Lighting Exam 1
The Illuminance recommendation for offices is 30 fc. In general, since more than half of the population's age in offices is between 25 and 65, the illuminance provided should be:
30 fc
The candela (or candlepower) is the unit used for luminous intensity. Luminous intensity is adensity that is best described by which of the following expressions?
lumens per steradian
The three types of cones are labelled L, M, S, for their response to long, medium and short wavelength ranges. The response to a particular color is the result of the individual response of each of these cones.
True
The visible spectrum is bounded by ultraviolet (UV) radiation on one side and in infrared (IR) radiation on the other.
True
True or false: In the IES TM-30 system, the R(f) metric has a range of values from 0 to 100.
True
The property of radiant power waves that most closely corresponds to our perception of color is
Wavelength?
The accumulation of dirt on a luminaire directly affects this value
light loss factor
True or false: The IES Illuminance Recommendations ensure that tasks receive enough light without wasting energy to maintain task performance constant on the plateau per the relative visual performance model. Because of this, the age of the viewer is not relevant.
False
True or false: The cornea provides adjustable focusing power, while the lens provides most of the focusing power.
False
True or false: The lighting quantities of illuminance and exitance both have units of lumens per area, with area in square feet or square meters. For both illuminance and exitance, the footcandle is used as the unit when the expression is lumens per square foot.
False
True or false: The term "brightness" means the same thing as the term "luminance"
False
The 'E' in the formula above corresponds to
Illuminance
The IES is the body in the lighting industry that sets the standards for lighting practice. IES stands for:
Illuminating Engineering Society
If the light meter indicates that there are 35 fc on the desk, the equivalent in lx is?
350 lx
Color mixing with light is known as
Additive
Luminous intensity coming from a light source has units of
Candela (Candlepower or lumens per steradian)
When you are looking at a small object, at which part of the retina is the image being focused?
Fovea
Color preferences seem to be mostly affected by the saturation level of which hues?
Red
Another word for chroma is
Saturation
A lobby has a wall insert of highly polished chrome. Light reflected from this surface is an example of what type of reflection?
Specular
Per the previous question, what would happen to color space if the RGB primaries would be moved closer together?
The range of colors that could be represented would decrease
True or false: Color constancy is a mechanism by which chromatic signals are compared across most of our field of view, therefore we can extract information about the color of an object correctly in spite of the spectral composition of the source illuminating the object
True
1. Which of the following is not one of the forms of lightplay defined by Richard Kelly? a. Ambient luminescence b. Layers of light c. Focal glow d. Play of brilliants
b. Layers of light
If the E of a light source at a point is 30 fc and the source is 10 ft. away, what is the intensity of the source?
.3?
The solid wood paneling in a hotel room has a reflectance value of 0.25. The transmittance value is what?
0.0?? Or .75
True or false: According to Flynn, impressions of privacy can be reinforced by bright lighting that emphasizes central architectural surfaces.
False
True or false: According to the IES, the recommended illuminance for a kitchen counter with a critical task is 50fc. This value in lux would be 5 lx.
False
True or false: Additive color mixing means the combination of light beams with different spectral components. If I were to mix yellow and blue light I get green.
False
True or false: In the IES TM-30 system, the R(g) metric has a range of values from 0 to 100.
False
True or false: Research shows that we have a preference for red saturation. The more saturated the color the more we like it.
False
True or false: The IES Illuminance Recommendations ensure that tasks receive enough light without wasting energy to maintain task performance constant on the plateau per the relative visual performance model. Because of this, the age of the viewer is not relevant.
False
True or false: The SPD curve for a light source describes the potential for providing the appropriate density of light; SPD means Source Potential Distribution
False
True or false: The bending of light as it is transmitted through glass is know as absorptance
False
True or false: The lumen rating of a light source expresses its total output without considering the human visual system; it is a sum of the radiant power across all wavelengths.
False
True or false: The photoreceptors providing the ability to see color objects are the cones; they are plentiful in the periphery of the retina, more so than the rods which are concentrated in the fovea.
False
True or false: The photoreceptors providing the ability to see color objects are the cones; they are plentiful in the periphery of the retina, more so than the rods which are concentrated in the fovea.
False
True or false: The type of photopigment or "opsin" indicates the photoreceptor 's response to light. There are five types of "opsins", one of them being melatonin.
False
True or false: The type of photopigment or "opsin" indicates the photoreceptor's response to light. There are five types of "opsins", one of them being melatonin.
False
True or false: a light source converts radiant power (Watts in) to electric power (Watts out). The efficiency of the light source is determined by the ratio of these two.
False
According to color vision theory, a B-Y receptive field could have a blue excitatory center and a yellow inhibitory surround but not the other way around.
False (To summarize: the B-Y channel = S - (L + M); the G-R channel = M - (L + S); the Luminance channel = L + M)
True or false: light source converts radiant power (Watts in) to electric power (Watts out). The efficiency of the light source is determined by the ratio of these two.
False (electric power--->radiant power
True or false: The main difference between Exitance and Luminance is that Exitance doesn't tell us what we see.
False?
