A Capsule History of Typesetting
By R. J. Brown
Typesetting from Wood
The earliest known printed books were produced using wooden blocks with the text carved on them which was then used as a printing plate. These "plates" were produced in much the same manner as those for wood engravings -- except instead of an "picture" carved into them, the actual text of a page of a book was carved into them.
Hot Metal Composition
By the middle of the 15th century movable type had been invented in Europe. The German printer, Johann Gutenberg, first demonstrated his invention in 1448. By 1462 Gutenberg's invention became accepted and the use of it spread throughout Europe. Movable type is also called foundry type or hot type. In foundry type, each piece of type was cast into a precise size from metal which was an alloy of lead, tin, and antimony. Each piece contained a raised image of a single letter, number, or other character. The block of metal that carried the raised image was called the body. The raised image that was inked for printing was called the face -- from this we get the term "typeface".
A distribution box was made up of many compartments. The box had enough compartments so that each letter, number, and character was assigned a specific compartment of their own. In setting type, letters were selected one at a time and lined up in what was called a composing stick until it was almost full. Then, by using pieces of type with no face on them, spaces between words were adjusted to bring the line to the required length. Each line was placed by hand in a larger box made especially for housing the type. The individual line were laid out exactly like the page of the newspaper was going to be -- except the type was backwards as if looking at it in a mirror.
In the beginning, printing from hand-set type, the type was inked and copies made directly from the type. When printing was finished, the type was taken apart, cleaned and returned to the distribution box for use another time. (Much later on, technology was invented to be able to make plates -- called "stereotypes" -- from which the actual printing was done.)
The first practical mechanized type casting machine was invented in 1884 by Ottmar Mergenthaler. His invention was called the "Linotype". It produced solid lines of text cast from rows of matrices. Each matrice was a block of metal -- usually brass -- into which an impression of a letter had been engraved or stamped. The line-composing operation was done by means of a keyboard similar to a typewriter. The depression of a single key released a matrice of a character from the magazine that stored 90 characters. After a few rows of matrices were assembled, it was transferred mechanically to a mold-making device.
Modern type alloy was forced into the mold against the matrices and hardened almost immediately. The result was a bar of metal of the desired length of line with raised letters where the molten metal filled the impressions of the letter in the matrices. After using the type for printing, it would be dumped back into a pot to be melted down for use again. This machine was much faster than human-hand-set typesetting and required less of a staff for typesetting.
A later development in line composition was the "Teletypewriter". It was invented in 1913. This machine could be attached directly to a Linotype or similar machines to control composition by means of a perforated tape. The tape was punched on a separate keyboard unit. A tape-reader translated the punched code into electrical signals that could be sent by wire to tape-punching units in many cities simultaneously. These duplicate tapes were used to operate line-casting machines like the Linotype. The first major news event to make use of the Teletypewriter was World War I.
The next improvement in typesetting methodology was that of photocomposition machines. These machines had disks of film which had all each letter of the alphabet, numbers, and characters on them. An individual disk or drum frequently contained two or more type styles, and many machines were designed to carry more than one disk or drum. By varying the distance between the character on the drum and the film, it was possible to use the same negative image to produce a wide range of type sizes.
As the photosetting machine operated, the disk or drum rotated at high speed in front of the lens. When the controlling tape called for a specific character, a flash of light from a stroboscopic light source projected a character onto the film at the instant the character appeared before the lens. The flash of light and the exposure of the film occurred so quickly that the moving negative was in effect stopped. After each character was projected, either the film carrier or the lens system moved so that character after character was projected and exposed side by side until the line was completed. The film was then advanced so that the next line of type was exposed. The process was repeated many times until the entire article or news story was typeset.
Cathode Ray Tube Composition
The early 1960's saw the next improvement in typesetting methods. This group of machines made use of a cathode ray tube (CRT) for photocomposition. In this process, the image of each character was created on the screen of a cathode ray tube similar to a television picture tube. This image was projected through a lens, where it formed a character of the appropriate size on light-sensitive paper or film.
The keyboarding function was separate from the typesetting function and resulted in a punched paper tape or a magnetic tape that contained the text matter and a series of codes describing the type face and style, size, and all other instructions required for typesetting. The tape was used to control the CRT photocomposition unit.
In several CRT photosetting machines, a final image of each character was stored in the composing unit. As a character was called for by the tape, a scanning device read the stored character and converted the information to electrical signals. These signals were transferred to a cathode ray tube where the image of the character appeared on the face of the tube. The image was projected through a lens at the desired size onto photosensitive paper or film.
In more advanced machines, the shape of each character was analyzed as bits of information and recorded magnetically in the computers' memory. This eliminated the need for a film image of each character. When a character was called for by the tape, the magnetic information was read and translated into electrical signals that caused the visual image of the character to appear on the cathode ray tube screen. With this system, a number of characters could be stored in magnetic memory and be called out at remarkable speed.
An advanced photocomposing method, adopted particularly in the newspaper industry and still in use today, is also based on the cathode ray tube. In such a system, a video display terminal has a keyboard on which copy is typed. The composition appears on the tube and is also stored in a magnetic memory. If a change is required, the writer types over the matter, the words disappear, and new ones take their place. Copy can be rolled back for review or change. When the copy is satisfactory, depression of a code button automatically transmits it directly to a computer for storage or a composition unit. Advanced video display terminals can control the size and spacing of type at the touch of a key button, eliminating time-consuming physical movement of hot metal type or photocomposed matter.
In all advanced composition systems many functions in typesetting are handled by computer. They include justification of lines of type, hyphenation of words, and calculations of page depths.
Considering the sophistication of previous computer-driven photo typesetting machines, it seemed only logical that the next step involves laser optics to drive a printer. Using scientific technology not available even ten years ago, we can now do typesetting with the aid of laser beams.
Since the heart of all laser printers is an ordinary office photocopier, a brief description of how photocopiers work is in order. In a copier, a very bright light is reflected off the white portions of a page onto an electrically charged, photosensitive drum. This procedure temporarily eliminates the electric charge in those areas of the drum that correspond to the white areas of a page. Fine grains of oppositely charged plastic bits, called toner
, are then applied to the drum. The toner sticks to the portions unaffected by the light. The toner is then transferred to the paper.
With a laser printer, first text, headlines, and so forth, are entered into a computer by means of a computer word processing software program. When ready to have a copy printed, a special computer chip within the printer then projects the text onto the drum. a laser beam replaces the reflected light used in a ordinary photocopier. The laser doesn't move, but the beam is directed rapidly across the width of the drum by a spinning mirror. Each time the light reflects onto the drum, areas that would correspond to the white portions of the paper, become temporarily uncharged. From this point on the laser printer acts like a photocopier. Expensive photosensitive paper is no longer needed.
Using other systems of typesetting, a lot of time is spent positioning on a layout board the many single columns of text the system produced. With laser printers, and page layout software programs, almost all of the "cutting and pasting" is eliminated. Rather, it's done within the computer and laser printer system. Today, the majority of newspapers in America are produced using computers and laser printers or higher resolution laser film based laser printers.