Illumination II Video, Poll and Canvas Quiz Questions

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

T/F: 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

T/F: 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

T/F: 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

T/F: 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

T/F: 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

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

Footcandles and lux are both units of illuminance. Which of the following best describes the quantity expressed by footcandles?

lumens per square foot

The lumen is defined based on ______________ also known as ______________ curve.

V (lambda); photopic

The property of radiant power waves that most closely corresponds to our perception of color is

Wavelength

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.

less

The candela (or candlepower) is the unit used for luminous intensity. Luminous intensity is a density that is best described by which of the following expressions?

lumens per steradian

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

T/F: 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

T/F: 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

T/F: Research shows that we have a preference for red saturation. The more saturated the color the more we like it.

False

T/F: 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

T/F: The SPD curve for a light source describes the potential for providing the appropriate density of light; SPD means Source Potential Distribution

False

T/F: The cornea provides adjustable focusing power, while the lens provides most of the focusing power.

False

T/F: 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

T/F: 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

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

T/F: 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

T/F: 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

T/F: 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

T/F: Cones are wired to various ganglion cells; the same cones send information from more than one receptive field, and these fields can overlap.

True

T/F: 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

T/F: 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

T/F: Our visual system can only see a portion of optical radiation.

True

T/F: 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

T/F: The third parameter of a three-dimensional color space is luminance

True

T/F: 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

T/F: The types of photoreceptors are rods, cones and ipRGCs

True

T/F: 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

T/F: The visible spectrum is bounded by ultraviolet (UV) radiation on one side and in infrared (IR) radiation on the other

True

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 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 IES is the body in the lighting industry that sets the standards for lighting practice. IES stands for:

Illuminating Engineering Society

A two-dimensional color space maps perceptions of light produced by a combination of primary colored lights ( ___________) in different _____________.

R, G, B; amounts

When you are in very dark room, which photoreceptors are helping you see?

Rods

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 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

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

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

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