One of the IES TM-30 color rendering metrics measures how well a set of test colors under a light source match their appearance under a reference light source. This type of color metric is a measure of:
Fidelity
A campfire, a follow-spot in the theater, and an airplane seat light are all examples of
Focal Glow
For the example where source 2 has lower intensity and the same size as source 1, what statement best describes the relationship of the luminance of source 2 compared to source 1?
The luminance of source 2 is less than the luminance of source 1
For the two light sources discussed which have the same intensity and size, but different spectrum, which statement best describes the relationship between the luminances?
The luminance of source 2 is the same as the luminance of source 1
True or False: According to Flynn, impressions of spaciousness can be reinforced by uniform lighting that emphasizes perimeter architectural surfaces.
True
True or false: A metameric match tells us that two colors can be perceived as being the same, even when their spectral components are different from each other.
True
True or false: Cones and rods do not send their individual responses up the chain of information. Instead, the signals are combined into opposite color channels. This is the fundamental way color vision occurs.
True
True or false: Cones are wired to various ganglion cells; the same cones send information from more than one receptive field, and these fields can overlap.
True
True or false: If the fidelity of a source is different from that of a reference source, meaning that the Rf value for that source is less than 100, it is possible that colors rendered under it would result in higher preference and better discrimination.
True
True or false: Illuminance changes (diminishes or increases) with distance and angle of incidence.
True
True or false: Illuminance is derived from the lumen, which in turn it is based on the photopic efficiency curve V (Lambda). A multiplier is necessary to adjust for the fact that when our eyes are mesopically adapted, our eyes are more sensitive to longer wavelength.
True
True or false: In general, people prefer colors that are more saturated than they appear under the reference light source.
True
True or false: In order to account for the light not hitting a surface perpendicularly we add the cosine of the angle to the Inverse Square Law formula.
True
True or false: Our visual system can only see a portion of optical radiation.
True
True or false: The Lumen Method only works if the light in the space comes from a uniform ceiling layout
True
True or false: The formula for the Inverse Square Law is E = I / D2
True
True or false: The problem with referring to the cones as L, M, S is that by doing so we imply that the cones are most sensitive to red, green and blue wavelengths.
True
True or false: The problem with referring to the cones as L, M, S is that by doing so we imply that the cones are most sensitive to red, green and blue wavelengths.
True
True or false: The reference light source used for establishing color rendering metrics is called the blackbody radiator.
True
True or false: The third parameter of a three-dimensional color space is luminance.
True
True or false: The three types of cones are labelled L, M, S, for their response to long, medium and short wavelength ranges. The response to a particular color is the result of the individual response of each of these cones.
True
True or false: The types are photoreceptors are rods, cones and ipRGCs
True
True or false: The visible spectrum is an example of one-dimensional color space. Here, I can map the color perception of a monochromatic light such as yellow, for example; its parameter would be 580 nm. [Assume that 580 nm is an accurate number for pure yellow.]
True
The lumen is defined based on ______________ also known as ______________ curve.
V (lambda) | photopic
Definition of light:
Visually evaluated radiant energy OR spectral stimulus that produces a visual sensation via the interaction with materials
Electric power going into a light source has units of
Watts
Radiant power coming from a light source has units of
Watts
True or false: The process whereby the eye focuses incoming light on to the retina is called adaptation. The process that allows the eye to adjust to the amount of light is called accommodation.
false
Footcandles and lux are both units of illuminance. Which of the following best describes the quantity expressed by footcandles?
lumens per square foot
Lumen output of the luminaire directly affects this value A. Coefficient of utilization B. Light loss factor C. Room Cavity Ration D. None of the above
none of the above
If the amount of light arriving to the eye is high, the ________ aperture will reduce in size as the _________ relaxes and closes down,
pupil, iris
If the amount of light arriving to the eye is high, the ________ aperture will reduce in size as the _________ relaxes and closes down.
pupil, iris
The three primary colors of light are
red, green, blue
The Lumen Method allows a designer to calculate _____?
The average illuminance over an entire area.
Suppose that you wanted to produce an illuminance of 200 footcandles on a statue, from a light source that is mounted 10 ft from the statue. What value of luminous intensity do you need coming from the light source in the direction of the statue?
20000cd
The Lumen Method allows a designer to determine the ____________ level of light level over a(n) ______________. a. Initial / Rectangular area b. Maintained / Given point c. Average / Entire area
c. Average / Entire area
Which of the following is not one of the Flynn lighting modes? a. Intensity: Bright / Dim b. Color tone: Warm / Cool c. Daylight: Windows / No windows d. Distribution: Uniform / Non-uniform e. Emphasis: Central / Perimeter
c. Daylight: Windows / No windows
If the total LLF is 0.80 and the CU is 0.80. What is the new resulting E?
32 footcandles? Using numbers from previous equation: (10)(2000)(.8)(.8)/(20)(20)
The wavelength range for visible light (in nanometers) within the electromagnetic spectrum is:
380 to 700 nanometers
An office is 15 ft by 15 ft with two luminaires, each of which has lamps producing 6000 lumens. If the CU value for the luminaires is 75% for the desktops, what is the estimated average illuminance on the desktops? - 40fc. For the same luminaire used in #9 (6000 lumens output), the CU value for a 20' by 30' room is 0.80. How many luminaires would you need in this larger room to achieve an average illuminance of 64 fc?
