Lighting

Lighting is an essential aspect of home furnishings that also makes interiors more pleasant and allows tasks and activities to be completed much more easily.
Lighting energy and therefore, consumer cost, is a necessary consideration. Lamp is the technical term for what we call commonly a light bulb. A luminaire is the technical term for what is commonly called a lamp or fixture, which is a complete lighting unit. It includes the lamp holder, power connection, and any internal devices such as reflectors. Purposes of Lighting
The purposes of residential lighting are: 1. Ambient lighting- needed to perform routine activities 2. Task lighting- needed to perform specific tasks such as reading 3. Decorative lighting- needed to create an aesthetically pleasing environment
All three types of lighting are frequently combined in a space, and their purposes may overlap as required by the time of day or the uses of the room.
Ambient Lighting- is also referred to as general lighting. It provides uniform light for general purposes but not enough for specific tasks. Ambient light can be direct or indirect. Direct- when direct light is used, nearly 90-100 percent of the light is directed toward the surface to be lit. The direct light shines directly downward from the luminaire. Downlights are fixtures that are installed on the ceiling or wall to cast light below. If the downlights are directed against the wall, they are called wall washers. Recessed, ceiling- mounted or suspended luminaires are used for direct general lighting. Indirect- when indirect light is used, 90 to 100 percent of the light is redirected toward the surface to be lit. This is sometimes called reflected light. The indirect light shines against a surface and is reflected into the space indirectly. It normally produces a softer effect then direct light. Two methods are an uplight that casts light unto the ceiling and is reflected back into the room or the placement of luminaires recessed into the ceiling around the perimeter of the room. The light is directed toward the walls and “washes” them with light.
Task Lighting- improves visual clarity and helps prevent fatigue. It directs a pool of light where it is needed for activities, such as hobbies, reading, writing, word processing, preparing food, eating, and grooming. The source of light should not be seen. Task lighting may be portable or mounted. Examples of portable are table lamps and floor lamps.. Examples of mounted are track lights, spotlights, or strips of lights.
Decorative Lighting- there are two types, accent and mood.

Accent- sometimes called special emphasis lighting. It highlights an area of space , such as a piece of art or an accessory. It gives greater importance to the room. Track lighting is an example when placed above a painting. Accent lighting is usually used in dining rooms and living rooms.

Mood- creates not only visual interest but also an air of comfort. It is usually soft and mellow. Low lighting from a table lamp or flickering light from a fireplace are examples. Mood lighting can affect a person’s sense of well-being both positively or negatively. Low lighting- intimacy and intrigue, relaxation and privacy, sense of security, diminished eyestrain, can cause feelings of depression and fear Colored lighting- warm white and soft warm- colored lights- welcoming and uplifting, intense colored lights can cause eyestrain, cool white lights and cool-colored lights are more restful, but can become depressing. Large areas of bright light- produce a surge of energy but can cause fatigue after extended exposure, can cause boredom. Moderately bright light- generates an overall feeling of well-being Lighting as an Art Form- The light source and the luminaire can be creatively developed into art forms that are used as decorative lighting in the home. One may etch acrylic sheets that can be lit to create patterns of light. Pipes can conduct light. Colored lights can be inserted into the pipes which can be formed into many shapes. Wine bottles can hold candles or can be made into fixtures.

Lighting for Special Needs- People with poor vision have special lighting needs. The elderly may have a diminished perception of color, depth, visual acuity, and the size of visual field. Studies have shown that a person 60 years old needs twice the amount of light to do the same task of a 30 year old. Special reading lamps are being developed to help the elderly. Dimmers are useful to help individuals adjust the level of light to their personal needs. A dimmer is a switch that allows the amount of light to be increased or decreased of the light’s brightness. Other techniques that can help people with limited vision are accent lighting to highlight switches, electrical outlets, and keyholes, as well as lights at steps, pathways, and doorsills.

Controlling Glare – Glare is excessive light that causes irritation or fatigue. There are three types of glare: direct, reflecting, and veiled glare. Direct glare- occurs when a bright light or inadequately shielded light is in field of view. An accent light or a light in the center of the room can produce direct glare. It can also be strong sunlight. Reflecting glare- is when something shiny is reflected in the area of the task. It can be light reflecting in a television screen or a computer monitor screen. Veiling glare- is caused by light that reflects off a surface and causes a blind spot. The reflected images are seen rather than the task. It is caused by incorrect placement of the lighting source.
Both natural light and artificial light can cause glare. Glare from natural light can be controlled by window treatments. Glare from artificial light can be adjusted by reducing wattage, adjusting the direction of the light, are some of the methods.

Categories of Light

There are two main categories of light- natural and artificial.
Natural Light- has two main forms- sunlight and combustion light.

Sunlight- The primary source of natural light is the sun. The sun provides warmth and psychological benefits. The disadvantages of it as a source of illumination are: 1. There is excessive glare 2. There is excessive heat that can make a room feel uncomfortable 3. Direct sunlight can fade fabrics 4. Long term exposure to sunlight can lead to skin damage 5. Sunlight cannot help illuminate during evening hours Combustion- is the second source of natural light. Gas lights, fireplaces, and candles are all sources of combustion light. These are usually used for decoration.

