Projectors are used to projects the images on the surface of the wall or else in the darkroom. The projectors are various in their type based on their process of input. Accordingly, the projectors are categorized into three types. The video recorded a projector to project the prerecorded images but in the case of PowerPoint presentation, the still images are used to project. For the real-time input, it can be easily adopted with the video camera. For the projection of the still images, star , the magic lantern is the best-known item to select. Since its invention, the magic lantern was capable of projecting the images in the state of action from the mechanical slides. For the better action star projectors are the best choice. To project the moving images of ghosts, the magic lantern is reached its peak of popularity when it is used in the phantasmagoria which is the form of horror theatre.
Three different types of projector:
According to the action or the process of the projector, it has been classified into three types. And they were known to be, still images, real-time, moving images. These above are all the general classification of the projector as well those three types have their specifications. That they are classified as the still images is classified as, magic mirror, slide projection, the magic lantern, enlarger which is known for the production of the photographic prints, steganographic mirror. Those above given are the classification of the still image projector. For the real-time projector, it is classified into a document camera, camera obscura, opaque projector, concave mirror, overhead projector areas classified. For the moving image projector, virtual retinal display, video projector, handheld projector, trotting horse lamp, movie projector are all classified with the projection of the moving images.
History of 20th century to the present day:
Low-cost opaque projectors are produced and marketed in the early and middle parts of the 20th century as a toy for children. The limelight was used as the light source for the early opaque projector, later it was overtaken by halogen lamps. That is the incandescent light bulb is used in the earlier opaque projector. As the enlargement tool of the artist, the episcopes are still used which allow the images to be traced on surfaces. The surface can be the already prepared canvas for the trace of projection. Overhead projectors are widely in use in the late 1950s and the early part of the 1960s in the schools and businesses. In the police identification network firstly the overhead projectors are used and became familiar. Cellophane rolls are used in the overhead projector in the range of nine-inch stage that allows the facial characteristics which are rolled across the stage. In the year 1945, the United States Army was the first country to use the overhead projector in the large quantity to train for the world war the second look over the wound down. Slide projectors are invented from the 1950s to the 1960s that was with 35mm photographic positive films that are very common for the presentation and also in the form of entertainment aspects. Through this, the slideshow view is presented for the family gathering and friends gathering and typically for the vocational travels.