BU 001. ENGINEERING UTILITIES
MODULE 3. ILLUMINATION
Light as a Creative Medium
Light is a creative medium, the most powerful of all. Most of what we know of our world comes
to us through our eyes, and we have learned that way we see things depends on how they are lighted.
Light in Design - Bringing the Vision to Life
This application guide shows how lighting makes a difference - a practical and creative guide
to the process of designing with light. It concentrates on the three essential choices:
1. What to light
2. How to light it
3. What to light it with
What to Light
Deciding what to light can often best be approached as layered composition in which the nature
of objects and surfaces being lighted play an important role.
What we actually see is almost always the reflection of light from a surface, not light itself.
Hence, we must consider the surface characteristics.
-
Is it light or dark?
-
Is it polished or mirror-like?
-
Is it finely or coarsely textured?
-
Is the color one we would like to enhance or one we would like to subdue?
I.
DEFINITION OF TERMS
❏
Luminous Intensity
Dark objects absorb more light, reflects less.
Polished surfaces will reflect images.
Textured surfaces will diffuse the light striking them.
The color of the object is determined by the color qualities of the source.
The luminous flux emitted per unit solid angle by a light source, expressed in
candelas.
❏
Candela
The basic SI unit of luminous intensity, equal to the luminous intensity of a source that
emits monochromatic radiation of frequency 540 x 1012 hertz and that has a radiant
intensity of 1/683 watt per steradian. Also called Standard Candle.
❏
Candlepower
Luminous intensity expressed in candelas
❏
Candle
A unit of luminous intensity used prior to 1948, equal to the luminous intensity
wax candle of standard specifications.
of
a
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❏
Luminous Flux
The rate of flow of visible light per unit time, expressed in lumens.
❏
Lumen
The SI unit of luminous flux, equal to the light emitted in a solid angle of one steradian
by a uniform point source having an intensity of one candela.
❏
Inverse Square Law
One of several laws relating two quantities such that one quantity varies inversely as the
square of the other, as the law that the illumination produced on a surface by a point source
varies inversely as the square of the distance of the surface from the source.
❏
Illumination
The intensity of light falling at any given place on a lighted surface, equal to the luminous
flux incident per unit area and expressed in lumens per unit of area. Also called Illuminance.
❏
Lux
The SI unit of illumination, equal to one lumen per square meter.
❏
Foot-candle
A unit of illumination on a surface that is everywhere one foot from a uniform point source
of one candela and equal to one lumen incident per square foot.
❏
Luminance
The quantitative measure of brightness of a light source or an illuminated surface, equal
to the luminous intensity per unit projected area of the source or surface viewed from a
given direction.
❏
Lambert
A unit of luminance or brightness equal to 0.32 candela per square centimeter.
❏
Foot-lambert
A unit of luminance or brightness equal to 0.32 candela per square foot.
❏
Brightness
The sensation by which an observer is able to distinguish between differences in luminance.
❏
Solid Angle
An angle formed by three or more planes intersecting at a common point.
❏
Steradian
A solid angle at the center of a sphere subtending an area on the surface equal to the square
of the radius of the sphere.
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Incidence
The striking of a ray of light or sound wave on a surface.
Angle of Incidence
The angle that a straight line, such as a ray of light falling on a surface, makes with a normal
to the surface at the point of incidence
1.
Reflection
The return of light, sound, or radiant heat after striking a surface.
❏
Angle of Reflection
The angle that a reflected ray makes with a normal to a reflecting surface at the
point of incidence.
❏
Law of Reflection
The principle that when light or sound is reflected from a smooth surface, the angle of
incidence is equal to the angle of reflection, and the incident ray, the
reflected ray,
and the normal to the surface all lie in the same plane
❏
Specular
Directed from a smooth, polished surface.
❏
Reflectance
The ratio of the radiation reflected by a surface to the total incident on the
surface.
❏
Alberto
The ratio of light or radiation reflected by a surface to that incident upon it,
measured on a scale from zero for no reflecting power of a perfectly black surface
to 1 for the perfect reflection of a white surface.
