Interpress is a page description language developed at Xerox PARC, based on the Forth programming language and an earlier graphics language called JaM. PARC was unable to commercialize Interpress. Two of its creators, Chuck Geschke and John Warnock, left Xerox, formed Adobe Systems, and produced a similar language called PostScript. Interpress is used in some Xerox printers most notable was the DocuTech Network Production Publisher, and is supported in Xerox Ventura Publisher. Interpress is also used as the output format for PARC's InterScript system, which is an editable word processor format for rich text documents. Interpress describes the desired or ideal appearance of a document that has been completely composed by some other process (emitter). All line ending, hyphenation, and line justification decisions, and in fact all decisions about the shapes and positions of the images, are made before creating the master. Since Interpress describes a document in a device-independent manner, a master can be printed on a variety of devices, each of which renders its best approximation to the ideal represented by the master.