Da-Lite > Educational Materials > Selecting Front Projection Screens for Today's Presentation Applications Screen Borders One important aspect of front projection screens often minimized or overlooked, is black masking borders or more commonly known as screen borders. This feature provides a crisp edge to any screen surface and is almost always constructed of a non-reflective black material. Borders are used for a number of different reasons. One, perceived brightness of an image on a screen is relative to the light projected on the screen when compared to the surrounding background. For example, if you placed a screen up against a white wall in a darkened room, the image would likely appear dull and lifeless. However, by incorporating a black border around the screen, the human eye perceives the image to have more contrast and a sharper picture with brighter colors. The eye is comparing the projected image with the black border, not the background. In an ideal world, projection equipment would project an image to the exact dimensions of a screen without keystoning. Unfortunately, that's not the case. Borders help to hide flaws in a projected image by masking out unevenness caused by out-of-level equipment, images improperly framed due to focus limitations or distance from the screen, and slight keystoning caused by the projection image not being aligned 90 degrees to the screen. Serious keystoning as typically found in overhead projectors however, can only be corrected by either raising the height of the projector or purchasing a screen that tilts slightly downward. Screens with keystoning correction devices are widely available. Depending on the screen surface, borders are available for all four sides of a screen or just on the vertical sides. If the screen surface is to be used exclusively for a projection method with a set aspect ratio (i.e. video format 1.33), then, if available, purchase a screen surface with borders on all four sides. If the screen will be used for a differing range of projection methods with a variety of aspect rations (i.e. slides), then purchase a screen with borders only on the vertical sides and adjust the screen drop to reduce the unused portion of the screen surface. <--previous page introduction glossary next page --> For pricing information, please contact Media Fabricators, Inc. via e-mail at [email protected] or via telephone at 323 937 3344.