A-C

Terminology

Definition
Acoustic Transparence
 The ability for sound to penetrate a material (in this case, a projector screen) with an acceptably low level of  attenuation.
ALR
 Acronym for Ambient Light Rejecting
Ambient Light
 Any atmospheric light from sources other than the projector and its screen image.
Ambient Light Rejecting
 A specialty projection screen material filters out ambient light from the projected imagery.  This material does so by either absorbing incident light signals or redirecting it away from the viewer’s field of vision.
Angular Reflective
 A type of High Gain and/or ALR  screen material that reflects projected light at a mirror opposite angle to that of the angle of incidence.
Angular Serriform Microstructure
 Microscopic “saw-tooth” reflective structures that are angled for use as a Ceiling Light Rejecting projector screen. (Also see “Serriform Microstructure”)
ANSI
 Acronym for American National Standards Institute.
ANSI Lumens
 An SI derived unit of luminous flux equal to the light emitted in a unit solid angle by a uniform point source of one candle intensity. Or (1 candela * sr) Symbol = lm as established by the ANSI.
Aspect Ratio
 The actual shape of a projection screen determined by a set of  corresponding width to height measured in equal units.  In other words, a screen that measures 4 units of width by 3 equal units of corresponding height, has a 4:3 aspect ratio. Or if there are 16 unts of width to every 9 units of height, the aspect ratio is 16:9.
AT
 Acronym for “Acoustically Transparent”
Backlighting
 Any light originating from an ambient light source behind the projector screen.  This includes LED light kits attached to the backside of a screen’s framework or even projected light penetrating a thin screen material and reflecting off the wall, visibly  illuminating that which is  behind the screen material.
Bandwidth
 The range of frequency measured in a particular device’s transmission capability.  An example is how video is expressed in MHz (or measure of frequency cyles in the thousands per second.)
Ceiling Light Rejecting
 A specialized material’s ability to reject the washout effects of overhead lighting.
CLR
 Acronym for Ceiling Light Rejecting
Color Gamut
 The full RGB color range that a particular device (like a projector) is capable of.
Color Resolution
 The number of colors available from a device that is measured in bits per pixel.
Color Saturation
 Is the measurement of the various levels of intensity in image color.  The higher the saturation, the more vivid a particular color is.  The lower the color  level, the more gray the image becomes. (see grayscale)
Color Temperature
 Color temperature is a feature of  visible light measurement used in various “light-related” industries from  lighting and photography, to video and all light-related sciences.  It is measured in Kelvin (K) temperature units.  “Cool colors” blues-whites are measured above 5000 K.  Lower temperature measurements of 2700-300 K produce “warm colors” ranging from yellows to reds.
Contrast Ratio
 Contrast is the perceptible differences of color luminescence that allows the human eye to determine patterns and textures in a visible image.  Dynamic Range plays a role in this process by intermingling with color saturation enabling individuals to perceive a myriad of different color shades.
Certified Technology Specialist
 A process hosted by InfoComm International that certifies Audio-Visual technology specialists based on the exacting requirements of posessing intricate knowledge of the AV industry.
CTS
 Acronym for Certified Technology Specialist

