Visual Principles of Design Flashcards
The display system (also referred to as the video system) consists of _____ and _____.
the display devices themselves (flat-panel display, projector and screen, etc.) and the components that support those devices (sources, switchers, etc.).
An AV designer must consider four parameters before selecting an actual display:
- text size
- farthest viewing distance
- nearest viewing distance
- good or acceptable viewing areas.
When designing a video system, you should first consider ____.
A. Nearest Viewer Distance
B. Farthest Viewer Distance
C. Text Size
D. Viewing Area
C. Text Size
Resolution describes ____.
a video system’s ability to reproduce highly detailed information.
Visual acuity is ____.
an eye’s ability to discern fine details
Resolution Acuity is ____ .
the ability to detect that there are two stimuli, rather than one, in a visual field.
Recognition Acuity is ____.
the ability to identify correctly a visual target (i.e. the differences between a C and a G onscreen)
When determining text size, your design goal is to _____.
create a text height that is easy to read and won’t cause eye strain or fatigue.
Maximum Distance Formula
Text height × 150 = maximum distance from the screen
For the purposes of determining the farthest viewing distance for a display system, AV designers group viewing tasks into three general areas.
- Observing content - general viewing
- Inspecting content, or observing content with clues - reading with clues
- Inspecting content without clues - nspection
One way to determine a comfortable viewing experience is to base the height of the image on two criteria, _____ and _____.
- What the viewers are going to see
* Where the farthest viewer will be seated
Image Height Formula
IH/ID = DT/VT
- IH = Image height.
- ID = Distance from the farthest viewer to the image.
- DT = Viewing task ratio (height). This will always be 1.
- VT = Viewing task ratio (distance).
The image height formula reveals that tasks requiring more detail require bigger images. For the viewing task ratio, which is based on levels of detail, state the factor based on the viewing task.
- 8 - observe content (general viewing)
- 6 - inspecting content with clues (reading with clues)
- 4 - inspect content without clues (inspection)
Simple Image Height Formula Wheel
ID
______
IH | VT
- ID = Farthest viewer distance
- IH = Image height
- VT = Viewing task
if you know two of the variables, you can easily calculate the third
Farthest Viewer Distance Formula
ID = IH x TV
- ID = Farthest viewer distance
- IH = Image height
- VT = Viewing task
Image Height Formula
IH = ID / VT
- ID = Farthest viewer distance
- IH = Image height
- VT = Viewing task
Viewing Task Formula
TV = ID / IH
- ID = Farthest viewer distance
- IH = Image height
- VT = Viewing task
No less than ____ x ____ is too close to the screen.
1 x the screen width
When specifying image dimensions, the top of a screen should be no higher than __ degrees above the standard line of sight for a seated viewer in the nearest viewing position.
30 degrees
When specifying image dimensions, the middle of the screen should fall about __ degrees above the standard line of sight
15 degrees
The maximum acceptable viewing angle is __ degrees from the far edge of the screen.
A. 35
B. 40
C. 45
D. 50
C. 45
The ____ is the best place to view a screen.
good viewing area
The good viewing area is typically defined as any point within __ degrees to the left or right of the straight-on axis of the screen.
45 degrees
The total good viewing area is __ degrees.
90 degrees
The ____ for a screen falls within a 45-degree line extending outward from the left and right edges of a displayed image, rather than the center.
acceptable viewing area
In digital video systems, the term format refers to ____.
the source of the image
____ is the ratio of image width to image height.
Aspect ratio
Aspect ratio formula
width / height = ascpect ratio
Screen diagonal formula
A(squared)+ B(squared) = C(squared)
A = Heigh of screen B = Width of screen C = Diagonal of screen
Define “screen gain”.
the ability of a screen to reflect or redirect light energy in a narrower viewing area, making projected images appear brighter to viewers sitting on-axis
The higher the gain number of a screen, the ____ the viewing angle over which it provides optimal brightness.
narrower
A matte white screen diffuses light ____ along both horizontal and vertical planes
uniformly
Define “ambient light rejection”.
the ability of a screen surface to negate the effects of distracting, ambient light in a space—generally increases as screen gain increases.
Define “Contrast Ratio”.
the ratio of the luminance of the brightest color (white) to that of the darkest color (black).
With a high-gain screen, The angle of incidence (light striking the surface) is _____ the angle of reflectance (light bouncing off the surface).
