14 TYPES OF LIGHTING

M.R. Thilagam

OBJECTIVES

1. To understand the importance of lighting.
2. To gain knowledge on measurement and requirements of lighting
3. To become aware on the types of lighting

INTRODUCTION

Light has been always considered sacred and special in our culture. It is the primary requisite of life, basic of all living system and an important element for life. Any form, colour or texture, nor any enclosure of interior space would be visible only with the help of adequate lighting. Lighting a space is an important element in determining the beauty and comfort of the home.

1. A) IMPORTANT OF LIGHTING:

The purpose of a lighting design is to illuminate the interior environment, and allow the users to perform tasks with appropriate speed, accuracy and comfort home. A well-lighted room can ease tensions, help to create harmony, make reading and TV watching a greater pleasure and heighten the enjoyment of furniture, painting, and rugs. Poor lighting can spoil the over-all effect of the most expensively decorated room, while proper illumination can make a simply decorated room seem far more exciting than its budget might suggest. Good and efficient lighting is essential for every home and vast improvements have been made during recent years, both in artificial lighting and in making the best use of natural lighting. Artificial light becomes primary in homes, where most people spend much of their time after dark. Thus is an important part of every home and one should take utmost care for the lights they arrange in room.

Light is an important element of interior design and effect of the interior whether aesthetic, practical, or technical are implied by the use of light. When well used, light works its magic, creating atmosphere, camouflaging and enhancing the areas and facilitating practical task.

It makes things visible and sets a visible medium. Light is much more than just an utility.

It can affect us and in the way we sense the world more than any other feature in our homes. Lighting sets mood and creates impression. It provides safe circulation within the space. It is essential to make a space both enjoyable and functional. Lighting encourages a feeling of relaxation and comfort. It creates a sense of spaciousness. It profoundly affects the way people feel, work and interact and is the key to efficient building design. Lighting is one of the most important aspects for successful interior design. Good lighting supports convenience, comfort, favourable emotional reactions and also affects the perception of any room.

1. B) MEASUREMENT OF LIGHTING

Foot candle as a basic unit of illumination. It is a measure of the amount of light falling on a surface. One foot candle is equal to one lumen spread evenly over an area of one square foot. Pile (2005) explains foot-lambert as a basic unit of brightness, measuring the amount of the light reflected from a surface. One foot – lambert is equal to one lumen emitted by an area of one square foot.

Lighting requirement recommended for various activities is given below:

                                 Table 1: Recommended foot-candles for residential activities

                                                  Table II : Lumen output of lam

C) SOURCES OF LIGHT

There are two sources through which we obtain light

1. a) natural light and b) artificial light.

Natural light

Natural lighting is when we harness the light given out by the natural elements in the environment such as that of sun and moon. Natural light may be provided by wall, windows, ceiling windows or roof windows. Thus, day light is such an important factor in the appearance of a room that no plan of decoration should be made without considering the exposure, number of windows, amount of sunshine that enters the room, trees and plants that cut down the light and what season of the year the room is used most.

Sources of Artificial lighting

There are two common sources of artificial light – the incandescent bulb and the fluorescent tube. Plat 1 shows incandescent and fluorescent bulbs used in the interiors. Light bulbs and tubes can be grouped in general categories according to the way they produce light. They are installed in ceiling fixtures, floor, and structural light designs that direct the light to where it is to be used.

• Incandescent light

In an incandescent lamp, light is produced by heating a tungsten filament which is highly resistant with an electric current until it glows. Incandescent light contains a continuous, warm, mellow colour spectrum. It produces heat and is costly. Incandescent lighting is used in ceiling and portable fixtures such as table lamps. This lighting is flattering and best for warm mood lighting. These lamps are available in a wide range of wattages. a type of incandescent light is the tungsten halogen lamp. The filament of the small lamp is surrounded with halogen gas. As the tungsten burns off, the halogen reacts with the tungsten, creating a bright light. This type of light enables one to direct light to a certain area and to intensify the light by placing the bulb inside a reflective (PAR) lamp. Low voltage lighting has a built-in reflector with a tungsten halogen bulb that produces superior accent lighting or spotlighting.

