Maeka SanvictoresBSA-3B

1/8/20142014

RESEARCH #1LIGHTING

Basic Characteristics of Light Sources

By Scott Watson

Light sources such as incandescent lamps, halogens, fluorescents, LEDs and some others have

basic characteristics.  They also have their positive and negative aspects.  Actually, there are

different kinds of light sources in use all over the world.  None of them has actually proven to be

very suitable for all applications.  In this write-up, you’re going to learn more about the positive

and negative aspects of the lighting sources. This will help you to get more understanding

about LED lighting system.  Let’s have a look at some of the characteristics.

• Light Quality

This is basically the very first characteristic of many light sources.  The quality of the light

generated is very vital.  It shows how   good or bad a lighting source is.   Basically, two simple

measures are considered under the light quality characteristic.  They include Correlated Color

Temperature (CCT) and Color Rendering Index (CRI).  These two measures   offer a broad

overview of most light sources.   The CCT explains the color temperature of light sources.  For

instance, the yellow color is usually hotter than the red.  On the other hand, the CRI describes

the reproduction system of the various colors seen in light sources.  For instance, a CRI of 100

is perfect while a CRI of 82 is better than that of 60.

A typical incandescent bulb is known for having a CRI of 100 and a CCT of 2850K.    

Fluorescent bulbs are usually known for having varying levels of CRI and CCT.    A typical

fluorescent bulb may have a CRI of 82 and a CCT of 4100K.  This usually brings out the white

color in the bulb.

•  Efficacy 

The efficacy of the light sources also matters a lot.  This talks about their efficiency and how

much light they generate as well as their energy input.  When it comes to efficacy, the

incandescent lights are at the lowest ebb.  They simply serve as resistors.  A typical

incandescent bulb of 60W produced 830 lumens.  Higher incandescent bulbs   are also more

efficient than the low capacity ones.

Fluorescent bulbs are known to be higher in efficacy when compared to the incandescent

lamps.  A typical 4 ft fluorescent tube normally produces 2700 lumens for 32W. This amounts to

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an efficacy of 84 Lm/W.   However, an incandescent light can easily be plugged into a 120

VAC   which makes it very easy to use. But a fluorescent bulb requires a ballast to convert

power.  Most ballasts are known to be efficient but this depends on the level of their capacity in

carrying the tubes. 

•  Timing

Timing is yet another vital characteristic of light sources.  It covers the flicker and the turn on

time.   When it comes to turn on time, incandescent bulbs are known to be very simple.  When

power is applied to them, they can easily turn on immediately. They simply glow to the full

brightness.  On the other hand, fluorescent bulbs require extra timing.  They can be very

complex as well.    In most cases, a fluorescent bulb may take some minutes before coming

up.    The filament is usually preheated before the plasma arc is created to ensure the longevity

of the tube.  The preheat time usually takes up to 700msec.  When the tube is put on eventually,

it may take some minutes before coming to full brightness.  This delay is actually   one of the

major flaws of most fluorescent bulbs.  You may be delayed from seeing light when you use

such bulbs.  Some of the fluorescent bulbs do have lower start times. Sodium streetlights take

several minutes to turn on.  This is usually the case when they are put on at night. 

The HID lamps don’t usually turn on again after you put them off. You have to wait for about 10

to 15 minutes before you can put them on again. This can be very problematic especially when

there’s a sudden power outage. You may have to wait for several minutes to put the HID lamps

on.

Meanwhile, the term flicker refers to what happens   when a light turns off every time the AC line

passes through 0 volts.   Most incandescent lamps are usually known to be involved in this. 

However, you may not be able to notice this since they have filaments that take enough time to

cool down.  This makes the light change unnoticed.   The filament of an incandescent lamp

usually has a long thermal time constant.  You can discover this when you put off an

incandescent bulb. The light usually continues to showcase for some seconds after the turn off.

On the other hand, fluorescent tubes are known for extinguishing their plasma arc within 100 μ

sec. this is why a 10 KHz fluorescent tube has a 10% efficacy advantage over the one with

60Hz capacity.  This usually causes the fluorescent tube to turn off and on 50 or 60 times per

second.  In most cases, this produces an annoying flicker for most of the fluorescent bulbs.

LED lights also encounter such problems since they normally turn off faster than the ordinary

fluorescent tubes.