Artificial Light- is usually used to create moods and emphasis and to focus attention. Artificial light is available in a range of sizes, shapes, and colors. One of the determinates on deciding what type of lamp to select is: 1.Color 2. Decorative effects 3. Energy consumption 4. Length of life or hours expected 5. Psychological effects 6. Quantity of light

One must be careful to avoid metameric shift, the changing of a color’s appearance under different lighting conditions. This can occur when viewing under artificial and natural light.

Two primary kinds of artificial indoor lighting are incandescent lamps and electric or gaseous –discharge lamps. Incandescent lamps are used in the home. Fluorescent lamps are examples of gas-discharge lamps used outdoors and in non-residential settings.

Incandescent lamps- heating a metal with an electrical current until it glows produces incandescent light. Incandescent light is warm, mellow, and flattering. It is similar to natural sunlight. It is commonly used for ceiling lights and portable fixtures. Wattage is the unit for measuring electricity consumed by a lamp. Lamps or light bulbs m, are categorized by their wattage. Lumens are a measure of the amount of light produced by a lamp or light source. The efficiency of a lamp is rated as the number of lumens produced per watt of electricity consumed. Incandescent lamps form bright highlights and cast sharp shadows. They use a lot of energy. The disadvantages to incandescent lighting are that they are costly and produce heat. The lamps wear out quickly and are discarded. The finish of the lamp glass determines the brightness and appearance of the light. Lamps may be clear or frosted. The light is intense and bright in a clear lamp while the light tends to be soft and diffused in a frosted lamp. Incandescent lamps are either standard or tungsten halogen. Standard incandescent lamps have argon or nitrogen gas around the filament.
Halogen lamps have halogen gas around the tungsten filament. As the tungsten burns off, the halogen reacts with the tungsten to create a bright light. The tungsten halogen lamps cost more but last longer, burn brighter and resemble natural sunlight more.

Gaseous-discharge lamps- are also called electric-discharge lamps. They produce light when an electric current or arc passes through a gas vapor sealed in a glass tube. A ballast is usually installed between the power and the lamp to regulate the amount and provide the proper starting voltage.
Fluorescent lamps were developed in the 1930’s. It is the most popular low-pressure electric-discharge lamp. The fluorescent lamp produces light when an arc passes between two electrodes inside a glass tube filled with very low-pressure mercury vapor. There is a phosphorus coating on the inside of the tube. The arc produces ultraviolet radiation that activates the coating, causing the phosphorus to glow. Fluorescent light is excellent for general lighting because it is even and creates no shadows. It provides clear light. They are used in commercial settings. In the home, they are used in offices, hobby rooms, under the cabinet lighting in the kitchen and in bathrooms.
Fluorescent lamps are more expensive than incandescent lamps but require less energy and last longer. The lamps come in both warm and cool colors. When compared to incandescent lamps, the advantages of fluorescent lamps are:
1. They last 10 to 15 times as long
2. Produce about 4 times as much light per watt, so more energy efficient
3. Produce almost no heat
4. Give off diffuse shadowless light that promotes good vision
5. Produce less glare
The disadvantage is that fluorescent lamps ceate a flat, monotonous lighting effect. Some of the colors of fluorescent lamps are not complementary to skin tones. The fluorescent lamps can hum or flicker that tend to be annoying.

Other types of Artificial Lighting- The other types of artificial lighting include cold cathode, fiber optic, laser, and neon.

Cold Cathode- Can be shaped like a neon lamp but operates like a rapid-start fluorescent. They have a very long life.
Fiber Optic- Thin glass or plastic fibers that produce intense pinpoints of light. They are used for special effects.
Laser- Light amplification by simulated emission or radiation. The beams can be dangerous, causing skin burns and damage to the retina of a person who looks directly at the beam.
Neon- A type of electrical- discharge lamp used for decorative or display purposes. They can be noisy and fragile.

Luminaires

A luminaire, or fixture, is the housing for the lamp. The shape and size of the luminaire can determine the shape and direction of the light beam.

Structural Luminaires- are sometimes referred to as architectural lighting. This type of lighting is permantly installed and includes wall and ceiling fixtures that are affixed to permanent wiring. There are six types of structural luminaires: recessed, surface- mounted, suspended, luminous, track-mounted, and built in. Recessed luminaires- are mounted above the ceiling line and are usually flush with the ceiling. They provide direct light. They are good for general lighting, wall lighting, and accent lighting.

Surface-mounted luminaires- can be attached to either wall or the ceiling. Ceiling mounted can direct the bean of light in pattern or focus it in one direction. A wall- mounted luminaire is called a sconce. They provide direct, indirect, or diffuse light. They are mainly used for decorative purposes.

