Projectors have been there since the start of the movie age. A white light obstructed by a Film that ads shares and color to it is made to hit a screen which reflects off the image for us to view.
That is completely out of now. No one is shooting movies or any video with Films or Video tapes, and everything is being done thru the digital media. Digital movie cameras are very tiny and light these days compared to the film cameras in the olden days, and undoubtedly, it produces a lot more quality and clarity than it used to in the 35 MM film.
Movie houses use a bigger kind of projectors these days, while we people at our homes rely on LCD projectors. These projectors used to come with 3 lenses, in 3 different colors, such as yellow, a shade of blue, and a shade of red. and used to project the tri color image on a screen, and right now these days we have a technology that helps projectros do that with just one single lens.
The only problems with these projectors are that they often require a change of the lamps. It is not an ordinary light bulb that you use at your homes that is used to lighten up the screen. It is usually an arc lamp only which you produces white light, and unlike the tungsten filament lamp, or the incandecent lamp, the life of these projector lamps are relatively low, and they require replacement often. But still you can save on discount projector lamps that are available in the market, and online.