PostScript is a page description language (PDL English, page description language), used in many printers and conventional manner, such as transport format graphics files in professional print shops. It is based on the work done by John Gaffney at "Evans & Sutherland" in 1976. The PostScript concept differed fundamentally by using a full programming language to describe a print image. Image that would later be printed on a laser printer or other output device quality, rather than a series of escape sequences of low level (this seems to Emacs, which exploded internal concept similar with respect to editing).
Simple graphic format in color. Use 24 bits per pixel: 8 for red, 8 for green, 8 for blue if the maximum gray value is 255, uses 16 bits for red, 16 for green and 16 for blue if the value is greater than 255 and less than 65536. a PPM file is plain text and can be modified with a single processor, there is also not readable binary version of word processing normally. It is related to the PGM (grayscale) and PBM formats (black and white).