Editing ASCII art (section)

===Overprinting (surprint)===
In the 1970s and early 1980s it was popular to produce a kind of text art that relied on overprinting. This could be produced either on a screen or on a printer by typing a character, backing up, and then typing another character, just as on a typewriter. This developed into sophisticated graphics in some cases, such as the [[PLATO (computer system)|PLATO]] system (circa 1973), where superscript and subscript allowed a wide variety of graphic effects. A common use was for [[emoticon]]s, with WOBTAX and VICTORY both producing convincing smiley faces.<ref>[http://www.platohistory.org/blog/2012/09/plato-emoticons-revisited.html PLATO Emoticons, revisited], Brian Dear, ''[http://www.platohistory.org/ PLATO History: Remembering the future],'' 19 September 2012</ref> Overprinting had previously been used on typewriters, but the low-resolution pixelation of characters on video terminals meant that overprinting here produced seamless pixel graphics, rather than visibly overstruck combinations of letters on paper.

Beyond pixel graphics, this was also used for printing photographs, as the overall darkness of a particular character space dependent on how many characters, as well as the choice of character, were printed in a particular place. Thanks to the increased granularity of tone, photographs were often converted to this type of printout. Even manual typewriters or [[daisy wheel printer]]s could be used. The technique has fallen from popularity since all cheap printers can easily print photographs, and a normal text file (or an e-mail message or Usenet posting) cannot represent overprinted text. However, something similar has emerged to replace it: shaded or colored ASCII art, using ANSI video terminal markup or color codes (such as those found in [[HTML]], [[Internet Relay Chat|IRC]], and many internet [[message board]]s) to add a bit more tone variation. In this way, it is possible to create ASCII art where the characters only differ in color.