A. Less than
B. Greater than
C. Equal to
C. Equal to
Matte white screens evenly disperse light __ degrees horizontally and vertically, creating a wide viewing area.
180
Matte white is a reference surface, with a screen gain of __ (also known as unity gain).
1.0
In a front projection screen, requiring extra fabric to lower the screen is referred to as ____?
extra drop
What does a masking system for a projection screen do?
allows you to change the aspect ratio of the visible area of a screen
A(n) ____ measures light coming directly from a source, such as a lightbulb, projector, or monitor.
incident meter / illuminance meter
A(n) ____ measures the light that is reflected off an object back to the meter and can vary based upon the attributes of the subject being measured.
spot meter / luminance meter
A(n) ____ is a measurement of the light quantity emitted from a constant light source across 1 square meter.
lumen
____ is an English unit of measurement expressing the intensity of light illuminating an object and describes the illumination from one candle falling on a surface of 1 square foot at a distance of 1 foot.
Footcandle (fc)
__ footcandle equals ___ lux.
1 / 10.78
___ is usually associated with metric measurements and is generally taken at a task area, which could be a video screen, note-taking location, or reading area.
Lux
Lux is a contraction of the words ____ and ____.
luminance and flux.
One lux is equal to __ lumen per square meter, or ____ footcandles.
1 / 0.093
The measurement of light reflected off a screen, the value of which depends on the intensity of the light and screen gain, is measured in ____.
candelas per meter squared (cd/m2).
Candelas measure ____.
luminance / reflected light
____ is the quantitative measure of the brightness of a light source, measured in candelas per meter squared (cd/m2)
Luminance
In video, ____is the monochromatic, or black and white, picture information
luminance (Y)
____ is light that falls on a surface, measured in footcandles (fc) or lux (lx).
Illuminance
____ is the lowest level of luminance a system is capable of producing for a task under defined operating conditions.
System black
System black is defined by three parameters.
- The material of the display screen
- The ambient light level
- The light from the display with a solid black image input
____ describes the dynamic video range of a display device as a numeric relationship between the brightest color (typically white) and the darkest color (typically black) that a system is capable of producing.
Contrast ratio
Contrast ratio formula
Contrast Ratio = Luminance average max / Luminance average min
where:
• Luminance average max = the average level of luminance of all eight white squares
• Luminance average min = the average level of luminance of all eight black squares
The ANSI/INFOCOMM 3M-2011, Projected Image System Contrast Ratio (PISCR), standard was developed to ensure high-quality images.
This standard applies to front- and rear-projection systems. It defines four acceptable contrast ratios for various use cases, based on certain criteria within a space, including ambient room light.
The following are the four contrast ratios:
- 7:1 for passive viewing
- 15:1 for basic decision making
- 50:1 for analytical decision making
- 80:1 for full-motion video (home theater)
The ANSI/INFOCOMM 3M-2011 PISCR standard calls for taking measurements in five viewing locations:
closest left and right, farthest left and right, and center.
Designers—or during actual installation, AV technicians—should measure contrast ratio using a _____ test pattern and calculate the contrast ratio at each viewing location using a spot meter.
16-position checkerboard
In the _____ viewing category, The viewer is able to recognize the images on a screen and can separate text or the main image from the background under typical lighting conditions for the viewing environ- meant.
A. Passive Viewing
B. Basic Decision Making
C. Analytical Decision Making
D. Full-Motion Video
A. Passive Viewing
In the _____ viewing category, The viewer can make basic decisions based on the displayed image. The decisions are not dependent on critical details within the image, but it allows for the assimilation and retention of information.
A. Passive Viewing
B. Basic Decision Making
C. Analytical Decision Making
D. Full-Motion Video
B. Basic Decision Making
In the _____ viewing category, the viewer can make critical decisions by analyzing details within the displayed image. The viewer is fully engaged with the details of the content, as in medical imaging, archi- tectural/engineering drawings, forensic evidence, or photographic image inspection.
A. Passive Viewing
B. Basic Decision Making
C. Analytical Decision Making
D. Full-Motion Video
C. Analytical Decision Making
In the _____ viewing category, the viewer is able to discern key elements present in a video, including details included by the cinematographer or videographer necessary to support the story line and intent. This could be in a home theater, business screening room, or broadcast postproduction suite.
A. Passive Viewing
B. Basic Decision Making
C. Analytical Decision Making
D. Full-Motion Video
D. Full-Motion Video
____ refers to the distance that a specific combination of projector and lens needs to be from the projection screen to project a specific image size.
