This provides a bright and sharp image even in less shaded areas. The complexity of the case of rear projection is that behind the screen should be enough space for the projector. Yes, and at the appropriate distance from the screen – for imaging the desired size. Usually a small adjacent darkened room, with the gap in the wall, drawn-translucent projection screen. Not long ago, there were screens that support both types of projection at the same time. They are positioned as 'screens with a 360-degree' and more suitable for advertising at trade shows, than for regular use in the office or at home. Indeed, on one side of the image is a mirror that is not always acceptable. The format and size projection screens appeared long before the advent of video projectors – Born at the dawn of cinema.
And that led to such a variety of relationships of the parties. 1:1 square format. Universal format, allowing images to project-oriented both horizontally and vertically. On these screens are projected photo-slides, mounted in a square box. Picture format 3:2 (1.5:1).
As the name implies, the format of the screen corresponded to a standard format still picture. Video format 4:3 (1.33:1). Format familiar television frame standard definition SDTV. 16:9 widescreen format (1.78:1). The new format of high definition television HDTV. Widescreen 1.85:1. Common format for feature films. Cinescope 2.35:1. The most wide-format in the movie, only wider in the panoramic cinema. With regard to the video projection is meaningful to talk only about three formats – 1:1 4:3 and 16:9.