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• Dimming 

Most of the light sources usually have dimming problems.  Incandescent bulbs for instance drop

their CCT levels as they dim. This usually makes them to look redder in color. 

Fluorescent tubes also turn off when they become dim.  They usually perceive the missing

voltage as a blatant decrease in the average line voltage.  Again, if the voltage applied to the

ballast of a fluorescent tube is reduced, the arc current and the filament power will also be

reduced.  This shortens the lifetime of the tube. LEDs also have dimming issues.  They can be

designed to dim.

• Aging

Aging issues also occur in most of the light sources.  If one of multiple incandescent bulbs is

replaced in a fixture, this can indicate that the older bulbs have worn out over time.  The same

scenario is also seen in fluorescent bulbs and LEDs.  However, there’s a difference on aging

duration for all the light sources.  An incandescent bulb has a lifetime of 100 hours of usage.

Fluorescent bulbs have complex lifetime since their lifetime depends on how many hours they

are used as well as the on/off cycles used.  Basically, their lifetime stands at 10,000 hours of

usage.

LEDs have  longer lifetimes. This is because they are made of semiconductors that last for

years.  LEDs can serve for thousands of hours. Their average lifetime stands at 50,000 hours

In all, the above characteristics of light sources help you to know more about different kinds of

light systems. You can use them as background knowledge as you study more about LEDs and

their modes of operation. 

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Characteristics of light

The three most important characteristics of light are brightness, colour, and temperature. Brightness does not need much explanation, but colour and temperature are slightly more subtle concepts.

Light is electromagnetic radiation visible to the human eye. It consists of different wavelengths, which are perceived as different colours. Very long wavelengths are perceived as red, and very short ones as violet.

In between are orange, yellow, green, blue, and indigo. Beyond red are infra-red, microwaves, and radio waves; beyond violet, ultra-violet, X-rays, and gamma rays. Light that has a specific colour is emitted on a narrow band of wavelengths. For example, the yellow sodium streetlights only cover one wavelength - that emitted by excited sodium atoms. The same is true for most coloured light, such as the different-coloured flares used in fireworks, neon signs, Christmas lights, and so on. coloured light can only show up tonality (dark to light) in those colours that reflect the colour of the light. For example, a blue object in sodium light appears completely black: try it out for yourself if you don't believe me. However, a green object also reflects yellow light, so it will not look black - and an object that is exactly the same colour as the sodium lights will look identical to a white object.

White light is a combination of many wavelengths. It can show up tonality in all colours. However, the wavelengths may not be evenly distributed: the light may have a colour cast. For example, normal incandescent interior lighting is heavily weighted towards the orange-red end of the spectrum, and fluorescent light has a green cast. This is where white balancing comes in: it corrects for the distribution of wavelengths in the available light, and gives objects their "actual" colour. The human eye white-balances automatically - that's why we perceive a white sheet of paper as white even when it's lit by orange incandescent light... but if we photograph it in daylight white balance, the photo will appear orange. (Or vice versa: if we take a picture of a white sheet of paper in daylight using incandescent white balance, it will appear blue.)

The colour cast of white light can be unambiguously expressed as a temperature, usually in the Kelvin scale. It is a physical fact that if you heat an object to a given temperature, it will emit light with a certain colour cast, no matter what material the object is made of. However, this light is still "white" in the sense that it contains light of all wavelengths: therefore, it can reveal tonalities in all colours, and it is possible to correct for the colour cast by white balancing.

In a nutshell: you can white balance to correct colour casts in white light, but not for coloured light. There is no way of getting natural-looking colour in a scene lit by sodium streetlights: there simply aren't any blue or green photons to carry the information.

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Light sources

Light always starts on its journey from a light source. Light sources can be usefully classified into threetypes: direct or point-like, diffuse, and ambient. Each type of light source gives a picture specificcharacteristics. The fabled "good light" largely means a balanced mixture of the three.

Direct (point-like)

Direct light is emitted by a small, bright, and point-like source, and shines directly onto the subject. Some important point-like sources are the sun, a flash gun, and some forms of interior lighting. Direct light causes sharply defined, deep shadows and flattens out three-dimensional detail. A cylinder bathed in direct light will look very similar to a box next to it: the line dividing light and dark is sharp, and there's little or no gradation from fully lit to fully shadowed. Multiple point-like sources cast multiple shadows and result in multiple zones of varying darkness.