2.
Refraction
The change of direction of a ray of light as it passes obliquely from one medium
another in which its velocity is different
❏
into
Angle of Refraction
The angle that a refracted ray makes with a normal to the interface between two
media at the point of incidence.
3.
Diffusion
A scattered reflection of light from an irregular surface or an erratic dispersion
through a translucent material.
❏
Diffuse
Dispersed from an irregular surface.
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4.
Diffraction
The modulation of light or sound waves as they bend around the edges of an obstacle
in their path.
5.
Absorptance
The ratio of the radiation absorbed by a surface to the total incident on the surface.
Transmittance
The ratio of the radiation transmitted through and emerging from a body to the
total incident on it, equivalent to one minus the absorptance.
Opaque
Impenetrable to light
Translucent
Transmitting and diffusing light so that bodies on the opposite side are not clearly visible.
Transparent
Capable of transmitting light so that bodies situated beyond or behind can be distinctly seen.
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II. LIGHTING
The science, theory, or method of providing illumination through the use of electric lamps.
Basic Types of Lighting
A.
According to Illumination
1.
General Lighting
2.
Accent Lighting
3.
❏
Task Lighting
General Lighting
Lighting designed to provide a uniform level of illumination throughout an area. Also called
the Ambient Lighting.
Examples:
1.
Chandeliers
Probably the oldest form of general lighting fixtures, chandeliers originally used with
candles. Chandelier fixtures are your go-to solution if you want a classic look on your
house, and are better applied to high ceilings.
2.
Pendants
In many ways, pendants are quite similar to chandelier fixtures. We can even arguably say
that pendants are the modern equivalent to chandeliers with very few exceptions.
3.
Track Light
A fairly new and modern type of general lighting. Very versatile and can be used with almost
all kinds of ceilings.
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❏
Accent Lighting
Lighting that calls attention to a particular object or feature in the visual field, or
that forms a decorative pattern on a surface.
Examples:
1.
Wall Lights
One benefit of using wall fixtures are the size flexibility, only limited by the wall space.
Great for lighting paintings or even wall architecture.
2.
Recessed Lighting
Recessed lighting fixtures are those holes, most commonly found in ceilings, that house
an illumination source. Unlike chandeliers, pendants or flush mount lamps, which are designed
to be visible, recessed lamps provide light without a visible fixture.
3.
Landscape Lighting
The use of outdoor illumination of private gardens and public landscapes; for the enhancement
and purposes of safety, nighttime aesthetics, accessibility, security, recreation and sports,
and social and event uses.
❏
Task Lighting
Lighting designed to provide strong illumination for a visually demanding activity,
such as reading or sewing.
Examples:
1.
Floor Lamps
The most common form of task lighting.
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2.
Desk Lamp
A desk lamp is a portable task light that sits on a desk or table to provide targeted
illumination for accomplishing tasks.
3.
Swing Arm Lamps
Functional swing arm lamps, like the one shown below, feature an adjustable arm that pivots
and swings into a number of positions, allowing you to control the position of the lighting
source. This makes them ideal for reading or other tasks.
4.
Under Cabinet Lights
Under cabinet lighting refers to light fixtures that are installed most commonly underneath
upper wall kitchen cabinets, illuminating the space directly below.
5. Vanity Lights
Vanity lighting is any light installed over your bathroom sink.
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B.
According to Direction
1.
2.
3.
4.
5.
6.
Direct Lighting
Lighting in which luminaires distribute 90% to 100% of the emitted light downward on
the surface or area to be illuminated.
Semi-Direct Lighting
Lighting in which luminaires distribute 60% to 90% of the emitted light downward.
Indirect Lighting
Lighting in which luminaires distribute 90% to 100% of the emitted light upward, esp.
to avoid glare or prevent shadows.
Semi-Indirect lighting
Lighting in which luminaires distribute 60% to 90% of the emitted light upward.
