Phototypesetting
|
|
Phototypesetting is a method of setting type with light (photo). It consists of a character matrix in the form of film negative which has the images of all the characters, a light-sensitive paper and a light source. The characters in the matrix are exposed to the photographic paper by the light source through a lens one by one as they are typed on the keyboard, using a similar mechanism to that of a typewriter. The exposed photographic paper is developed and used as master for reproduction of plates, which are required for the printing process (offset lithography). The different fonts are achieved by having a character matrix for each font. Differences in the sizes of the characters are achieved by adjusting the lens unit.
History
Phototypesetting dates back to the 1940s, and it became popular in the early 1970s, when it replaced metal typesetting, with the growing popularity of offset lithography. CompuGraphic produced phototypesetting machines in the late 1970s. One model for example, the CompuGraphic 8400, used a filmstrip wrapped around a drum that rotated at several thousand RPM. By using a strobelight and tracking the position of letters on the filmstrip, characters were exposed onto photopaper as the filmstrip drum moved across the photopaper, creating justified or unjustified text. To get different-sized fonts, the typesetter had to put in a different font strip or use a 2x lens built into the machine which simply doubled the size of font.
Early machines had no text storage capability; some machines only displayed a few words on a small LED screen and spellchecking was not available. Proofing typeset galleys was an important step after developing the photopaper. Corrections could be made by typesetting a word or line of type and by waxing the back of the galleys, and corrections could be cut out with an X-Acto knife and pasted on top of any mistakes.
Since most early phototypesetting machines could only create one column of type, long galleys of type were pasted onto layout boards in order to create a full page of text for magazines and newsletters. Pasteup artists played an important role in creating production art.
Phototypesetting was later superseded by imagesetters and laser printers.ru:Фотонабор