Suspended luminaires- are sometimes called pendant luminaires. They can be suspended below the ceiling and produce direct, indirect, or diffuse light. They can either be functional like a suspended fluorescent lamp or be very decorative like a elaborate chandelier in a dining room.

Luminous panels- are strips of lights with glass or plastic translucent panels placed over them. They can be inset into floor ceilings, or walls. They are frequently used in kitchen ceilings.

Track- mounted luminaires- is very flexible and can be used in a wide variety of locations. It has two parts, the track which is an electrified holder that can be cut to many size, and the fixtures, which come in many sizes, shapes, and finishes. It can be recessed in the ceiling or attached to the ceiling or wall.

Built-in luminaires- also called spatially-integrated lighting. This is lighting that is integral to the construction of the building. An advantage of built-in luminaires is that the brightness can be controlled without creating glare. There are seven varieties of built-ins: 1. Cornice lighting- a board or opaque shield is attached to the ceiling near the wall. The light washes down onto a wall. 2. Cove lighting- a trough is mounted on the wall close to the ceiling. The light fixture is mounted on the wall within the trough. The light washes up and deflects off the ceiling. 3. Valence lighting- The light fixture and opaque shield are mounted at the top of a window above drapes or other window treatments. The light washes the window treatment and the ceiling if the valence is not covered. 4. Bracket Lighting- is similar to valence lighting except that it is not mounted over a window treatment. 5. Soffit Lighting- is generally placed over a work area, as in kitchen or bathroom. It can provide a high level of direct light. The light is directed downward, frequently from an overhead cabinet. 6. Toe- mold lighting- is sometimes called base lighting. A strip of lights is placed against or very near the floor where a deflector directs the light. 7. Specialty built-in lighting- has the important benefit of increased safety and easy access in the dark. Three examples are: riser lighting- mounted under a stair tread, toe-kick lighting- mounted under cabinets, handrail lighting- mounted under handrails.

Portable Luminaires- are sometimes called nonarchitectural lighting. They include lighting that is plugged into an electrical outlet such as floor and table lamps. They are limited by the length of their cords so that they are normally used near furniture. The height of the lamp and the width of the shade determine the usefulness of the lamp.

Selection of Lamps and Luminaires

Selection of lamps and luminaires require attention to both aesthetics and function. Some general recommendations for selection include the following: If a room is used for an activity, select the correct lighting for the activity first and then select the light for the rest of the room Areas for relaxation should be softly lit Areas used for vigorous activity should be brightly lit Outlets must be placed every 6 to 12 feet along a wall for portable luminaire

Lighting recommendations for specific rooms: Entrance area- diffused lighting from ceiling or wall sconces to create a warm, inviting atmosphere
Living room and family rooms- combination of both direct and indirect light, a dimmer can be used to control the brightness
Dining Rooms- should be lit to emphasize the table and enhance the china, silver and crystal
Kitchens- work areas should be well lit
Bathrooms- ambient light from a ceiling fixture and strip lighting around the mirrors.
Bedrooms- ambient lighting with dimmers, nightstands with reading lights
Hallways- Ambient lighting from glare-free ceiling or wall fixtures
Stairways- well lit for safety with ceiling or wall fixtures that direct the light downward

Selection of Chandeliers

Chandeliers are normally expensive focal points of a dining room. The size of the chandelier should be in proportion to the size of the table and the room. Other things to think of when selecting one is: Diameter of the chandelier should be in inches what the diagonal of the room in feet is. Chandelier should be small enough so that no one hit their heads when getting up- about 12 inches smaller than table Rectangular table should have a chandelier no more than 2/3 the length of the table Most dining room chandeliers are hung 30 inches above the table

Care of Lamps and Luminaires

All lamps and luminaires should be cleaned regularly to eliminate the dust and dirt that obscures light. Lampshades attract dust and need frequent cleaning. All wiring should be checked frequently to eliminate dangerous situations.

Environmental Issues

The most important issue related to lighting is the consumption of energy. There are two main ways to reduce the amount of energy- purchase more efficient lamps and fixtures and/or use less electricity.

Energy- Efficient Lighting- use fluorescent lighting in place of incandescent lighting when possible. Fluorescent lamps use 1/3 to 1/5 the energy of incandescent bulbs. In portable luminaires, use circular- fluorescent (CF) lamps that can be screwed in. The CF lamp can last as long as 10 average incandescent lamps and an 18 watt fluorescent lamp gives light equal to a 75 watt incandescent lamp. As of 2012, the flood or spot lamps above 65 watt are no longer being manufactured. You will only find halogen or CF bulbs.

Lighting Energy- Conservation Practices – The following are easy methods to reduce energy consumption and your utility bill: Turn off all lights when not in use Only use light where it is needed. Use portable luminaires with fewer lamps and lower wattage than ambient light Use dimmers to control and reduce wattage Supplement natural light with artificial light only when necessary Select light colored surfaces and textures that do not absorb light Use a single higher wattage lamp instead of several lower wattage lamps Replace existing bulbs with lower wattage bulbs