General Diffuse Lighting
Lighting from luminaires that emit an approximately equal distribution of light upward
and downward.
Direct-Indirect Lighting
General diffuse lighting in which little light is emitted in the horizontal plane of
the luminaires.
C.
According to Uses
1.
Highlight
2.
Backlight
3.
4.
5.
To emphasize by illuminating with a strong light.
To illuminate something from behind in order to enhance depth or to separate the subject
from its background.
Sidelight
Light coming or produced from the side.
Soft Light
Diffuse light that produces little contrast and poorly defined shadows on the subject.
Hard Light
Direct light that produces high contrast and distinct shadows on the subject.
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III.
LAMP
Any of various devices for producing light or heat, as by electricity or gas.
Types of Lamps
1.
Incandescent Lamp
3.
Discharge Lamp
5.
Neon Lamp
2.
4.
1.
Fluorescent Lamp
Light Emitting Diode ( LED )
INCANDESCENT LAMP
A lamp in which a filament gives off light when heated to incandescence by an electric current.
Also called light bulb.
A. Lamp Diameter
The maximum diameter of a lamp bulb, measured in
eighths
of
an
inch.
B. Bulb
The glass housing of an incandescent lamp, filled with
gas mixture, usually of argon and
of the
an
inert
nitrogen, to retard evaporation
filament.
C. Filament
The threadlike conductor of an electric lamp that is heated to
incandescence by the passage of an electric current.
D. Maximum Overall Length
The dimension in inches from the base of a lamp to the point on the bulb farthest away,
or the base-to-base dimension of a lamp having a base at each end.
E. Light Center Length
The distance in inches from the center of the filament of a lamp and a reference plane on
the lamp base.
Lamp Base
The part of a lamp that connects to a lamp holder.
Lamp Holder
A device for mechanically supporting and making electrical contact with a lamp. Also called
lamp socket.
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2.
FLUORESCENT LAMP
A tubular discharge lamp in which light is produced by the fluorescence of phosphors coating
the inside of the tube.
❏
Fluorescence
The emission of radiation, esp. of visible light, by a substance during exposure to external
radiation.
❏
Ballast
A device for maintaining the current through a fluorescent or HID lamp at the desired
constant
value,
and
sometimes
also
providing
the
required
starting
voltage
and
current.
❏
Starter
A device used with a ballast to provide the starting voltage for a preheat fluorescent lamp.
❏
Phosphor
Any of a number of substances that emit light when excited by radiation.
❏
Triphosphor
A phosphor having peaks in three specific color regions, red, blue, and green, used to improve
the color rendering of a fluorescent lamp.
a.
b.
Preheat Lamp
A fluorescent lamp that requires a separate starter to preheat the cathodes before
opening the circuit to the starting voltage.
Rapid-Start Lamp
A fluorescent lamp designed to operate with a ballast having a low-voltage winding
than a preheat lamp.
High-Output Lamp
A rapid-start fluorescent lamp designed to operate on a current of 800 milliamperes,
resulting in a corresponding increase in luminous flux per unit
Very-High-Output Lamp
length of
lamp
A rapid-start fluorescent lamp designed to operate on a current of 150 milliamperes,
c.
providing a corresponding increase in luminous flux per unit length of lamp
Instant-Start Lamp
A fluorescent lamp designed to operate with a ballast having a high-voltage
transformer to initiate the arc directly without any preheating of the cathodes.
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Type of Fluorescent Lamp
1.
T Bulb
2.
U-bent Lamp
A tubular bulb for incandescent, fluorescent, and high-intensity-discharge lamps.
A U-shaped fluorescent lamp for square or rectangular luminaires.
3.
Circline Lamp
4.
Compact Fluorescent Lamp
A doughnut-shaped fluorescent lamp for circular luminaires.