Diffuse

Diffuse light emanates from a large light-emitting or light-reflecting surface. It causes soft shadows and an even gradation from light to dark, emphasizing three-dimensionality and shape. A cylinder in diffuse light looks clearly cylindrical, with the fully shadowed areas completely black, the side directly facing the light source completely white, and the in-between areas shades of gray. The size and softness of the shadows depend on the size and distance of the light source: a diffuse light source that is very far away turns into a point-like light source.

Ambient

Ambient light is usually something of a theoretical concept: the sum of all the light that gets reflected around the scene. For example, there is always some light in the shadows even on the clearest day, due to reflection from surrounding objects. Ambient light casts no shadows; instead, it fills them in. A cylinder illuminated purely by ambient light (you would have to place it inside a milky-white sphere lit evenly from the outside) would appear completely featureless and flat - and so would a cube.

Light sources

When we view an opaque non luminous object, we see reflected light from the surfaces of the object. The total reflected light is the sum of the contributions from light sources and other reflecting surfaces in the scene Thus, a surface that is not directly exposed to a light source may still be visible if nearby objects are illuminated. Sometimes, light sources are referred to as light-emitting sources; and reflecting surfaces, such as the walls of a room, are termed light-reflecting sources . We will use the term light source to mean an object that is emitting radiant energy, such as a Light bulb or the sun. Aluminous object, in general, can be both a light source and a light reflector. For example, a plastic globe with a light bulb inside both emits and reflects

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light from the surface of the globe. Emitted light from the globe may then illuminate other objects in the vicinity.

The simplest model for a light emitter is a point source. Rays from the source then follow radially diverging paths from the source position; This light-source model is a reasonable approximation for sources whose dimensions are small compared to the size of objects in the scene. Sources, such as the sun, that are sufficiently far from the scene can be accurately modelled as point sources. A nearby source, such as the long fluorescent light is more accurately modelled as a distributed light source. In this case, the illumination effects cannot be approximated realistically with a point source, because the area of the source is not small compared to the surfaces in the scene. When light is incident on an opaque surface, part of it is reflected and part is absorbed. The amount of incident light reflected by a surface depending on the type of material. Shiny materials reflect more of the incident light, and dull surfaces absorb more of the incident light. Similarly, for an illuminated transparent surface, some of the incident light will be reflected and some will be transmitted through the material. Surfaces that are rough, or grainy, tend to scatter the reflected light in all directions. This scattered light is called diffuse reflection. A very rough matte surface produces primarily diffuse reflections, so that the surface appears equally bright from all viewing directions. In addition to diffuse reflection, light sources create highlights, or bright spots, called specular reflection. This highlighting effect is more pronounced on shiny surfaces than on dull surfaces.

Basic illumination models

Here we discuss simplified methods for calculating light intensities. The empirical models described in this section provide simple and fast methods for calculating surface intensity at a given point, and they produce reasonably good results for most scenes. Lighting calculations are based on the optical properties of surfaces, the background lighting conditions, and the light-source specifications. Optical parameters are used to set surface properties, such as glossy, matte, opaque, and transparent. This controls the amount of reflection and absorption of incident light. All light sources are considered to be point sources, specified with a coordinate position and an intensity value (color).

Ambient Light

A surface that is not exposed directly to a light source still will be visible it nearby objects are illuminated. In our basic illumination model, we can set a general level of brightness for a scene. This is a simple way to model the combination of light reflections from various surfaces to produce a uniform illumination called the ambient light, or background light. Ambient light has no spatial or directional characteristics. The amount of ambient light incident on each object is a constant for allsurfaces and over all directions. We can set the level for the ambient light in a scene with parameter I,ₐ and each surface is then illuminated with this constant value. The resulting reflected light is a constant for each surface, independent of the viewing direction and the spatial orientation of the surface. But the intensity of the reflected light for each surface depends on the optical properties of the surface; that is, how much of the incident energy is to be reflected and how much absorbed.

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Diffuse Reflection

Diffuse reflections are constant over each surface in a scene, independent of the viewing direction. The fractional amount of the incident light that is diffusely reflected can be set for each surface with parameter kd, the diffuse-reflection coefficient, or diffuse reflectivity. Parameter kd is assigned a constant value in the interval 0 to 1, according to the reflecting properties we want the surface to have. If we want a highly reflective surface, we set the value of kd near 1. This produces a bright surface with the intensity of the reflected light near that of the incident light. To simulate a surface that absorbs most of the incident light, we set the reflectivity to a value near 0.

