper.

Harp - the metal wire lamp part that fits into a saddle and supports the lampshade.  Harps come in 1/2" increments.  The size or height of the harp is totally dependent upon the lampshade selected for the lamp - the taller the shade, the taller the harp.  One important objective in selecting the correct harp is to ensure that the lampshade blocks from view the harp saddle and socket.

Harp Saddle - the metal wire lamp part that is mounted below the socket and into which the harp fits.

Hi / Lo Switch - a two light-level switch utilizing a diode to reduce the voltage coming in to the lamp.

Incandescent - a light bulb (lamp) in which light is produced as a result of an element heated to the point of incandescence by the passage of an electric current.

Lamp - a light source, typically incandescent, halogen or fluorescent. A lamp is most frequently referred to as a light bulb, or bulb.

Lampshade fitter - the means by which the lampshade is supported on the lamp. The most common fitter is called a "washer" fitter, a small washer shape supported in the middle top of the shade by three or four wires extending to the top sides of the shade.  A shade with a washer fitter is designed to sit on a harp. A shade with a clip fitter attaches to the lamp by means of a metal wire that fits or "clips" onto the light bulb; most shades with clip fitters are small so as to minimize the weight resting on the bulb. A lampshade with a uno fitter is designed to screw onto the end of a socket fitted to a downbridge lamp - or one in which the light bulb is pointed down. A lampshade with a chimney fitter is designed to be used for lampshades that are intended to sit on a hurricane - most commonly an electrified oil lamp.

Layers of Light - the technique used to fill a room with light while also accomplishing specific functional / design objectives.  Ambient, or general lighting is used to fill the space, while task lighting allow people to perform certain tasks.  Accent lighting is used to highlight or accent specific objects or spaces and decorative lighting is accomplished through the selection of attractive and complementary light sources.

LED - a light emitting diode is a small electronic device that lights up when electricity passes through it.  LED's are the newest technology to be introduced in residential lighting.  While still quite expensive, they are very energy efficient and long lived (30,000+ hours.).

Light Fixture - a complete lighting unit that includes a housing, one or more light bulbs (lamps) and a connection to a source of electrical power.

Line Voltage - the typical voltage coming out of the wall outlet in a residence.

Low Voltage - used in many high intensity lamps - particularly desk lamps and lamps using a halogen light bulb. Most low voltage lamps will require a transformer to be used in the residence.

Lumen - a unit of measure used to describe the amount of light emitted by a light source.

Opaque - a material that blocks the light in specific directions.  An example would be a metal shade or a dense paper.

Pendant - Pendant lights are typically suspended from the ceiling over a table (dining or game), or counter or other work area and can provide both task and ambient light.  Most often designed with metal or glass shades to avoid glare, pendant lights should be hung about 30" above the table or counter top.

Picture Lights - accent lights designed to highlight a work of art. Picture lights are designed to either hard-wire into the wall directly behind the artwork, or can be fixed to the frame and then plugged into a local outlet.

Portable Lamp - a table, floor or desk lamp which can be easily moved and plugged into an electrical outlet.

Recessed Downlight - a small light fixture recessed into the ceiling that focuses the light in a downward direction.

Sconce - an ornamental light fixture attached to the wall; they are often referred to as wall sconces.

Semi-Flush Ceiling Fixture - a light fixture that is suspended by 3-8" from the ceiling allowing light to reflect off the ceiling as well as provide some downlight through the glass or fabric shade.

Silk Lampshade - a lampshade whose liner is made from a fabric, while the outer fabric can be silk, satin, linen, or a variety of other fabrics. Each of these fabrics may be stretched, shirred or pleated. A silk shade has top and bottom rings that are connected by side wires, or struts. The placement and contour of the struts give the shade its shape and allow the material on the outside to follow the shape of the frame. Because a silk shade is built on a frame, it is possible to achieve a wide variety of shapes including bells, scallops, rounded corners, v-notches and gallery bottoms.

Socket - the object into which the light bulb (lamp) is inserted. A socket is a three-way or a simple on / off depending upon the number of contact points with the bulb; a single contact yields an on / off function while two contacts results in a three way function.  Some sockets are designed as hi / lo - a wire runs between the two contact points.  More expensive sockets - often electronic - are also available and function as continuous dimmers.

Task Lighting - lighting that is designed and installed to light a specific area where a task can be performed.

Torchiere Floor Lamp - is a lamp with a tall stand of wood or metal. Originally, torchieres were candelabra, usually with two or three lights. When it was first introduced in France towards the end of the 17th century the torchiere mounted one candle only, and when the number was doubled or tripled the improvement was regarded almost as a revolution in the lighting of large rooms.

Translucent - a material that transmits some visible light. Paper, frosted glass or a fabric are all examples of translucent materials.

Transparent - a material that transmits most, if not all, of the visible light incident upon it, with little distortion.

UL - Underwriter's Laboratory, Inc. is an independent, not-for-profit product safety testing and certification organization.  The UL symbol with the letters "US", and the letter "C", indicate that the lighting product is UL listed in both the United States and Canada.

Wall Grazing - a lighting term that refers to the effect of lighting certain wall surfaces such as draperies, stone, brick or a work of art (most often from above). Grazing creates high and low (shadows) levels of light on targeted surfaces.

Wall Swing Arm Lamp - a decorative light fixture affixed to the wall that is designed to swing out from the wall and provide task lighting to a specific area.

Wall Washing - a lighting technique that produces a relatively smooth and even illumination on the wall with no shadowing.

Wattage - the amount of electrical power consumed by a light fixture in "watts". One watt is equal to the power dissipated by 1 ampere of electrical current flowing across a resistance of 1 ohm, or the power produced by 1 ampere of electrical current under an electromotive force of 1 volt.

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