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Designing and Specifying Display Systems
Copyright 2012 by InfoComm International®
Visual Principles Objectives
• This seminar covers five key points:
– Determining an acceptable contrast ratio
– Determining acceptable ambient light level on projection
screen
– Establishing actual projector brightness
– Selecting projector and lens
– Balancing task lighting

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Copyright 2012 by InfoComm International®
System Contrast Ratio
• The light that is perceived at our eyes
• Includes
– Projector
– Screen material
– Ambient light
– Viewing task
Copyright 2012 by InfoComm International®
Candle Power

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Copyright 2012 by InfoComm International®
Illuminance And Luminance
• Illuminance
• Light that is falling on a
surface
• Ex: light falling on a table
• Luminance
• Light coming from or
transmitted through a
surface
• Ex: light entering a camera
Copyright 2012 by InfoComm International®
ANSI Lumen Calculation
• Meter aimed at lens
• Meter readings in “lux”
• Average of 9 zones
• Screen dimensions in meters
• Avg. lux * meters ² of screen = ANSI lumens

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Copyright 2012 by InfoComm International®
Copyright 2012 by InfoComm International®
System Black
• Display systems create light, they do not create dark.
• The screen’s ability to reproduce black is limited to the darkness
of the screen when it is turned off
• 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.

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Copyright 2012 by InfoComm International®
• System Black
Copyright 2012 by InfoComm International®
Contrast Ratio
• Measures the
brightness
compared with the
ability to represent
black
simultaneously
• Measured by
average readings
of 8 black and
white zones each
• High contrast
images:
– appear crisper
– appear to have more
depth.
– easier to read text

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Copyright 2012 by InfoComm International®
System Contrast Ratio
• The light that our eyes receive
• Includes the entire light path
– Projector
– Screen
– Ambient light
Copyright 2012 by InfoComm International®

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Copyright 2012 by InfoComm International®
ANSI/INFOCOMM 3M-2011
• Projected Image System Contrast Ratio
• 5 viewing positions
• 4 viewing tasks
Copyright 2012 by InfoComm International®
Five Viewing Positions
Closest LeftClosest Left
Closest RightClosest Right
CenterCenter
Farthest LeftFarthest Left
Farthest RightFarthest Right

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Copyright 2012 by InfoComm International®
Four Viewing Tasks
• Passive Viewing minimum 7:1
• Basic Decision Making minimum 15:1
• Analytical Decision Making minimum 50:1
• Full Motion Video minimum 80:1
Copyright 2012 by InfoComm International®
Conformance
• CONFORMS: All five measurement (viewing) locations
meet or exceed
• PARTIALLY CONFORMS: One but no more than four
measurement (viewing) locations falls below by less
than 10%
• FAILS TO CONFORM: The contrast ratio at any one of
the measured locations falls below 10%

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Copyright 2012 by InfoComm International®
Calibrating With The Grey Scale Pattern
Copyright 2012 by InfoComm International®
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Copyright 2012 by InfoComm International®
Calculate Projector Brightness
Pbrightness = ((ambient light * 15 * screen area) / screen gain) / (1
– 0.XX derating)
= ((55 lux ambient light reading * 15 * 92 in x 57.5 in screen) / 1
Gain) / (1-25% derating)
Convert sq feet to meters for lumens result ( * 0.0929)
= 3743.4 lumens
Round up lumens to next commercially available projector
Copyright 2012 by InfoComm International®
What difference can a lens make?
Lens aperture and f-stops
Lens focal length = f-stop
Lens diameter
These represent full f-stops (1/2 or 2x light):
1.0 1.4 2.0 2.8 4 5.6 8 11 16 22
Brighter

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Copyright 2012 by InfoComm International®
Task Light Levels
• ±3x range
between display
brightness and
task lighting levels
Copyright 2012 by InfoComm International®
• This seminar covered five key points:
– Determining an acceptable contrast ratio
– Determining acceptable ambient light level on projection
screen
– Establishing actual projector brightness
– Selecting projector and lens
– Balancing task lighting

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Copyright 2012 by InfoComm International®