Lighting Specifications Flashcards
____ is light emitted from or reflected by an object.
Luminance
Luminance is measured in ____ or ____.
candelas per square meter (cd/m2, also referred to as a nit) or footlamberts (fL).
One nit (cd/m2) = ____ fL.
0.292
____ is light falling on a surface
Illuminance
Illuminance is measured in ____ or ____ .
lux (lx) or footcandles (fc).
One lux = ___ fc
0.09
_____ measures the direct light coming from a source, such as a lightbulb, projector, or monitor.
A. Incident Light Meter
B. Reflected Light Meter
A. Incident Light Meter
____ also known as spot meters, measure the light that bounces off an object, such as a projection screen or work surface.
A. Incident Light Meter
B. Reflected Light Meter
B. Reflected Light Meter
____ is the quantification of the color of “white” light, as rated on a numerical scale.
Color temperature
____ measures the light color that a lamp emits as a single number and indicates the “warmth” or “coolness” of the light.
Correlated color temperature (CCT)
The higher the CCT, the ____ the light. The lower the CCT, the ____ the light.
bluer / redder
The ____ measures how accurately a light source replicates a desired set of parameters. It is the effect a light source has on the perceived color of objects relative to an incandescent source of the same CCT.
color rendering index (CRI)
A lamp’s performance can be measured in lumens per watt. The number of lumens you get per watt is known as ____.
efficacy
A ____ describes the light source and light-producing components (bulb, filament, fuse, and so on).
A. lamp
B. luminaire
A. lamp
A ____ is the light source plus the structures attached to it that control and distribute light (the lamp plus sockets, housing, and so on).
A. lamp
B. luminaire
B. luminaire
Often you’ll hear ____ and luminaire used interchangeably in the AV industry.
lighting fixture
The Illuminating Engineering Society (IES) Lighting Handbook recommends task light levels in AV areas to be from ___ to ___ lux or from ___ to ___ fc.
200 to 500 / 20 to 50
AV designers should specify the amount of ambient light falling on a screen. Front-projection screen recommendation is less than ___ lux.
A. 50
B. 150
C. 200
A. 50
AV designers should specify the amount of ambient light falling on a screen. Rear-projection screen recommendation is less than ___ lux.
A. 50
B. 150
C. 200
B. 150
AV designers should specify the amount of ambient light falling on a screen. Direct display screen recommendation is less than ___ lux.
A. 50
B. 150
C. 200
C. 200
Once you’ve specified your task light levels and your ambient light limits, you can consider the types of lamps and luminaires you’ll want in the room. Lamps can be broken into three main groups.
- Incandescent
- Fluorescent
- LED
_____ work by heating a filament with electricity, which causes the tungsten wire to glow. The advantages are low initial cost and high CRI, while the disadvantages are low efficacy and high heat output.
A. Incandescent Lamps
B. Fluorescent lights
C. LED lights
A. Incandescent Lamps
_____ work by heating both an inert gas and mercury to the point of producing visible light by the phosphor coating on the bulb. The advantages are higher efficacy and cooler operation, while the disadvantages are higher initial cost and sensitivity to external temperatures.
A. Incandescent Lamps
B. Fluorescent lights
C. LED lights
B. Fluorescent lights
_____ work by converting electrical energy directly into photons through semiconductor materials. The advantages are long lamp life, high efficacy, good performance in cold weather, and longer durability. The disadvantages are high initial cost and heat sensitivity.
A. Incandescent Lamps
B. Fluorescent lights
C. LED lights
C. LED lights
The term that describes the difference in percentage between the lumen output of a lamp alone and the lumen output of the lamp within a luminaire is _____.
efficiency
____ are usually graphed as polar plots that look similar to microphone and loudspeaker plots. These graphs show the distribution of light from the vertical field and help give you a sense of the direction that light will be spread in an area of a room.
A. Candlepower distribution curves
B. Spacing criterion data
C. Lamp and ballast data
A. Candlepower distribution curves
_____ will provide you with the recommended ratio between each light’s center and the distance above the task area. This is to ensure an even distribution of light and can help you properly coordinate with your loudspeaker layout in a reflected ceiling plan or keep an even wall wash for videoconferencing lighting.
A. Candlepower distribution curves
B. Spacing criterion data
C. Lamp and ballast data
B. Spacing criterion data
_____ includes lamp type, CCT information, and CRI information.
A. Candlepower distribution curves
B. Spacing criterion data
C. Lamp and ballast data
C. Lamp and ballast data
A ____ is a grouping of luminaires (lighting fixtures) that are controlled together.
zone
It is common practice to use only __ percent of a dimmer’s capacity for incandescent loads.
80
Fluorescent loads have an inherent surge, and dimmers that control them are commonly derated by __ to __ percent.
30 to 50
A ____ is a recallable configuration of lighting levels for one or more zones.
scene or preset
Any excessive bright light that causes discomfort or a reduction in visibility is called ____, and it negatively impacts your AV design.
glare
There are two types of glare.
____ or any excessive bright light coming directly into the eyes or camera.
A. Direct glare
B. Indirect glare
A. Direct glare
There are two types of glare.
____ or any excessive bright light reflecting off a surface before coming into the eyes or camera.
A. Direct glare
B. Indirect glare
B. Indirect glare
Four layers of light are often considered in videoconference rooms, ____, _____, _____, and _____.
- Key light
- Fill light
- Back light
- Wall wash
The ____ is the brightest light on the subject.
A Key light
B. Fill light
C. Back light
D. Wall wash
A Key light
The ____ is filling in the dark spot created by the key light.
A Key light
B. Fill light
C. Back light
D. Wall wash
B. Fill light
The ____ shines on the subject’s shoulders and hair. This creates an outline around the subject and separates the subject from the wall behind.
A Key light
B. Fill light
C. Back light
D. Wall wash
C. Back light
The ____ lights the background. It helps to produce a pleasing image when using an auto-iris camera.
A Key light
B. Fill light
C. Back light
D. Wall wash
D. Wall wash
IES’s Fundamentals of Lighting for Videoconferencing recommends that fluorescent sources have a CCT of __ to __ K, with a minimum CRI of __.
3000 to 3500 K / 80
IES’s Fundamentals of Lighting for Videoconferencing recommends that halogen sources have a CCT of __ K or greater.
2800 K