Throw distance
Throw distance formula
Distance = Screen width * Throw ratio
- Distance is the distance from the front of the lens to the closest point on the screen.
- Screen width is the width of the projected image.
- Throw ratio is the ratio of throw distance to image width.
A ____ is the part of a displayed image that is unevenly illuminated, usually appearing as a bright area in the center.
hot spot
____ is defined as the time it takes for a lamp to reach 50 percent of its initial light output.
Lamp life
A projector should be derated by __ percent of its specified brightness.
25
The ____ indicates the amount of light that is lost as it travels through the lens.
focal ratio
The formula for required projector brightness
Lumens = L * C * A Sg / Dr
• Lumens = The required brightness of the projector in lumens.
• L = The ambient light level.
• A = The screen area.
• C = The required contrast ratio.
• Sg = The gain of the screen. Assume a screen gain of 1 unless otherwise noted.
• Dr = The projector derating value. Assume a derating value of 0.75 unless
otherwise noted.
Formula for calculating the ANSI brightness of a screen
Lumens = [(Z1+ Z2 …Z9)/9] * (SH * SW)
- Zn = One of the nine zones on a screen (lux)
- SH = Height of the image (in feet or meters)
- SW = Width of the image (in feet or meters)
the formulas for task-light levels
Task Light upper = [(Lumens / A) * Sg * Dr ] * 3
and
Task Light lower= [(Lumens / A) * SG * DR ] / 3
- Task Light upper /Ligh tlower = The task-light levels at the top and bottom of the acceptable range
- Lumens = Specified projector brightness
- A = Area of the screen
- Sg = Screen gain
- Dr = 1 minus projector derating percentage
A conference room requires videoconferencing and AV presentation capabilities. Which of the following design elements are defined by the architectural dimensions and orientation of the room? A. Display size B. Display type C. Display aspect ratio D. Display brightness
A. Display size
What is the recommended (highest) ambient lighting level illuminating a front-
projection screen within a videoconferencing space?
A. 5 footcandles (50 lux)
B. 30 footcandles (108 lux)
C. 45 footcandles (161 lux)
D. 25 footcandles (215 lux)
A. 5 footcandles (50 lux)
If a font height is 2 in (50 mm), the screen height is 60 in (1,525 mm), and
screen resolution is 1080 pixels high, what is the font size in pixels?
A. 28 point
B. 32 point
C. 36 point
D. 40 point
C. 36 point
In this case, 2/60 = X/1080. Cross multiply and divide to arrive at 36 pixels, or a 36-point font.
A matte white screen surface has a gain of \_\_\_\_\_. A. 0.5 B. 0.75 C. 1.0 D. 1.25
C. 1.0
A 16:9 screen will be installed in a lecture hall. The screen’s diagonal is 72 in (1,829 mm). What is its width? A. 50 in (1270 mm) B. 63 in (1594 mm) C. 70 in (1778 mm) D. 72 in (1829 mm)
B. 63 in (1594 mm)
If you have a projector that is 2500 ANSI lumens on a 5.5 m2(squared) standard matte white screen, what should be the limits of the task lighting? Note that the projector specification is derated by 25 percent.
A. 113.6 to 1022.7 lux
B. 120 to 175 lux
C. 515 to 1001 lux
D. 527 to 632 lux
A. 113.6 to 1022.7 lux
Task light = [(2500/5.5) * 1 * (1 – 0.25)]. For the upper limit, multiply by 3; for the lower limit, divide by 3. Your task-light range is 113.6 to 1022.7 lux.
note - do not apply squared factor to screen area
Lamp life is defined as the time it takes for a lamp to reach _____ percent of
initial output.
A. 10
B. 25
C. 50
D. 75
C. 50
You need to project an image that has a 4:3 aspect ratio. You measure the screen height and determine that it is 2,286 mm high and 3,048 mm wide. Can you use this screen for the 4:3 image?
A. Yes
B. No
C. Not enough information to determine
D. All of the above
A. Yes
You require a 16:9 screen with a height of 60 in (1,524 mm). What will the screen’s diagonal be?
A. 90 in
B. 1,524 mm
C. 3,109 mm
D. 100 in
C. 3,109 mm
In videowall design, __________ is the process of adjusting for the edges of
multiple projected images.
A. Blending
B. Pixel mapping
C. Processing
D. Orienting
A. Blending