Terminology

Definition
Diagonal Size
 The diagonal measurement of a projection screen. This measurement typifies individual product names (eg. 100″ Screen, 150″ Screen, &etc.)
Diffusion Uniformity
 This is also typically described as “viewing angle” whereas the brightness is equal over a given range .  The most common application is “wide diffusion uniformity” meaning that there is equal brightness over the full 180° from which the image can be seen.
DLP “Digital Light Processing”
 Acronym for Digital Light Processing – a technology developed by Texas Instruments that uses hundreds of thousands of microscopic spinning mirrors for image reflection and is considered by many to be the best technology for accurate color reproduction.
Edge Blending
 The process of synchronizing multiple projectors to link their individual projected images to form one seamless, continuous picture.
Flat Panel Display
 The most common (non projector) video display used as television/video displays, computer monitors, etc. Typically they use an LCD and/or LED technology Ride profile is less than 10cm and are either a *Often erroneously confused with Flat Panel (CRT) Television Sets.
Flat Screen
 Typical name for a CRT that achieves a flatter side profile by using multiple electron guns as opposed to a single electron gun as was used in antique TV sets. Also used interchangeably with “Flat Panel Display”.
Focal Length
 Distance between the lens and focal point (center of projection).
Format
 Commonly used to describe either the screen’s aspect ratio or the actual model type (eg. Manual, electric, portable, fixed-frame, etc.)
Front Projection
 The projection layout where the projector is set up in front of the projection screen’s front (viewing surface).  This is the most common projection array.
Front Room Position
 Typically refers to placing a short throw projector within a distance that equals 75% to 120% of the screen/image’s actual size (diagonal measurement).

Terminology

Definition
Gain
 Unit of measure depicting a projection screen’s actual brightness.  The industry standard testing control measuring at pure “white” is magnesium carbonate at 1.0 gain.  Gain measurements less than 1.0 are called “sub gain” while measurements over are called “high gain”.
Grayscale
 The level of gray that becomes more apparent as the color saturation decreases.  With 0% color saturation, the only visible shades are the dynamic range between “white” full neutral light) and black (the lack of light).
HDTV
 Acronym for “High Definition TeleVision” the most common broadcast television aspect ratio measuring 16:9 or 1.78:1. (see aspect ratio)
Herz (Hz)
 Measure of frequency in cycles per second. This is the standard measurement in audio, visual, and electrical signals.
High Gain
 A material that measures with a brightness that is 1.1 gain or higher. (see gain)
Horizontal Resolution
 The full number of vertical lines individually crossing the horizontal rows of a projected image. This is measured in pixels and is often used in defining aspect ratios such as in HDTV, 1920 × 1080 indicates the ratio of 1920 pixels of horizontal resolution to 1080 pixels of vertical resolution.
Hz
 Measure of frequency in cycles per second. This is the standard measurement in audio, visual, and electrical signals.
Invert Image
 Projector setting that allows the image to invert should the projector be ceiling-installed.
ISF
 Acronym for Imaging Science Foundation.  A world renowned organization that measures and identifies the ranges and optimal settings of Dynamic Range, Color Saturation, Color Accuracy, and Resolution.

Terminology

Definition
Keystone Correction
 A projector’s ability to correct the distortion caused when a projector is vertically off-axis from the screen.  Instead of seeing an image that is wider or narrower at the top of the image than at the bottom, Keystone eliminator corrects the artifact by restoring the image to a proportionate rectangle where the bottom width is equal to that of the top.
Keystone Eliminator
 A feature typically found on portable projector screens that allows the surface to be physically tilted to correct keystoning.
Keystoning
 A projector artifact caused when a projector is vertically off-axis from the screen.  Instead of seeing a proportionate rectangle-shaped image, the top or the screen is either wider r narrower than the bottom.
LCD
 Acronym for Liquid Crystal Display. It is used in high-resolution projected imagery and is the alternate to DLP technology.
Lenticular
 A front or rear projection screen that utilizes a textured optical surface that adequately diffuses on or off axis light signals.
Long Throw Lens
 Specialty lens designed to allow a projector to throw a smaller sized image from a greater distance.  An example would be in commercial theaters.
Low Gain
 The measured screen brightness or “gain” is less than 1.0.  Also referred to as “negative gain”.
Lumens
 Measurement of SI derived unit of measurement for luminous flux.  It is used to measure the brightness of a projector’s output.

