PostScript has long been the standard for desktop publishing and digital graphic arts production. Adobe Systems developed PostScript as a Page Description Language (PDL). It is used primarily as a language that communicates to a printer exactly how a document is to be output. It is an object-oriented language, which means that instead of describing graphics, images, and text as bitmaps, it describes them as geometric shapes (vector graphics). Object oriented or vector graphics are well suited for high-resolution output devices because the print quality improves as the resolution of the output device improves. A bitmap image looks the same regardless of the resolution of the output device.
All PostScript printers contain interpreters that execute the PostScript output instructions. A PostScript file can be output on any PostScript printer without the need to open any application or fonts. The only requirement is that the printer has the "downloader utility" that comes with all PostScript printers.
PostScript file pages are imaged in order. Objects on a page may be dependent on the objects contained on a different page. A page that requires the same object that was downloaded on an earlier page cannot be printed without the earlier page. This means that there is no page independence.
PostScript technology isn't necessarily the best choice for the digital workflow or CTP printing. Service bureaus and print providers need reliability and consistency of workflow. They usually receive document files in the original authoring applications. The file goes through a workflow based on PostScript language or other formats. This can lead to problems because the flexibility of PostScript allows different applications to generate PostScript in many different ways. There is not as much consistency with PostScript as there is with PDF.