Actually, parameter kd is a function of surface color, but for the time being we will assume kd is a constant. If a surface is exposed only to ambient light, we can express the intensity of the diffuse reflection at any point on the surface as

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TYPES OF LIGHT SOURCES

There are many types of light source. The sun and light from burning torches were the first light sources used to study optics. As a matter of fact, light emanating from

certain (exited) matter (e.g., iodine, chlorine, and mercury ions) ) still provides reference points in the optical spectrum.

One of the key components in optical communication is the monochromatic light source. In optical communications, light sources must be compact, monochromatic, stable, and long lasting (many years). In practice, there are no monochromatic light sources; there are merely light sources that generate light within a very narrow band of wavelengths. The light sources used in spectrography are neither practical nor economical in

communication. Stability of a light source implies constant intensity level (over time and

temperature variations) and constant wavelength (no drifts). Solid-state technology has made it possible to have such optical sources of light.

There are two different types of light source. The first type transmits a continuous wave (CW). Continuous emitting lasers and light-emitting diodes (LEDs) are examples of f CW

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light sources. This type of light source requires an external modulator at its optical output. In this arrangement, an electrical signal representing a data stream acts on the modulator that modulates the light passing through. The second type transmits

modulated light; that is, no external modulator is necessary. This type receives an electrical data

stream that directly modulates the light source. Lasers and LEDs are examples of modulated light sources.

Because light quality affects the color of wall finishes, curtains and upholstery, we find different types of light source to create varying qualities in light to suit the particular tasks and functions in the home.

Nowadays, a wide selection of artificial lighting is available, giving you the illumination choice from subtle to bright, diffused to focus.

Natural light: the most important light source that a designer should consider before planning a scheme for artificial light. Where does it enter your home, and how does it fall at different times of day? Windows, apertures, stores, curtains, blinds and shutters all offer possibilities for using daylight to create color, pattern and movement in a room.

Tungsten: since its introduction, the tungsten-filament incandescent has established itself as the universal household light bulb. It has some relevant advantages: being familiar and widely available, casts an attractive warm light, cheaply made and sold, don’t need a transformer and the glass bulb contains non-toxic gases.

Halogen: brighter and whiter than ordinary tungsten bulbs, it gives a fresh, clean light to complement the modern homes interior. It comes in two models: the mains-voltage halogen – which works well in track lights – and the low-voltage halogen – which are good for spots.

Mini-fluorescents: found in variety of sizes and wattages, these bulbs saves energy while fitting a wide range of domestic lighting fittings. Fluorescents went major developments into the

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last year making them cheaper on the long term than tungsten, easy dimmed and available in warmer light.

Fiber optics: currently expensive, fiber optics is most often used in galleries, clubs, hotels and museums for special effects. They have several advantages: they don’t generate heat except at the light source, suitable for water use; they can be bent and twisted; ideal for illuminating fragile object due to low temperature and low ultraviolet content.

Candlelight and imitations: candlelight has maintained its appeal long after the advent of electricity, not for the quantity of light it gives but for its quality. Nowadays and where the fire hazard is a public safety issue, there are various forms of bulb and fitting that imitates candles.

Technology and design progress is more and more presenting eco-friendly, economical, efficient light sources. There is no more excuses for the designer.

1.  LED - (light-emitting diode) technology is a new, low-maintenance, eco-friendly alternative to conventional lighting. As always,being a Lutron rep we are at the forefront of harnessing this innovation for both residential and commercial use .

Light Emitting Diodes (LEDs) produce light when voltage is applied to negatively charged semiconductors, causing electrons to combine and create a unit of light (photon). In simpler terms, an LED is a chemical chip embedded in a plastic capsule. Because they are small, several LEDs are sometimes combined to produce a single light bulb.

LED lighting in general is more efficient and longer lasting than any other type of light source, and it is being developed for more and more applications within the home. LEDs are currently popular in under-cabinet strips and some types of downlights.

To ensure that you are purchasing an LED bulb with good color quality and energy efficiency that is as good or better than fluorescent bulbs, look for the ENERGY STAR symbol.

