These Presentation Media criteria are as follows:
CRT Technology – A video projection system using three-tube projectors (one for red, green and blue)
with a fixed focal length and are usually lower in light output. Alignment of the three tubes is critical for
best resolution and color rendition.
LCD Technology – This technology uses a conventional light source, usually a halide arc lamp, to project an image by passing light through three internal liquid crystal displays–one each for red, green and blue. Each image is then combined by a series of mirrors into a single image.
DLP Technology – This technology is based on the Digital Micromirror Device™ (DMD™) which uses over 500,000 microscopic mirrors on the SVGA chip to reflect images on screen.
D-ILA Technology – In this technology, light is reflected off a mirror surface located under the LCD pixel layer. This reflective process results in higher brightness and contrast levels.
LCOS Technology – LCOS devices have crystals coated over the surface of a silicon chip, which is coated with a reflective surface. Polarizers are located in the light path both before and after the light bounces off of the chip.
35MM Slide Transparency – One of the most popular methods of displaying single-frame photography. Like other portable film projection methods the slide’s continuous tone properties and the projector’s high light output (varying from 1000 to 6000 lumens), provide an excellent image–showing fine detail and exceptional color rendition.
Overhead Transparency – In business and educational settings, the overhead projector is still a popular projection choice. Its flexibility, ease of use and high output light source of approximately 3000 lumens provides a projection method individual presenters can use in their own personal manner.
Three-dimensional and specialty projection–The polarization of images to produce three dimensional images substantially reduces light output dictating a much higher gain screen than any other form of projection. Also, some front-projection screen surfaces actually disrupt the polarization effect.
Some special video projection situations require a higher contrast due to high ambient light conditions. In these cases, a curved screen is sometimes recommended.