Any of various small, improved efficiency fluorescent lamps having a single, double,
U-shaped, or spiral tube, and either an Edison screw base or an adapter for fitting an
incandescent lampholder. Compact fluore1scents emit a similar amount of visible light, use
less power, and have a longer rated life than the incandescent lamps they are designed to
replace. Abbr.: CFL
Energy Efficiency
CFLs use about 70-80% less energy compared to incandescent bulbs, making them a good choice
for reducing electricity consumption.
Lower Cost
CFLs are generally more affordable than LEDs, making them a budget-friendly option for
households and businesses transitioning from traditional lighting.
Longer Lifespan
CFLs last much longer than incandescent bulbs, though not as long as LEDs. This makes them
a practical choice for locations where lighting needs to be replaced less frequently.
Environmental Impact
While CFLs contain small amounts of mercury, they help reduce overall energy consumption,
contributing to lower carbon emissions. Proper disposal or recycling mitigates the mercury
concern.
Wide Availability
Still widely available and compatible with most existing fixtures, which makes them an easy
upgrade from incandescent lighting without major changes to installations.
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3.
DISCHARGE LAMP
A lamp in which light is produced by the discharge of electricity between electrodes in
a gas-filled glass enclosure.
High-Intensity Discharge Lamp
A discharge lamp in which a significant amount of light is produced by the discharge
of electricity through a metallic vapor in a sealed glass enclosure. Also, HID lamp.
a.
Mercury Lamp
A high-intensity discharge lamp producing light by means of an electric discharge
in mercury vapor. Also called mercury-vapor lamp.
Typically used in:
❏
Street Lighting
❏
Outdoor Sports Fields
❏
Parking Lots
Mercury vapor lamps produce bright, bluish-white light, are energy-efficient, and have a
long life, but their use has decreased due to mercury's hazardous nature and the rise of
more efficient alternatives like LEDs.
b.
Sodium Lamp
A high-intensity discharge lamp producing light by means of an electric discharge
in sodium vapor. Also called sodium-vapor lamp.
❏
Low-Pressure Sodium Lamp
A sodium lamp producing a yellow, glareless light and used esp. to illuminate roadways.
Also, LPS lamp.
❏
High-Pressure Sodium Lamp
A sodium lamp producing a broader-spectrum, golden-white light than a low-pressure sodium
lamp. Also, HPS lamp.
Typically used in:
❏
Tunnels and Underpasses
❏
Security Lighting
❏
Parks and Gardens
Sodium lamps are known for their characteristic yellow-orange light. Low-pressure sodium
(LPS) lamps are very efficient but have poor color rendering, while HPS lamps are more commonly
used for their better color output and longer lifespan.
c.
Metal Halide Lamp
A high-intensity discharge lamp similar in construction to a mercury lamp, but having an
arc tube to which various metal halides are added to produce more light and improve color
rendering.
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Typically used in:
❏
Sports Stadiums and Arenas
❏
Retail and Commercial Spaces
❏
Parking Lots and Airports
Metal halide lamps produce a bright, white light with good color rendering. They are more
energy-efficient than mercury lamps but less efficient than LEDs. They also take a few minutes
to warm up to full brightness.
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4.
LED LIGHTING
The light provided by light-emitting diode (LED) lamps in various form factors, such as
light strips, bulbs, tubes, and fixtures.
Light Emitting Diode
A semiconductor device consisting of two materials, one having a surplus of positive charge
and the other a surplus of negative charge that, when combined at a junction, releases light
energy as a forward voltage is applied. Abbr.: LED
LED Lamp
A solid-state, low-voltage electric lamp that uses light-emitting diodes (LED) as the source
of light. LED lamps offer low power consumption, long rated life, compact size, durability,
and reliability, but because of their relatively low lumen output and low color rendering
index, they must be grouped or clustered in a suitable housing to attain the equivalent
white light of CFLs and incandescent lamps. Various forms of LED lamps are available to
serve as replacements for incandescent and halogen bulbs and for fluorescent tubes.