• Fluorescent light

In a fluorescent lamp, light is produced by an arc between two electrodes inside a glass tube filled with very low pressure mercury vapour. The arc or discharge produces ultra violet (invisible) radiations in wavelength that excite or activate the white powder (phosphorus crystals) lining the lamp. Phosphorous fluoresces (glows), convert the ultra violet energy into visible light energy. Fluorescent light is a relatively shadow less, even light, making it ideal for general lighting of environments where task lighting would be impractical or undesirable. In homes, fluorescent lighting is most commonly used in luminous ceiling panels, recessed into a drop ceiling and covered with texture, translucent panels. Fluorescent lights are also commonly used in under the cabinet lighting over counters, in bathroom lighting and over work surfaces in hobby rooms or offices. This types of even, clear light provides an environment where work can take place for hours without causing fatigue.

Compact fluorescent lamps (CFL) are initially more expensive. They consume one-fifth of the power and has a life time up to thirteen times longer than incandescent lamps. CF lamps also offer a choice of colours and degrees of “warmth”.

Dimmable fluorescent lighting system consists of electronic dimming ballast, control wiring, power wiring, a wall-box dimmer switch, and dimmable fluorescent fixtures.

Coloured fluorescent light is cold – cathode lighting, commonly called neon lamps.

These use different gases or vapours to produce colours.

High intensity discharge (HID) lamps are high-pressure electric discharge lamps are commonly available in three types, each with different characteristics, depending upon the gas vapour inside and the phosphor coating. In general, their advantages include: High efficacy, long life and lamp shade similar to incandescent. HID lamps have been used primarily for industrial applications and outdoor lighting (http://ezinarticles.com).

D)  TYPES OF LIGHTING LED lights

A light emitting diode is a two – lead semiconductor light source. It is a p-n junction diode which emits light when activate4d. Early LEDs were often sued as indicator lamps for electronic devices, replacing small incandescent bulbs, but recently LEDs permit them to be used in environmental and task lighting. LEDs have many advantages over incandescent light sources including lower energy consumption, longer life time, improved physical robustness, smaller size, and faster switching. They are more energy efficient and have fewer environmental concerns linked to their disposal. However they are more expensive than CF lamps. From the point view of service they provide, three types of lighting are felt necessary. Namely, general, task and accent lighting.

1)   General / ambient lighting

Light which are used generally to light up the room are known as ambient or general lighting like the wall lights, chandeliers etc. It must be sufficient to ensure safety of movement and should be of high level for simple tasks. It covers undefined areas of a room with a soft level of light. The general lighting should be provided in various intensities. Ambient lighting provides a diffused spread of illumination which comes from an indirect source of lighting.

2) Task lighting

It is obtained with a fixture that illuminates a work surface where a visual activity takes place, with direct light. Task lights offer high intensity lighting without high general illumination. Task light is produced in particular places, usually by portable floor and table lamps, but also by straight or curved lighted rods and by lights behind ground glass that is flush with the wall.

3) Accent lighting:

Accent lighting chiefly fills an aesthetic need – a spotlight dramatizes or highlights an art object. Accent sources given local rather than general illumination. They are supplementary to the general light sources. The effect of accent lighting is instantly appreciated when one enters a room with much sparkling light. down-lighters, up-lighters and wall washers can also become accent lights.

Types of lighting fixtures

1a) Movable light fixtures

The movable light fixtures are table lamps, floor lamps, and small specialty lamps. They are easy to buy, easy to take along when one moves. Table lamps serve as source of light. They also represent individuality and style, at the same time. It is available in different varieties. Mobility and ease of installation add on to the appeal of such lamps. Floor lamps offer great flexibility. The traditional floor lamp serves as a reading light or as a source of soft ambient light. Recessed ceiling fixtures are used to provide illumination without the intrusion of a visible fixture especially in rooms with low ceiling and sleek lines. In areas where there is enough space between the ceiling and the roof above recessed fixtures are used.

