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. Movable metal type Typesetting involves the presentation of textual material in an aesthetic form on paper or some other media. ... A lens is: a part of the eye an optical device that may be used in a camera or in a telescope; see lens (optics). ... The Offset Printing process Offset printing is a widely used printing technique where the inked image is transferred (or offset) first to a rubber blanket, then to the printing surface. ... This article is in need of attention from an expert on the subject. ...

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 Compuwriter, used a filmstrip wrapped around a drum that rotated at several thousand RPM. The filmstrip contained two fonts (a Roman and a Bold or a Roman and an Italic) in one point size. 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. (Other manufacturers included Alphatype, Varityper and Mergenthaler). // Events and trends The 1940s were seen as a transition period between the radical 1930s and the conservative 1950s, which also leads the period to be divided in two halves: The first half of the decade was dominated by World War II, the widest and most destructive armed conflict in... The 1970s in its most obvious sense refers to the decade between 1970 and 1979. ... Hot type is a nickname for a type of printing, now largely superceded by computers, that involved creating words and pictures in blocks of alloy, usually lead, then using those blocks to apply the ink to paper. ... The Offset Printing process Offset printing is a widely used printing technique where the inked image is transferred (or offset) first to a rubber blanket, then to the printing surface. ...

The Compuwriter was replaced in 1975 by the Compuwriter IV (and 88, a stripped down model) which held two filmstrips, each holding four fonts (usually a Roman, Italic, Bold and Bold Italic). It also had a lens turret which had eight lenses giving different point sizes from the font.

The Compugraphc EditWriter series added floppy disk storage on an 8 inch 320K disk. This allowed the typesetter to make changes and corrections without rekeying and a new galley could be printed. There was also a CRT screen to view typesetting codes and text. It used the same four font filmstrip.

Some later phototypesetters utilized a cathode ray tube to project the image of letters onto the photographic paper. This created a sharper image, added some flexibility in manipulating the type, and eliminated potential damage to film media and lenses. The Compugraphic MCS (Modular Composition System) with the 8400 typesetter is an example of the CRT phototypesetter. This machine used fonts on an 8 inch floppy. Cathode ray tube employing electromagnetic focus and deflection Cutaway rendering of a color CRT The cathode ray tube or CRT, invented by Karl Ferdinand Braun, is the display device used in most computer displays, video monitors, televisions and oscilloscopes. ...

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. Later phototypesetters had multiple column features that allowed the typesetter to save pasteup time.

With the start of desktop publishing software, Trout Computing in California introduced VepSet which allowed Xerox Ventura Publisher to be used as a front end and wrote a Compugraphic MCS disk with typesetting codes to reproduce the page layout.

Phototypesetting was later superseded by imagesetters and laser printers. An imagesetter is an ultra-high resolution large-format computer output device. ... A laser printer is a common type of computer printer that produces high quality printing, and is able to produce both text and graphics. ...