LED Bulb
An LED lamp designed to be interchangeable with incandescent and halogen lamps in existing
luminaires, consisting of a group or cluster of high power LEDs housed in standard bulb
shapes with bases that fit normal sockets. High-power LEDs generate heat, which must be
dissipated through the use of heat sinks and cooling fins.
LED Driver
A power supply designed to deliver a constant current source for LED lamps over a range
of load voltages. Some LED drivers also offer thermal protection, DC voltage, and dimming
by means of pulse width modulation (PWM) circuits.
LED Tube
An LED lamp designed to serve as a replacement for traditional T8/T10/T12 fluorescent tubes.
LED Strip
A flexible or rigid linear module with very low profile, surface-mounted LEDs, used for
edge lighting, display lighting, and cove lighting.
LED Fixture
A fully assembled light fixture utilizing LED lamps and equipped with a compact LED driver
for connecting to 110–240 V power sources.
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Importance of LEDs:
1.
Energy Efficiency
LEDs use up to 90% less energy compared to incandescent bulbs and significantly less than
CFLs. This makes them highly efficient, helping to reduce energy consumption and lower
electricity bills, making them ideal for both residential and commercial use.
2.
Long Lifespan
LEDs have a remarkably long lifespan, often lasting up to 50,000 hours or more, compared
to around 1,000 hours for incandescent bulbs and 8,000-10,000 hours for CFLs. This reduces
the frequency of replacements, saving costs and maintenance efforts.
3.
Environmental Impact
Eco-friendly
LEDs do not contain hazardous materials like mercury, which is present in CFLs, making them
safer for both users and the environment.
Lower Carbon Footprint
Due to their high energy efficiency, LEDs contribute to a significant reduction in greenhouse
gas emissions.
4.
Durability
LEDs are more durable and robust than traditional bulbs. They are resistant to shock,
vibration, and external impacts, making them suitable for outdoor use, including harsh
environments like extreme temperatures, storms, and vibrations.
5.
Versatility and Design Flexibility
LEDs come in various shapes, sizes, and colors, offering great flexibility in design for
architectural lighting, displays, decorative lights, street lights, and even smart home
systems. They can be dimmed and used in various applications such as task lighting, accent
lighting, and general lighting.
6.
Instant Lighting
Unlike CFLs or metal halide lamps, which require a warm-up time to reach full brightness,
LEDs turn on instantly at full brightness, making them ideal for environments that need
immediate lighting, such as workspaces and streetlights.
7.
Reduced Heat Emission
LEDs produce very little heat compared to incandescent and halogen bulbs, which can waste
a significant amount of energy as heat. This makes LED lighting safer and more comfortable
for use in close proximity, such as desk lamps and interior lighting.
8.
Low Maintenance Costs
Given their long lifespan and durability, LEDs require less frequent replacement and minimal
maintenance, which is especially important for industrial, commercial, and public lighting
systems.
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9.
Improved Light Quality
LEDs offer excellent color rendering and can emit light in a variety of color temperatures
(warm to cool), which can enhance the ambiance of a space. This makes them ideal for settings
that require precise lighting, such as art galleries, retail stores, and offices.
10. Smart Lighting Capabilities
LEDs can be easily integrated into smart lighting systems, allowing for control via apps,
automation, and energy-saving features like motion sensors or daylight harvesting. This
makes them central to modern energy management systems and smart homes.
11. Global Impact
The widespread adoption of LED lighting has the potential to significantly reduce global
energy consumption, lower electricity costs, and contribute to meeting climate goals by
reducing the reliance on fossil fuels for power generation.
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IV. LIGHTING BULBS
1.
According to Shape:
❏
Arbitrary Bulb
Code:
A
The standard rounded shape for the bulbs of general-service incandescent lamps.
❏
Blunt Tip
Code:
B
A flame-shaped bulb for low-wattage, decorative incandescent lamps.
❏
Candle Tip
Code:
C
Code:
CA
A cone-shaped bulb for low-wattage, decorative incandescent lamps.
A candle-shaped bulb for low-wattage, decorative incandescent lamps.
