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{{Short description|Mechanical analog method for text composition}}
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[[File:Linotype operators of the Chicago Defender.png|thumb|300px|Row of Linotype operators at the ''[[Chicago Defender]]'' newspaper, 1941]]
{{History of printing}}
In [[printing]] and [[typography]], '''hot metal typesetting''' (also called '''mechanical typesetting''', '''hot lead typesetting''', '''hot metal''', and '''hot type''')
It was the standard technology used for mass-market printing from the late nineteenth century until the arrival of [[phototypesetting]] and then electronic processes in the 1950s to 1980s.<ref name="Monotype and Phototypesetting">{{cite journal|last1=Boag|first1=Andrew|title=Monotype and Phototypesetting|journal=Journal of the Printing History Society|date=2000|pages=57–77|url=http://www.letterpress.ch/APINET/IMMPDF/MONOPHOTO/PHS_journal.pdf|access-date=22 July 2016|archive-url=https://web.archive.org/web/20160328052034/http://www.letterpress.ch/APINET/IMMPDF/MONOPHOTO/PHS_journal.pdf|archive-date=28 March 2016|url-status=dead}}</ref><ref name="Guardian 1987">{{cite web|last1=Narewska|first1=Elli|title=The end of hot metal printing: GNM Archive teaching resource March 2015|url=https://www.theguardian.com/gnmeducationcentre/2015/mar/03/end-of-hot-metal-printing-gnm-archive-teaching-resource|website=[[The Guardian]]|date=3 March 2015|access-date=20 August 2017}}</ref><ref name="Golding">{{cite news|last1=Golding|first1=Emma|title=Making headlines: printing the Guardian newspaper, 1921-1987 - in pictures|url=https://www.theguardian.com/gnm-archive/gallery/2016/nov/18/making-headlines-printing-the-guardian-newspaper-1921-1987-in-picures|website=[[The Guardian]]|date=18 November 2016|access-date=20 August 2017}}</ref>
== Types of typesetting ==▼
==History==
Two different approaches to mechanising typesetting were independently developed in the late 19th century. One, known as the [[Monotype Corporation|Monotype composition caster]] system, produced texts with the aid of perforated paper-ribbons, all characters are cast separate. These machines could produce texts also in "large-composition" up to 24 point.▼
Hot metal typesetting was developed in the late nineteenth century as a development of conventional cast metal type.<ref name="Cold type vs. hot typesetters">{{cite web|last1=Kupferschmid|first1=Indra|title=Cold type vs. hot typesetters|url=http://www.alphabettes.org/cold-type-vs-hot-typesetters/|website=Alphabettes|date=9 November 2012 |access-date=20 August 2017}}</ref> The technology had several advantages: it reduced labour since type sorts did not need to be slotted into position manually, and each casting created crisp new type for each printing job. In the case of [[Linotype machine]]s, each line was cast as a robust continuous block (hence "line o'type") which was useful for rapid newspaper printing.
▲== Types of typesetting ==
▲Two different approaches to mechanising typesetting were independently developed in the late 19th century. One, known as the [[Monotype
The Super-caster, another machine produced by Monotype, was similar in function to the Thompson,
The other approach was to cast complete lines as one slug, usually comprising a whole line of text.
Of this system there
* [[Linotype machine|Linotype]]
* [[Intertype Corporation]]
* the [[John Raphael Rogers|Typograph]], produced in Germany
* [[Ludlow Typograph]]▼
* The Monoline, a very basic machine
The Linotype and similar Intertype machines came out with paper tape and electronic automation near the end of their
While the other machines were operated by (non-QWERTY) keyboards, in the [[Ludlow Typograph]] the matrices for each line were assembled in a stick by hand. This machine was able to cast display body sizes that other mechanical composition systems were unable to produce. In this way headings could be produced to complement text produced on other machines. It also used the same alloy as Linotype machines, so was a useful adjunct to page makeup for newspapers as, when
The success of these machines lay in different fields
▲* [[Ludlow Typograph]]
▲This machine was able to cast display body sizes that other mechanical composition systems were unable to produce. In this way headings could be produced to complement text produced on other machines. It also used the same alloy as Linotype machines, so was a useful adjunct to page makeup for newspapers as, when complete, all the metal could be remelted without having to be separated or the type from the headings redistributed back into case.
▲The success of these machines lay in different fields: the Monotype caster was more popular for bookwork that required the ability to make manual corrections and edits while the slug casting systems found success in newspaper production where speed of production and make ready for print was essential.
▲There is another essential difference between Monotype and all the "slug"-producing machines: a Monotype machine functions with a minimal set of matrices: each character needs one matrix. Linecasters cannot function this way, and these systems need quite large magazines of matrices to be able to set a complete line of text with the usual character repetitions. Indeed, the nominal 90 channel magazine of a linecaster really has 91 total channels, with the first two channels allocated to the lower case 'e', and with these matrices being alternately selected from channel 0 or channel 1, for alternate lines of cast type.