1b) Surface-mounted fixtures

Surface-mounted fixtures are integral to most home lighting designs as they are installed either on walls or on the ceilings. They provide general illumination in traffic areas such as landings, entries and hall ways where safety is a consideration. Kitchen, bathrooms and workshops benefit from the added light from ceiling fixture when used along with task lighting on work surfaces. Sparkle and style in high ceiling entries and above dining and game tables are added using Chandeliers and pendant fixtures. These decorative fixtures could provide direct or diffused light or a combination of the two.

Mini-lights and strip-lights: For fun as well as for effective task lighting Mini-lights and strip lights are sued. In order to provide very good effect in highlighting high windows and other architectural features this type of lighting could be used as they also add colour along with splash of light.

Track lighting offers great versatility of installation as they are available in varying lengths.

Architectural lighting includes luminous panels, built-in indirect lighting, recessed and adjustable fixtures and surface-mounted and suspended fixtures.

Luminous panels are strips or lines of lights, usually fluorescent, over which glowing glass or plastic translucent panels are placed. A light placed behind a built-in or portable feature represent built-in indirect lighting. Types of indirect lighting placed behind deflectors include the following:

Cornice lighting: A light behind a board mounted into the ceiling washes light down onto the wall.

Valance lighting: A light used over the top of windows washes both the ceiling and the window treatment.

Bracket lighting (Up and Down): Valance lighting mounted lower on the wall washes the upper (and perhaps lower) wall with the light.

Bracket lighting (up only): A light placed just below the ceiling has the board or deflector beneath it.

Soffit lighting (in a kitchen): A light built into the soffit shines downward from the top of the cabinet overhead. Soffit lighting (in a bath): Soffit lighting provides even illumination for personal grooming.

Fixed and adjustable lighting: This includes various luminaries that are “fixed” or set into the ceiling called recessed luminaries and those that are adjustable. Adjustable luminaries can be recessed or surface mounted.

Recessed down light: Canisters set into the ceiling cast pots of light downward.

2. Lighting fixtures providing different types of lighting

Though the type of lighting required is different, it is the kind of fixture or the shades of the lamps that provide different types of lighting – direct, indirect, direct – indirect, semi-direct and semi indirect.

2a) Direct lighting: Greatest quantity of light is obtained by a direct fixture. It concentrates the light at the desired surface and a minimum amount of lighting is lost in transmission. Down-lightings are fittings designed to direct light straight downwards; the effect is to evenly illuminate the horizontal surface below.

2b) Indirect light: Indirect lighting is produced by a light source that is hidden. The light is directed to a ceiling, to a cove, or to another surface from which it is reflected back into the room. Indirect lighting creates almost no shadows when it is used next to the ceiling, and it is ideal for general illumination. Indirect lighting reflected down from the ceiling tends to raise the ceiling height by created a visual illusion.

2c) Direct-indirect lighting or general diffused: A fixture that has bulbs both inside and outside the reflector, as some table and floor lamps do, produce a direct-indirect, diffused light.

2d) Semi-direct lighting: In semi-direct fixtures sixty per cent of the light is directed down to the work surface and the remaining amount is directed upward.

2e) Semi-indirect lighting: Semi-indirect lighting directs 60-90% of the light towards the ceiling and an upper wall, using the ceiling as the main reflective source, the other 40% to 10% is directed toward the work place.

E)  FACTORS AFFECTING ILLUMINATION

Our ability to see well, is affected not only by the amount of light available for illumination, but also by the following factors.

•  Brightness
• Contrast
•   Glare
•   Diffusions
•   Colour

Brightness: It refers to how much light energy is reflected by a surface. The degree of brightness of an object is, inturn, depends on the colour value and texture of its surface.

Contrast: Contrast between an object and its background is especially critical for visual task that require the discrimination of shape and contour.

Glare: Glare is the transmission or reflection of light in such a way that the eye gets an unpleasant sensation. Lighting can produce two kinds of glare – discomfort and disability glare.

Discomfort galre may be caused by an over bright source of light or too much contrast between an object and its background.

Glare also results when bright light falls on polished or glossy surface and is reflected from that surface to the eye.