3:8
A light source has luminous intensity of 1000 candlepower at the center of its beam, and is mounted five feet above a table. The estimated illuminance on the table directly beneath the light source is:
40 lux
An office is 15ft x 15ft with two luminaires, each of which has lamps producing 6000 lumens. If the CU value for the luminaires is 75% for the desktops, what is the estimated average illuminance on the desktops?
40fc
A 20 x 20 ft. room has 10 luminaires. Each luminaire has 1 lamp, which produces 2000 lm. What is the resulting E?
5 footcandles? (10)(2000)/(20)(20)
The IES TM-30 color rendering method uses a set of how many test colors?
99
A snowy morning, haze at twilight, and the diffuse light from the fabric structure at DIA are all examples of
Ambient Luminescence
When you are looking at a colorful object, which photoreceptors are providing the ability to see colors?
Cones
The transparent, bulged covering at the front of the eye that provides refractive power for focusing light is the
Cornea
A wall in an office space has a flat off-white paint finish. Light reflected from this surface is an example of what type of reflection? a. Specular b. Refractive c. Diffuse d. Semi-Specular
Diffuse
The formula for the Inverse Square Law is?
E=cp/d squared
An example of a _________ texture is the skin of an apple
Mircro-macro
One of the IES TM-30 color rendering metrics measures how the color saturation of a set of test colors shifts compared to their appearance under a reference light source. This type of color metric is a measure of:
Gamut
If test colors under a light source appear to be more saturated than under the reference light source, the R(g) metric is
Greater than 100
The radiant power of a light source takes form in waves that have two distinct properties:
Height of the wave and the distance between the peaks of such wave
The density of light onto a surface is defined as illuminance. Moving the light farther away from a surface causes which of the following to happen?
Illuminance decreases
What does IALD stand for?
International Association of Lighting Designers
What does CIE stand for?
International Commission of Illumination
What does ipRGCs stand for
Intrinsically photosensitive retinal ganglion cells
This calculation method is used to estimate the illuminance at a specific point & this calculation accounts for direct light only
Inverse square cosine law method
The opening in the eye that changes in size to adjust to different levels of light is the
Iris
The part of the eye that is pigmented, resulting in differences in eye color is the
Iris?
The part of the eye that provides adjustable focusing power is the
Lens
Task categories describe the level of task difficulty going from A to Y. A task labelled C will be __________ difficult than a task labelled R. (more/less/equally?)
Less
Luminous power coming from a light source has units of
Lumens
What does NCQLP stand for?
National Council on Qualifications of the Light Professions
The window in a hotel room has a reflectance of 0.25. The transmittance value is what?
Not enough information
The rod photoreceptors are primarily located in which part of the retina?
Periphery
Christmas tree lights, crystal chandeliers, and a sparkling water feature are all examples of
Play of Brilliants
A two-dimensional color space maps perceptions of light produced by a combination of primary colored lights ( ___________) in different _____________.
R, G, B | amounts
The density (amount) of light coming off of a surface is largely a function of: Matte surfaces Reflectance Diffusion Surface textures
Reflectance
The inner part of the eye that contains the photoreceptors that are responsible for sensing light is the
Retina
When you are in very dark room, which photoreceptors are helping you see?
Rods
The height and proportions of a room are used to calculate this value
Room cavity ratio
The IES TM-30 color gamut metric R(g) expresses how a light source affects which aspects of the color appearance of objects?
Saturation
The tough covering that protects the internal portions of the eye and maintains the spherical shape (but does not transmit light) is the
Sclera
My kitchen has a polished hardwood floor. Light reflected from this surface is an example of what of what type of reflection?
Semi-specular
If a signal activates both channels (R-G and B-Y) the resulting color I perceive would be:
Something other than blue, yellow, green, red
If a surface color is defined by C = r R + g G + b B, what happens to the color perception if the visual system is presented with this: 2r R + 2g G + 2b B?
The color stays the same but it's colorfulness (saturation) and lightness will increase.
The Lumen Method allows a designer to calculate _______.
The average light over an entire area
The curve that is commonly called, "V-lambda," which is best described by which of the following?
The human visual response as a function of the wavelength of light
This calculation method is used to estimate the average illuminance on a work plane & this calculation ,accounts accounts for both direct and inter-reflected light
Zonal Cavity Method
The formula above is used to find E at a point when the light hitting the surface is perpendicular. What needs to be added to the formula in order to account for the light hitting a slanted (not perpendicular) surface?
cosign?
The RGCs carry ______________ to the __________ from the _____________ . The ipRGCs are also ________________, but their information is ____________ forming.
information | visual cortex | rods and cones | photoreceptors | non-image
The RGCs carry ______________ to the __________ from the _____________ . The ipRGCs are also _______________, but their information is ____________ forming.
information | visual cortex | rods and cones | photoreceptors | non-image
The reflectance values of room surfaces directly affect this value
inverse square cosine law method
Which photoreceptors connect to the non image forming parts of the brain?
ipRGCs