▲There is an additional difference: Monotype ''must'' use a punched paper tape, and the "reading frame" is always backwards (right-to-left) in order to achieve [[Typographic alignment|justification]], as justification is not an inherent capability of the machine (however, "flush left" ''is'' an inherent capability); whereas Linotype ''may'' use a punched paper tape, although this option is seldom-used outside of daily newspapers, and whether a tape is used, or not, the "reading frame" is always forwards (left-to-right), with justification being an inherent capability of the machine (and, "flush right", "centered" and "flush left" may be very easily accommodated manually, or automatically using a "quadder" attachment).
=== Linotype ===
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Once a key is pressed, the matrix passes through what is known as the ‘assembler front’, down past a rotating fiber reinforced wheel (known as the star wheel) and into the ‘assembling elevator’ which serves the same purpose as the hand compositor's stick. When the space band key near the keyboard is pressed, one of the space bands drops out of the box and almost directly into the assembling elevator. The assembling elevator (or more commonly just the ‘assembler’) is adjustable for different lengths of line (in [[Pica (typography)|picas]]).
Once the line approaches its correct length, the operator is made aware of this by a bell or other indicator. If the line is ‘loose’ or too short, there is too much ‘white space’ for the space band wedges to fill out the line, and the matrices could possibly turn sidewise or fail to seal against each other as the machine prepares for the casting operation. If the line is ‘tight’ or too long, the elevator carrying the matrices and space bands will not seat properly in front of the mold slot. Both the Linotype and Intertype machines have two important safeties that act during the casting operation
When the line is assembled to the correct length, the operator presses down on a lever which raises the assembling elevator up into the delivery channel and starts the automatic casting cycle. The delivery channel transfers the matrices out of the assembler and into the first elevator. The first elevator then descends to a position in front of the mold, and if the elevator has not descended fully by the time the machine starts the process of aligning the matrices (most often caused by a ‘tight’ line), the first of the two safeties
With the matrices aligned and the space bands set to the correct measure, the machine then ‘locks up’ the line with great force and the plunger injects the molten type metal into the space created by the mold cavity and the assembled line. The machine then separates the mold disk (carrying the freshly cast slug), the metal pot, and the first elevator. The mold disk then turns to present the line at the ejecting position, in the process passing by a knife that trims the base of the slug to type height (0.918″ on US machines). The slug is then forced through an adjustable pair of knives to trim the slug to the proper body height before sliding down into a ‘galley’ of finished lines next to the operator. Depending on the model of machine, the mold disk could have
As the mold disk is turning, the first elevator simultaneously rises to its upper position and the space bands and matrices are vertically aligned in preparation for the second transfer. The matrices have a series of teeth in a V-shaped notch on top, and as the transfer is completed, the matrices slide onto the second elevator bar which carries the matrices by these V-shaped notches. The space bands, having no such notches, remain in the second transfer channel and are soon gathered by two levers and pushed back into the space band box. While the space bands are being pushed into their box, the second elevator continues rising towards the distributing mechanism at the top of the machine, which returns the molds to their proper places in the magazine. At the top of the machine, a lever (the distributor shifter) moves left to get in position to push the incoming line of matrices off the second elevator and into the distributor box. This mechanism feeds the matrices at precise intervals such that they travel between three rotating screws. Each matrix is carried along a notched bar between the three screws until the notches on the bar and matrix match, whereupon the matrix drops down into its proper channel in the magazine.
It was a source of pride for trained operators to boast of being able to ‘hang’ a line
The metal pot was kept filled by the operator tossing in small ingots of type metal every few lines, or later, by mechanical feeders that carry large ingots of type metal (and which often carried two ‘pigs’ at a time to be consumed in turn, the operator hanging a fresh one when one was consumed). These feeders are actuated by various methods (by cam, either elevator, or distributor shifter), but the
From time to time, the slug galley is transferred to the composing table to be set in the form, and once the press run is completed and the slugs removed from the form, they are tossed into the ‘hell box’ for remelting into new ingots. At intervals the lead is remelted and the oxidized metal (dross) skimmed off. As part of this process, ‘plus metal’ is added in the form of small ingots to replenish that portion of the alloyed metals that was lost by the formation of dross (by oxidization of the metal in the machine's pot or during the remelting stage). The type metal is poured into ingot molds
Funded largely by the [[Knight Ridder|Ridder]] newspaper interests, the [[Intertype Corporation]] developed ([[Wiktionary:circa|c.]] 1914) a compatible version of the Linotype machine when the patents ran out and it became quite popular as well. This led to a long-lasting legal fight by the Mergenthaler Linotype Company (who eventually lost).
