Phototypesetting

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Phototypesetting is a method of setting type, rendered obsolete with the popularity of the personal computer and desktop publishing software, that uses a photographic process to generate columns of type on a scroll of photographic paper. Typesetters used a machine called a phototypesetter, which would quickly project light through a film negative image of an individual character in a font, through a lens that would magnify or reduce the size of the character onto film, which would collect on a spool in a light-tight canister. The film would then be fed into a processor, a machine that would pull the film through two or three baths of chemicals, where it would emerge ready for paste up.

[edit] History

Phototypesetting (sometimes referred to as "cold type") dates back to the 1940s, but the technology became popular in the early 1970s when it replaced metal typesetting as offset lithography printing grew in popularity. A number of hot-metal equipment manufacturers (Mergenthaler Linotype, for example) began adapting their technology, while other companies like Alphatype and Varityper formed as a result of new printing technology demand.

Compugraphic produced phototypesetting machines in the 1970s made it economically feasible for a number of small publications to set their own type professionally. One model, the Compugraphic Compuwriter, used a filmstrip wrapped around a drum that rotated at several hundred RPM. The filmstrip contained two fonts (a Roman and a Bold or a Roman and an Italic) in one point size. To get different sized fonts, the typesetter loaded a different font strip or used a 2x magnifying lens built into the machine which doubled the size of font. The CompuWriter II automated the lens switch and let the operator use multiple settings. Other manufacturers of photo compositing machines included Alphatype, Varityper and Mergenthaler.

In 1975, the Compuwriter IV, as well as the Compuwriter 88, a stripped down version, held two filmstrips, each holding four fonts. (Usually a Roman, Italic, Bold, and Bold Italic font). It also had a lens turret which had eight lenses giving different point sizes from the font, generally 8 or 12 sizes, depending on the model. The low-end offered sizes from 6 to 36 point, while the high-end models went to 72 point. The Compugraphic EditWriter series took the Compuwriter IV configuration and added floppy disk storage on an 8-inch, 320K disk. This allowed the typesetter to make changes and corrections without rekeying. A CRT screen let the user view typesetting codes and text.

Because early generations of phototypesetters couldn't change text size and font easily, many composing rooms and print shops had special machines designed to set display type or headlines. One such model was the PhotoTypositor, manufactured by Visual Graphics Corporation, which let the user position each letter visually and thus retain complete control over kerning. Compugraphic's model 7200 used the "strobe-through-a-filmstrip-through-a-lens" technology to expose letters and characters onto a thin strip of phototypesetting paper that was then developed by photo-processor.

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 created the ability to offer a continuous range of point sizes by eliminating film media and lenses. The Compugraphic MCS (Modular Composition System) with the 8400 typesetter is an example of the CRT phototypesetter. This machine loaded digital fonts into memory from an 8-inch floppy. Additionally, the 8400 was able to set type in point sizes between 5 and 120 point in 1/2-point increments. It was extremely fast and was one of the first output systems (the other was also a Compugraphic machine, the 8600) that was able to output camera-ready output with a maximum width of 12 inches.

Early machines had no text storage capability; some machines only displayed 32 characters in uppercase on a small LED screen and spellchecking was not available.

Proofing typeset galleys was an important step after developing the photo paper. 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. Paste-up artists played an important role in creating production art. Later phototypesetters had multiple column features that allowed the typesetter to save paste-up time.

Early electronic typesetting programs were designed to drive phototypesetters, most notably the Graphic Systems CAT phototypesetter that troff was designed to provide input for. Though such programs still exist, their output is no longer targeted at any specific form of hardware.

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.