2. Compact Flourescent - (with integrated ballast) These CFLs are a great energy-saving alternative to standard incandescent or halogen bulbs. These dimmers have HED™ technology that helps alleviate challenges associated with dimming compact fluorescent bulbs such as lights dropping out, turning off unexpectedly, and flickering.

Compact Fluorescent Lamps (CFLs) are small fluorescent bulbs that can be used in most types of lighting fixtures. The screw-in types can be used to replace incandescent lamps in standard lamp sockets

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3. Linear Fluorescent - (using separate ballast by Lutron) Lutron invented the world's first electronic dimming ballast over 30 years ago. Today, Lutron offers an vast selection of fluorescent dimming ballasts and controls that support complete fluorescent dimming systems.

4. Daylight - Sunlight is the one and only original renewable light and energy source. Lutron shading systems are designed to filter daylight to make a comfortable, inviting atmosphere that will reduce the heat and glare caused by too much sunlight.

ARTIFICIAL LIGHT SOURCES

Gaseous Discharge

This technology passes electricity through a gas, which excites the gas and causes it to glow. Fluorescent, high-intensity discharge lights (HID) and low-pressure sodium lights use this technology. HID lamps use different gases to produce light:

Mercury Vapor Metal Halide High Pressure Sodium

Metal Halide Fluorescent Tube Compact Fluorescent Light

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These types of lights require a ballast, which is a device that starts the lamp and regulates its operation.

Incandescent:

An incandescent bulb consists of a filament that glows when electricity is passed through it.

Incandescent Bulb

A halogen lamp is a type of incandescent lamp where high-pressure halogen gas is inside the bulb allowing the filament to burn hotter and longer.

Halogen Lamp

OTHER LIGHT SOURCES

Direct chemical

Chemoluminescence (lightsticks)

Fluorescence

Phosphorescence

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Terrestrial

Bioluminescence

Luciferase - found

in glowworms (Arachnocampa and Phengodidae), fireflies (Lampyridae), and

certain bacteria

Aequorea victoria (a type of jellyfish)

Antarctic krill

Parchment worm (Chaetopterus), which exhibits blue bioluminescence despite having no

light sensitivity

Cavitation bubbles

The common piddock (Pholas dactylus)

Foxfire, one of up to 71 known species of luminescent fungus

Glow worm

Sonoluminescence

Celestial and atmospheric light

Astronomical objects

Sun (sunlight, solar radiation)

Sunset & sunrise

Diffuse sky radiation

Corona

Photosphere

Starlight (Stars forming groups such as star clusters and galaxies and indirectly lighting nebulae)

Bright star (list)

Deep sky objects including quasars, accretion discs around black holes, blazars, magnetars,

misc. nebulae, pulsars

Supernova / nova / hypernova

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Milky Way

Atmospheric entry (via ionization and/or heating; can be man-made, also)

Meteors

Meteor showers (articles, list)

Bolide

Earth-grazing fireball

Lightning (Plasma (physics))

Sprite (lightning)

Ball lightning

Upper-atmospheric lightning

Dry lightning

Aurorae

Čerenkov radiation (from cosmic rays hitting atmosphere)

Combustion

Fire

Acetylene/Carbide

Argand

Candle

Diya

Gas

Kerosene

Lantern

Limelight

Oil

Rushlight

Torch

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Types of Lighting FixturesWhether you choose a valance or pendant, there's a fixture for every need in your home

By Jill Connors

Many options exist for providing light in a home, from integrated architectural solutions that

require contractors and tradesmen, to decorative lamps that need only be placed on a table and

plugged in to the nearest outlet. Although some types of fixtures are more commonly associated

with a particular layer of lighting—ambient, task or accent—most fixtures are versatile enough to

be used in a number of ways.

Architectural. The three most common forms of architectural lighting are cove, soffit and

valance; all three are integrated into the room's structure. Cove lighting is located in a ledge,

shelf or recess high up on a wall, and the light is bounced toward the ceiling or upper wall. Soffit

lighting is located in a soffit or cornice near the ceiling, and the light radiates downward,

washing the wall with light. Valance lighting is located in a wood, metal or glass valance

(horizontal shield) mounted above a window or high on the wall, and the light bounces both

upward and downward. The technique of bouncing light off walls and ceilings is known as

indirect lighting, which is favored by many lighting professionals because indirect lighting

minimizes shadows and glare. Architectural lighting is most often used as ambient lighting.