Terminology

Definition
Metal Halide Lamp
 Type of projector lamp that operates at a very high temperature to produce superior white and blue levels over that of Halogen lamps. Used in higher end portable projectors.
Moire
 Visual artifact commonly caused when the projector’s pixel resolution is incompatible with the openings on an accoustically transparent material.  It causes a “cross-hatched” or “rippled” pattern in the projected content.
Negative Gain
 The measured screen brightness or “gain” is less than 1.0. Common in ambient light rejecting (ALR) projector screens.
NTSC
 Acronym for National Television System Committee.  It is the USAA broadcast standard, also referred to as 4:3 aspect ratio and has been mostly superseded by HDTV (16:9)
OHP
 Acronym for Overhead Projector.  It is a squared (1:1) aspect ratio.
Overhead Projector
 It is a squared (1:1) aspect ratio transparent projector.

Terminology

Definition
Pixel
 The smallest component of a displayed image. It is essentially the “dots” that make up a digital image and each is composed of a red, blue, and green subpixel.  Pixels are used in defining aspect ratios such as in HDTV, 1920 × 1080 indicates the ratio of 1920 pixels of horizontal resolution to 1080 pixels of vertical resolution.
Pluge
 Acronym for Picture Lune Up Generation Equipment.  It is a test pattern used to calibrate dynamic range (aka. Black levels)
Power Zoom
 Motorized zoom adjustor on a projector that allows the end-user to adjust by means of a remote control.
Projection Axis
 The invisible line of alignment that runs from the center of the projection lens through the center of the projector screen.
PVC
 Polyvinyl chloride. Synthetic material used in the manufacture of many tab-tensioned and fixed frame projection screen materials.
Real Time
 When the transfer time of data between the media player and the projector-to-screen is visually imperceptable. This is ideal for using projectors with gaming systems. When the transfer time is apparent, it is known as “Lag Time” and is measureable in fractions of a second.
Rear Projection
 Projector material designed for a projected image to penetrate from behind a screen in the direction of the viewers facing the screen’s front.
Retro Reflective
 When projected light reflects off the screen material at the mirror opposite direction to the angle of incidence.
RGB
 Acronym for Red/Green/Blue colors that when used in the right combinations will create the full color range in electronic video devices.
RJ45
 8-position 8-contact modular port & plug. Common computer and ethernet connection.
RS232
 Standard Telecommunications serial port that connects data terminal equipment (DTE) such as computers and modems.

Terminology

Definition
Serriform Microstructure
 A series of microscopic reflective structures in certain types of ALR projector screens that has a cross-section resembling a “Saw-toothed” appearance when viewed through a microscope.
SMPTE
 Acronym to the Society of Motion Picture and Television Engineers.
Throw Distance
 The distance between the projector’s lens and the actual projection surface.
UXGA
 Acronym for Ultra Extended Graphics Array. A finer-detailed variant of the XGA 16:10 aspect ratio measuring 1600 x 1200 pixels
Ultra Short-Throw Projectors They are designed to be positioned flush with the screen and still create a huge image. Pull it back a few inches and the picture nearly doubles in size. These typically have a reflector lens to spread out its light signal over a minimal distance. About 3-20 inches (8-50cm) Shop Elite Projector
Vertical Resolution
 The full number of horizontal lines individually crossing the vertical rows of a projected image. This is measured in pixels and is often used in defining aspect ratios such as in HDTV, 1920 × 1080 indicates the ratio of 1920 pixels of horizontal resolution to 1080 pixels of vertical resolution.
VGA
 Acronym for Video Graphics Array
VGA Resolution
 Video Graphics Array. 640 x 480 resolution pixel display (4:3)
Video Compatibility
 Ability for media players, computers and projectors to transmit and receive data through various  standards such as VHS, NTSC, and PAL

Terminology

Definition
Wide Diffusion Uniformity
 The ability for a screen to diffuse a projected signal into an image of equal brightness regardless of how off-axis the viewer’s perspective is.
XGA
 Extended Graphics Array. 16:10 aspect ratio with 1024 x 768 pixel resolution.
Zoom Lens
 A lens that has an adjustable focal length to allow proper image clarity to be achieved without physically moving the projector closer to or further from the screen.