Various methods were used to power the Linotype / Intertype machines, the most common being a fractional horsepower motor, one wired for single-phase 60 Hz alternating current eventually becoming the default offering. To accommodate the customers' requirements, motors were also built to be powered from direct current, 25 Hz AC, or 50 Hz AC circuits. Also, motors wound for various polyphase circuits (two-phase, 3-phase, wye, delta, etc.) were made available for the customers as well. In a few cases, where electricity was not available, it was possible to drive the machine by a belt connected to a [[line shaft]].
Initially, the metal pot was heated by gas (whether natural or '[[Coal gas|manufactured]]'), but an electric pot was later developed and which became a standard option. As with the motors, the control machinery for the metal pot heaters was produced in a variety of voltages and in direct or alternating current versions. For locations with access to neither gas or electricity, the gas-fired pot could be fitted with a burner kit to allow the use of kerosene or other '[[white gas]]' fuels.
Thus, regardless of the power sources available (within reason), it was possible to install a Linotype (or Intertype) machine in almost any newspaper office, whether in a remote mountain community or a downtown office in an urban metropolis.
=== Typograph and Monoline ===
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A manual linecasting solution known as the [[Ludlow Typograph]] also met with success because it was able to cast display type sizes that other mechanical composition systems were unable to produce.
The Ludlow consisted of a very heavy metal table with a flat top about waist high and a depressed slot into which a "stick" was inserted. Underneath was a pot of molten type metal and a plunger. The stick was used to hand compose the lines of type, typically headlines in 18 point or larger with 72 point commonly being available, but the machine could cast type from 4pt to 600pt without a mould change. This was from brass matrix stored in cases on either side of the Ludlow. The cases were not the traditional "[[California Job Case
After a line of type was assembled into the stick a special blocking slug was inserted to seal the end. Then the stick was placed mold side down into the slot on the table, a clamp locked down to securely hold the stick and the Ludlow activated. The plunger would snap down into the pot with considerable force, injecting molten type metal into the mold at a high
Towards the end of its life as a common [[backshop]] type setter, the Ludlow was often joined by the "Super Surfacer" a specially designed surface plane that would smooth the surface of the freshly cast type and ensure it was exactly type high. A Ludlow slug was just the letters overhanging a central spine about 12 points wide (T
The Elrod was a machine used to cast rules and spacing material (leading)
All these line-casting machines used various alloys near the [[eutectic]] point and which typically consisted of approximately 4% tin and 12% antimony and the balance being lead. These alloys were proportioned such that the type metal would solidify as rapidly as possible at the lowest possible freezing point.
=== Monotype ===
[[File:Matrixcase-bembo-16pts.jpg|thumb|right|A Monotype composition case showing
The [[Monotype System]] took a different direction in hot metal typesetting, with the ability of the Composition Caster to cast loose type using a paper tape
This type was most times made of an alloy (8-10%
The used type, like the slugs from line casters, was re-melted when no longer needed. Each time remelting caused some loss of
The [[Monotype Corporation]] survived the demise of the hot metal typesetting era by selling digital type.
== Transition ==
Towards the end of its life, hot metal composition in newspapers was kept alive by the proof press. As each page was set and locked up, it was moved on a turtle (a rolling table with an [[surface plate|accurately flat]] steel surface)<ref>{{cite web|url=http://www.printerhistory.com/lore.html |archive-url=https://web.archive.org/web/20031212054328/http://www.printerhistory.com/lore.html |url-status=dead |archive-date=12 December 2003 |title=A Few Words About Words |publisher=Pressed for Time |
Black paper was inserted before the proof was photographed for each of the photos on the final page to create clear windows in the negative. The separately made [[halftone]]s would be taped into these clear windows on the negative. This negative could then be used to expose the photosensitized printing plate for an [[offset printing|offset press]]. In this way the heavy investment in hot metal typesetting could be adapted to the newer offset technology during a transition period.
Another [[synergy]] and transition mechanism was using paper tapes made for TTS systems (linotype) and monotype tapes directly by the photo typesetter system.
These tapes could be read and processed by many, maybe most optical setting systems. This allows avoiding actual use of metal, while preserving some of the value and investment in the "typesetting" and communication side of hot metal. Such systems were widely used in the later years of hot metal, and optical typesetting systems kept supporting and further developing TTS standard, alongside similar systems for most of the optical typesetting era.
== Comparison to successors ==
The nature of text printed via the hot-metal method is notably different from that produced by the [[phototypesetting]] processes that followed it. As the lead type used to print (letterpress) a page had been directly formed from the [[Matrix (printing)|type matrix]], a good fidelity to the original was achieved. Phototypesetting suffered (at least in its early days) from many problems relating to [[Distortion (optics)|optical distortion]] and misalignment. These disappointing results were a thorn in the sides of many authors and readers (especially of complex or mathematical texts that had many small sub- and superscripts). A desire to re-create the aesthetic qualities of hot lead spurred [[Donald Knuth]] to create one of the first general
Although
== References ==
{{
== External links ==
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{{Letterpress}}
{{Authority control}}
[[Category:Typography]]
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