they began to be used to render characters, columns, pages, and even multi-page signatures directly, rather than simply summoning a photographic template from a pre-supplied set. In addition to being used as display devices for computer operators, cathode ray tubes were used to render text for phototypesetting. The curved nature of the CRT display, however, led to distortions of text and art on the screen towards the outer edges of the screens. The advent of "flat screen" monitors (LCD, LED, and more recently OLED) in 1997 eliminated the distortion problems caused by older CRT displays. As of 2016 flat-panel displays have almost completely replaced CRT displays. Printers attached directly to computers allowed them to print documents directly, in multiple copies, or as an original which could be copied on a ditto machine or photocopier. WYSIWYG word processors made it possible for general office users and consumers to make more sophisticated page layouts, use text justification, and use more fonts than were possible with typewriters. Early dot matrix printing was sufficient for office documents but was of too low a quality for professional typesetting. Inkjet printing and laser printing did produce sufficient quality type, and so computers with these types of printers quickly replaced phototypesetting machines. With modern desktop publishing software such as flagship software Adobe InDesign and cloud-based Lucidpress, the layout process can occur entirely on-screen. (Similar layout options that would be available to a professional print shop making a paste-up are supported by desktop publishing software; in contrast, "word processing" software usually has a much more limited set of layout and typography choices available, trading off flexibility for ease of use for more common applications.) A finished document can be directly printed as the camera-ready version, with no physical assembly required (given a big enough printer). Greyscale images must be either half-toned digitally if being sent to an offset press or sent separately for the print shop to insert into marked areas. Completed works can also be transmitted digitally to the print shop, who may print it themselves, shoot it directly to film, or use computer to plate technology to skip the physical original entirely. PostScript and Portable Document Format (PDF) have become standard file formats for digital transmission. Digital media (non-paper) Since the advent of personal computing, page layout skills have expanded to electronic media as well as print media. E-books, PDF documents, and static web pages mirror