Diffusions: The soft light provided minimizes contrast and shadows. Diffused lighting is useful for general vision. However directional lighting relieve dullness by providing visual accents.

Colour: The interaction of light and colour is a subtle but powerful force in planning lighting for an interior. Colours containing a lot of white reflect larger amount of light and darker colour absorb light.

F)   REQUIREMENT OF AN IDEAL LIGHTING

Steadiness of the source of light: There should be no appreciable fluctuation or flickering of light which overstrains the eye so that the source of light remains stable. Elimination of glare: Glare of the vision is likely to occur if gas or incandescent electric lamps are used. It may be remedied by placing the source of light high above the level of the eye, so that it is not ordinarily seen, and screening the light by means of a suitable shade, or interposing frosted or opaque glass silk, celluloid, etc., to diffuse and soften the light, so that glare is eliminated.

Avoidance of shadows: Inconvenient shadows can be avoided by proper shading of the source of light, using light colours on walls and ceilings which reflect and diffuse light in all directions, and providing a general mild light to illuminate the entire room, and one or more stronger lights, in addition, in proper places for specific purpose such as reading, sewing, etc. Sufficient illumination to suit the nature of the visual task for the comfort of the eye and efficiency of the particular visual task, proper degree of illumination is required. Non-production of excessive heat is a great disadvantage in a tropical country like India, particularly in the summer. Therefore the light source should be properly shaded whether by natural or artificial means. Minimum consumption of oxygen from the air except the incandescent electric light, every other source necessarily consumes oxygen from the air. This factor needs to be kept in mind while choosing the kind of light for a room.

G.  FACTORS INFLUENCING SELECTION OF LIGHTING The various factors that influence their choice are as follows:

  1)Function: One of the primary considerations is how the fixture would direct the light. Make sure that directional fixtures have enough maximum bulb-wattage for the task performed.

2)Size: Fixtures on display will often look smaller in the store that they will in the homes. Make sure the right size is chosen.

3)Design: here personal preference and taste would guide the choice. Manufactures offer ‘families’ of fixtures available as spotlights, pendants, track lights and ceiling fixtures. This offers a sense of decorative continuity by using similar fixture.

4)Flexibility: Because tastes, habits and technology often change, flexibility is one important consideration. Movable or adjustable lamps are long time favorites.

5)Cost: purchase price and operating costs are very important in fixture selections.

6)Maintenance: to operate efficiently, all fixtures should be cleaned regularly. Using a fixture which is easy to clean and provide better accessibility towards changing light bulbs should be considered.

7)Space and atmosphere: The space to be lit and used should be objectively assed based on which quantum of light should be analyzed.

8)Focus and Detail: The main features to be highlighted in the room should be assessed. These might be architectural or decorative; one might equally consider what would be best left unlit.

9)Tasks: Activities to be performed in the room and requirement of special lighting should be taken into consideration.

10)Practicalities: Restrictions to the installation of new wiring should be taken into account.

11)Control: Finally technical details such as placement of control switch, member of switches and power points required in the room, requirement of dimmers, and different types of circuits needed must be considered.

H.  LIGHTING FOR DIFFERENT LOCATION / ACTIVITIES

The amount of light required, varies according to the needs or the functions of an area and rooms. In a residential area and commercial area, the need for lighting and the amount of lighting will be different from the place to place. These differences for the various areas are discussed in detail in the following paragraphs.

Entrance and passage lighting should provide good front door and porch lighting. The door itself, the keyhole, the ground immediately in front of door and the steps or steps leading up to it should be clearly visible. One can create a welcoming atmosphere by brightly lighting the entrance hall. A hall may have a direct or indirect ceiling light that can give brilliant, medium or subdued light as required.

Living room lighting: The main criterion of any living room is that it should be a relaxing, inviting space, flexible for all that goes on, but nevertheless with a definite style. The lighting in one’s living room would not be completed without some highlights on paintings or on the crystal in one’s cabinet. Apart from its stylish appeal, accent lighting also provides a certain amount of ambient light. Spotlights meet the need very well when used effectively.

