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ANSI Lumens
ANSI stands for the American National Standards Institute. ANSI is a non-profit organization that developed the standards for determining light output or brightness, measured in lumens. Lumens are the standard measurement for light output and the higher the lumen count, the brighter the projection.
Aspect Ratio
The ratio of height to width of a projection or screen. If the aspect ratio is 4:3, the width of the image is equal to 4/3 times the height. Similarly, if the aspect ratio is 16:9, the width of the image is equal to 16/9 times the height of that image.
Brightness
The visual perception of light output from an image, measured in lumens.
Contrast Ratio
Described at the ratio between white and black. The larger the contrast ratio, the greater ability of a projector to show subtle color details, present a clearer picture, and tolerate ambient room light. There are two methods for determining contrast ratio in the projection industry:
1) Full On/Off contrast measures the ratio of the light output of an all white image (full on) to the light output of an all black image (full off).
2) ANSI contrast ratio is measured using a pattern of alternating white and black rectangles. The average light output from the white rectangles is divided by the average light output of the black rectangles to determine the ratio.
In comparing contrast ratios, ensure you are comparing the same type of contrast ratio.
Data Signals
This is a listing of the data signals that can be displayed by a projector. Most projectors are compatible with Macintosh and PC computers and most projectors can display images in a higher or lower resolution. However, for the optimal performance of your projector, it is recommended that you match the resolution of the projector to that of your computer. We will typically only list the native resolution here to ensure you obtain the best picture quality possible.
Digital Light Processing (DLP)
A type of display technology developed by Texas Instruments. This technology consists of thousands of tiny mirrors that reflect light to produce images. For a more detailed explanation, please refer to our Display Definitions reference guide in the Resources section of our site.
Digital Visual Interface (DVI)
DVI is a standard that defines the digital interface between digital devices. Devices that support DVI allow for digital-to-digital connections, eliminating the conversion to analog, and delivering an undistorted image.
Display Tech
The technology used inside your projector to display images. For example, LCD or DLP. For a more indepth explanation of these technologies, please refer to our Display Definition reference guide in the Resources section of our site.
Flat Screen
Term most oftenly used when referring to a flat-panel display. A flat screen implies a traditional CRT with a flat picture tube. The items that you will find here at PresentationMart are flat-panel displays, thin display screens that utilize a number of technologies including plasma and LCD (liquid crystal display). For a more indepth explanation of these types of technologies, please refer to our Display Definition reference guide in the Resources section of our site.
High Definition Television (HDTV)
Generic term referring to a higher resolution format than previous standards. HDTV provides a wider image that more closely resembles a movie screen.
Image Size
This attribute describes the approximate image size in inches that your projector can display. This measurement is a range, depending on how far your projector is from the display area, and is measured diagonally.
Keystone Correction
"Keystoning" is caused by the projected image not being perpendicular to the screen, causing the sides of the image to distort and become different widths. A projector equipped with keystone correction can automatically correct this image distortion using a negative keystone. Most projectors have a set number of degrees to which this distortion can be corrected.
Lamp Life
This refers to the "half-life" of the lamp inside the projector. This is the point where the lamp is half as bright as it was when it was first being used. It will gradually lose brightness with use, and it is recommended to replace your lamp when it exceeds it's lamp life.
Lens Shift
Most projectors are equipped with lens shift to allow for the optical lens to be physically shifted up and down (vertical) or left and right (horizontal). Vertical len shifting is the most popular type of shift because it allows for keystone correction and assist in aligning images when multiple projectors are used stacked on top of one another.
Liquid Crystal Display (LCD)
Liquid crystal display is one of the two technologies behind flat-panel displays, with the other being plasma technology. LCDs use two sheets of polarized material with a liquid crystal solution between them. As electricity is passed through the liquid, it causes the particles to align so that light cannot pass between them. Each crystal particle acts like a shutter, either allowing the passage of light or blocking it in order to form the image.
Resolution
Resolution is what determines the sharpness and clarity of the viewing image. It is expressed as the number of pixels from left to right (or columns) by the number of pixels from top to bottom (or rows). A resolution of 1024 x 768 indicates that the image or screen is 1024 pixels wide by 768 pixels high.
RGB
Acronym for red, green, and blue. This is used in reference to component signals produced to display color images by a traditional analog computer monitor and/or projector.
RS-232C
A type of connection cable to connect a computer to another medium.
Super VGA (SVGA)
Super VGA (SVGA) refers to a computer signal that is of a higher resolution than the standard VGA resolution of 640 x 480.
Throw Distance
Throw distance is the distance from the lens of the projector to the center of the screen surface. It is expressed as a range to indicate the minimum and maximum distance in feet that the projector should be from its projection surface.
UXGA
A specific type of display resolution: 1600 x 1200
Video Graphics Array (VGA)
A specific type of display resolution, a standard for computer signals: 640 x 480
Viewing Angles
The maximum angle at which you can view your flat-panel display without the image appearing faded, weak, or distorted.
(E)xtended Graphics Adapter (XGA)
A specific type of display resolution: 1024 x 768
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