Originally these programs were used to generate 35 mm slides, to be presented using a slide projector. As these programs became more common in the late 1980s, several companies set up services that would accept the shows on floppy disk and create slides or print transparencies. In the 1990s, dedicated LCD-based screens that could be placed on the projectors started to replace the transparencies, and by the late 1990s they had almost all been replaced by video projectors.