❏
Flame Tip
Code:
F
Similar in size and shape to C Type light bulbs. However the glass bulb is blown
or etched in such a way that causes the light look as though it is flickering like a
flame.
These bulbs used in decorative applications such as chandeliers, bathrooms,
and restaurants.
❏
Globe
Code:
G
A globe-shaped bulb for incandescent lamps, having a low brightness for exposed
use.
❏
Straight Side
Code:
S
A straight-sided bulb for low-wattage, decorative incandescent lamps.
❏
Pear Shape
Code:
PS
A pear-shaped bulb for large incandescent lamps.
❏
TB Bulb
A quartz bulb for tungsten-halogen lamps, similar in shape to the A bulb but having
an angular profile.
❏
Silver Bowl
Code:
SB Bulb
An A bulb having a hemispherical, reflective silver bowl opposite the lamp base to
decrease glare.
❏
Elliptical Reflector
Code:
ER
An ellipsoidal reflector bulb for incandescent lamps, having a precisely formed internal
reflector that collects light and redirects it into a dispersed pattern at some distance
in front of the light source.
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2.
According to Reflector:
❏
❏
❏
Reflector
Code:
R
Code:
BR
Code:
PAR Bulb
Bulged Reflector
Parabolic Aluminized Reflector
A parabolic aluminized reflector bulb of cast glass for incandescent and high-intensity
discharge lamps, having a precisely formed internal reflector and a lensed front to
provide the desired beam spread.
❏
Mirror Reflector
Code:
MR Bulb
A multifaceted reflector bulb for tungstenhalogen lamps, having highly polished
reflectors arranged in discrete segments to provide the desired beam spread.
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V.
EXAMPLES OF LIGHTING FIXTURES
1.
Downlight
A luminaire consisting of a lamp set in a metal cylinder, recessed into or mounted
on a ceiling to direct a beam of light downward.
2.
Wall Washer
A downlight mounted close to the plane of a wall and equipped with a reflector,
baffle, or lens to illuminate the vertical surface.
3.
Floodlight
A lamp designed to project or diffuse a comparatively uniform level of illumination
over a large area. Also called flood, flood lamp.
4.
Spotlight
A lamp designed to project a strong, focused beam of light on an object or area.
called spot.
Also
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Spill
Superfluous
or
useless
light
rays,
as
from
a
spotlight
or
other
focused
light
source. Also called spill light.
5.
Track Light
Lighting provided by adjustable spotlights mounted along a narrow, ceiling or wall-mounted
metal track through which current is conducted.
6.
Cove Lighting
7.
Valance Lighting
Indirect lighting directed upward from an interior cornice at the edge of a ceiling.
Indirect lighting directed upward or downward from a light source concealed by a horizontal
board or band.
8.
Cornice Lighting
Indirect lighting directed downward from an interior cornice at the edge of a ceiling
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9.
Light Strip
A rigid or flexible tape with exposed low voltage light sources of 1 to 10 watts.
Also called Light Tape.
10. Troffer
A luminaire having a trough-shaped reflector holding one or more fluorescent lamps.
11. Droplight
A lighting fixture suspended from a ceiling or wall by a flexible cord, by which
can be raised or lowered.
it
12. Pendant
A lighting fixture suspended from a ceiling
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13. Bridge Lamp
A floor lamp having the light source on a hinged, horizontally adjustable arm.
14. Gooseneck Lamp
A desk lamp having a flexible shaft resembling the neck of a goose.
15. Chandelier
A decorative lighting fixture suspended from a ceiling, usually having branched supports
for a number of lamps.
16. Sconce
A decorative wall bracket for candles or other lights.
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17. Torchiere
A floor lamp having its light source within a reflecting bowl that directs the
light upward. Also, torchère, torchier.
Light Source
a.
Linear Source
A light source having one dimension significantly greater than its other dimensions,
such as a fluorescent lamp.
b.
Area Source
A light source having significant dimensions in two directions, such as a large window or
a luminous ceiling.
- nothing follows -
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