Recessed. Installed above the ceiling, this type of lighting has an opening that is flush with the

ceiling. A recessed light requires at least 6 inches of clearance above the ceiling, and insulation

is essential to ensure that condensation does not drip into the fixture. Recessed lighting sends a

relatively narrow band of light in one direction; it can be used to provide ambient, task or accent

lighting.

Track. Mounted or suspended from the ceiling, track lighting consists of a linear housing

containing several heads that can be positioned anywhere along a track; the direction of the

heads is adjustable also. Track lighting is often used for task or accent lighting.

Undercabinet. Mounted under kitchen cabinets, this type of lighting can be linear or a single

puck-shaped fixture. Undercabinet lighting is extremely popular as task lighting in a kitchen.

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Pendants. Suspended from the ceiling, a pendant light directs its light down, typically over a

table or kitchen island. A pendant can enhance the decorative style of a room. Pendants can

provide ambient or task lighting.

Chandeliers. Suspended from the ceiling, chandeliers direct their light upward, typically over a

table. They can enhance the decorative style of a room. Chandeliers provide ambient lighting.

Ceiling. This type of fixture is mounted directly to the ceiling and has a glass or plastic shade

concealing the light bulb. Ceiling fixtures have been common in homes for nearly a hundred

years, often providing all the ambient light in a room.

Wall Sconces. Surface-mounted to the wall, sconces can direct light upwards or downwards,

and their covers or shades can add a stylistic touch to a room. Wall sconces provide ambient or

task lighting.

Desk, Floor & Table Lamps. Made in a wide range of sizes and styles, lamps are extremely

versatile and portable sources of light in a room. Most lamps direct light downward, with the

exception of a torchiere, which is a floor lamp that directs its light upward. Lamps are often used

as task lights, particularly for reading, but can also provide ambient light.

Luminaires or Lighting Fixtures

is the device which supports thesource or sources of electric light and redirects or helps to control the light rays from the source. Control ofthe rays is necessary to secure evendistribution, to avoid glare, to cut-offdirect rays to the eyes, andeliminates disturbing reflection of the rays from polished surfaces.

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Ceiling mounted downlights

SPOTLIGHTS

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PENDANTS

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WALL LIGHTS

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FLOOR LIGHTS

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EXTERIOR LIGHTS

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ODDITIES

TASK AND TABLE

LIGHTS

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LIGHTING SYSTEMS

1. Cornice Lighting

A system where light sources are shielded by a panel parallel to the wall and attached to the ceiling to distribute light downwards over the wall. This is considered as direct lighting.

2. Cove Lighting

A system where light sources are shielded by a ledge to distribute light upwards over the ceiling and upper wall. It is a form of indirect lighting.

3. Valance Lighting

A system where light sources are shielded by a panel parallel to the wall usually across the top of a window. This provides light both upwards and downwards over the wall.

QUALITY OF LIGHTLight Distribution depends upon:

Uniformity

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freedom from variations of illumination in a room or space. Absolute uniformity signifies same intensity throughout and it is not always practicable to attain. A deviation of 25% from the average intensity cannot be detected by the eye, and is considered an acceptable maximum.

Diffusion

refers to the number of directions and angles from which illuminating rays proceed. Good diffusion is obtained when light falls upon a matte or satin surface from a variety of directions thus eliminating shadows and streaks of brilliancy. Poor diffusion results from illumination from one direction only thus causing visual confusion because of distorted highlights and shadows

Absence of Glare

Glare is defined as the effect of brightness in the field of vision which causes annoyance or discomfort, or in worse cases, interferes with seeing. When the glare is caused by light sources in the field of vision, it is known as “direct glare” or “disability glare”. When glare is caused by the reflection of a light source in a viewed surface, it is known as “reflected glare” or “discomfort glare”.

Bare lamps or brilliant fixture globes should never be in the line of sight from any point in the room. An angle of 45 deg. between the horizontal and the line of sight (line from the lamp to the eye) is generally accepted as the greatest permissible angle.

Color of Light

depends upon the type of lamp chosen. Incandescent lamps provide yellow light; although there are many other colors depending upon the color of their glass bulbs. Fluorescent lamps have the greatest variety of colors ranging from daylight to bluish white and even pinkish white. Color is also used to enhance certain qualities. For example, de luxe FL lamps are used to enhance food in restaurants

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