Dining room lighting: A ceiling lighting fixture is sometimes the most practical solution for lighting a dining room. The use of low-level general illumination will create a serene atmosphere. Bright overhead lighting tends to have too harsh a character of a pleasant dining-room-lighting. A hidden spot light can be placed to throw extra light on the table. Candle light is pleasant for the dining table because of its softness to dinners and to the table appointments.

Bedroom lighting: Bedroom lighting must be planned with more attention to the needs of a specific user than lighting for general living areas. Apart from sleeping, the bed room introduces a multiplicity of lighting requirements such as for reading, either in bed or in an armchair, dressing in front of a long mirror, studying or writing letters, eating at a breakfast table, viewing television, sewing etc. General lighting is needed in a bedroom too for orientation purposes and in order to find things in cupboards.

Child’s room lighting: A child’s bedroom should be furnishing with a well-lighted desk. Long, harsh shadows as well as glaring, unscreened lamps should be avoided. Similarly, narrow-beam spotlights, which are often sued to provide decorative effects in other areas of the home, are not recommended in the children’s room.

Bathroom lighting: A general ceiling lighting may be sufficient for a bathroom. Several overhead fixtures could be provided for medium size or large size baths and especially for those with sectioned areas such as sub, shower and toilet. The most critical lighting in the mirror area of bath centre is the basic for good grooming. The most efficient to light up a person’s face is to use three fixtures, one on either side of the mirror and overhead.

Kitchen lighting: Genral lighting for a kitchen should be well distributed, uniform and as shadow less as possible special lighting for major work areas, pantry, wall cabinets or shelf mounted brackets can be installed as per the requirement.

Reading room lighting: Lamps must have a proper quality and quantity of illumination for maximum concentration and pleasure of reading. It should be placed so that the light falls comfortably on the open page. Powerful up lighters, down lighters, or the general lighting may be used with task lights as required.

Lighting the stairways: Stair ways should be well lit to prevent accidents. Switches at both ends should be provided for convenience. Utility / laundry areas need plenty of well-diffused general lighting. For added security, illumination on all the sides of the house is essential. Use of timers on interior lights make the home look occupied when the owneris away. The steps, paths, and driveways should well illuminated to make sure family members and guests are able to move about easily and safely. Lighting for TV, video games, and computers require low-level general lighting that does not wash out the screen’s image nor reflect into the viewer’s eyes.

Conference room lighting: The main objective of conference lighting is to illuminate every corner with minimal shadowing. The lighting should be otherwise cost-efficient, effective, power efficient and pleasing. Conference room is important room where there is a scope of ample lighting and designer lighting fixtures like ceiling and pendants with fluorescent lights would aesthetically bright up this room. To impart conference room a modern appeal track lighting fixtures can be fixed.

Restaurant lighting: Staggered height pendants could be considered to break up the plane and create an aesthetically pleasing environment in the entire room. This provides the continuity throughout the restaurant and a creative centerpiece in addition to general lighting.

Hotel reception lighting: Reception areas in hotels or businesses serve a multi-purpose function. It general illumination should be provided to compliment the staff behind the reception desk.

Conclusion

Lighting is an important aspect of comfortable living. Owners task and their knowledge in lighting reflect the type and amount of lighting provided in home. It is relatively easy to focus sufficient light on work surfaces and to provide for some kind of general illumination. But a balanced combination of natural and artificial light throughout the home or commercial space need thoughtful planning and its execution. That is a challenge for every individual. Theoretical knowledge with practical experience will help one to succeed in the venture of lighting an interior.

References:

1. Craig and Rush, Homes with Character
2. Dorothy Stepat – De van. Home Furnishings
3. Faulkner and Faulkner (1975), Inside Today’s Home, Holt, Rinehart and Winston, NewYork.
4. Gandotra.V, Shukul.M, and Jaiswal.N, (2011) Introduction to Interior Design and Decoration, Dominant Publishers and Distributors New Delhi.
5. Goldstein and Goldstein, Art in Everyday life, Prentice hall Inc . New Jersey