Printing Processes

The var­i­ous process­es in use dur­ing the twen­ti­eth cen­tu­ry are described in How it Works: Print­ing Process­es, repro­duced on the Pro­duc­tion Meth­ods page by kind per­mis­sion of Lady­bird Books.

Typesetting

The era of hand com­po­si­tion last­ed from Gutenberg’s time until well into the twen­ti­eth cen­tu­ry for some types of print­ing, notably job­bing work. Com­po­si­tion is the plac­ing of indi­vid­ual pieces of type, each of which rep­re­sents a let­ter, fig­ure, space, punc­tu­a­tion or oth­er mark, into a hold­er known as the ‘com­pos­ing stick’, fol­low­ing the hand- (or lat­er type-) writ­ten original.

Dur­ing the mid-19th cen­tu­ry, machines to mech­a­nise the process of com­pos­ing type and redis­trib­ut­ing it after use were patent­ed but they need­ed so many oper­a­tors that no advan­tage over hand com­po­si­tion was gained. Hot-met­al sys­tems were devel­oped at the end of the 19th cen­tu­ry which final­ly solved the prob­lems of com­bin­ing type­cast­ing, set­ting and dis­tri­b­u­tion with­in a sin­gle sys­tem, and speed­ed up the process suf­fi­cient­ly that hand com­po­si­tion was lareg­ly super­seded. These meth­ods enabled a sin­gle oper­a­tor to set approx­i­mate­ly three times as much text in the same time as a com­pos­i­tor work­ing by hand, and removed the need for the time-con­sum­ing task of redis­trib­ut­ing the type back into the cas­es after use.

Lino­type machines, invent­ed by Ottmar Mer­gen­thaler (1854–1899) and James Cle­phane (1842–1910) were first demon­strat­ed in 1886, and were man­u­fac­tured com­mer­cial­ly from 1890. Lino­type com­bines set­ting and cast­ing in a sin­gle ‘hot-met­al’ machine, oper­at­ed from a keyboard.

Mono­type is the sys­tem invent­ed by Tol­bert Lanston (1844–1913) in the 1880s. The prin­ci­ples behind its oper­a­tion were sim­i­lar to those of the Lino­type, but two sep­a­rate units were involved, and let­ters and spaces were cast as indi­vid­ual pieces of type. The com­pos­i­tor sat at a key­board, select­ing the appro­pri­ate key for the char­ac­ters and spaces in the text to be set. On com­ple­tion, the paper roll was trans­ferred to the cast­er oper­at­ed by an atten­dant. The Mono­type sys­tem was used main­ly for book work, and from 1922, the Mono­type Cor­po­ra­tion employed the dis­tin­guished typog­ra­ph­er, Stan­ley Mori­son (1889–1967) as an advi­sor and as well as intro­duc­ing his most famous font, Times New Roman. The Cor­po­ra­tion also com­mis­sioned high qual­i­ty fonts from design­ers such as Eric Gill, Fred­er­ic Goudy and Bruce Rogers.

A third sys­tem of mechan­i­cal com­po­si­tion, which was used main­ly for dis­play work and job­bing print­ing, rather than news­pa­per and book print­ing. The Lud­low Typo­graph dates from the ear­ly years of the twen­ti­eth cen­tu­ry and is best described as ‘semi-mechan­i­cal’. The matri­ces are assem­bled by hand into a com­pos­ing stick, and jus­ti­fied in more or less the same way as type is set by hand com­po­si­tion, but instead of the com­plet­ed stick being slid onto a gal­ley, the com­posed stick forms a matrix from which the slug of type is cast in the cast­er, which ejects the trimmed slug into the gal­ley. The matri­ces are then dis­trib­uted by hand.

Mechan­i­cal com­po­si­tion using one or oth­er of these sys­tems formed the basis of most print­ing oper­a­tions until the rise of pho­to­type­set­ting in the 1960s and 1970s. You can watch film of Lino­type (main­ly used in news­pa­per print­ing) and Mono­type (used in the book trade) machines in operation.

Pho­to­set­ting or pho­to­type­set­ting: these terms cov­er the arrange­ment of type made with­out the use of actu­al met­al type. Exper­i­ments with pho­to­graph­ic meth­ods of repro­duc­tion avoid­ing the use of met­al began in the ear­ly twen­ti­eth cen­tu­ry, based on pho­to­graph­ic meth­ods of repro­duc­ing illus­tra­tions. Today such meth­ods are based on the use of com­put­ers. The text can be typed in at a key­board or scanned using opti­cal char­ac­ter recog­ni­tion technology.

Printing machines

The press in use in Gutenberg’s time was very sim­i­lar to those used for cheese­mak­ing, or to press grapes for wine­mak­ing, and was made of wood: it remained fun­da­men­tal­ly unchanged for around 350 years. The forme of type was placed hor­i­zon­tal­ly on the ‘bed’ of the press and the paper, one sheet at a time, was placed in a parch­ment cov­ered frame called the tym­pan. The mar­gins of the paper sheet were pro­tect­ed by a cut out sheet called a frisket. Once ink had been applied to the type, the tym­pan and frisket were fold­ed down to lie flat over the forme, and the whole bed was slid under a flat plate, the plat­en, which was attached to a screw. Pres­sure was applied to this by the press­man pulling on a bar which act­ed on a screw and low­ered the plat­en onto the paper and type. The amount of pres­sure that could be applied in this way was lim­it­ed by the strength of the wood­en frame.

One of the ear­li­est improve­ments in let­ter­press print­ing at the begin­ning of the nine­teenth cen­tu­ry was the devel­op­ment of iron press­es. The ear­li­est British ver­sion, the ‘Stan­hope’ was named after its inven­tor, Earl Stan­hope, and the ‘Columbian’ was first con­struct­ed in Philadel­phia by George Cly­mer short­ly after­wards. The Albion press was devel­oped in Lon­don in the 1820s, by R W Cope. There is more infor­ma­tion on lat­er devel­op­ments on the Print­ing Machin­ery page.

The distinction between direct and offset printing

All print­ing meth­ods are either direct or off­set. Print­ing from forme to paper with no inter­ven­ing stage, as in let­ter­press is a ‘direct’ print­ing sys­tem. Off­set print­ing is plano­graph­ic process (such as lith­o­g­ra­phy) in which the print­ing plate makes an impres­sion on a rub­ber sheet or roller, and the image is then trans­ferred from the sheet or roller onto the paper. ‘Off­set’ is usu­al­ly asso­ci­at­ed with lith­o­graph­ic printing.

Litho stone

Orig­i­nal­ly lith­o­g­ra­phy: orig­i­nal­ly this meant lit­er­al­ly print­ing from the stone, a process dis­cov­ered in 1796 by Aloy­sius Sene­felder. The basis of this sys­tem of print­ing is the mutu­al repul­sion of oil and water: a greasy image attracts the ink, which is repelled by the sur­face of the water bear­ing stone. With­in a few years, Sene­felder had dis­cov­ered that the same prin­ci­ple could be applied to print­ing from met­al plates: all sub­se­quent devel­op­ments of lith­o­g­ra­phy, using met­al and more recent­ly plas­tic and poly­mer plates, have con­tin­ued on the same principle.

The process of print­ing by lith­o­g­ra­phy off­set onto paper was devel­oped by Ira W Rubel of New York in 1904, and over the fol­low­ing cen­tu­ry it became the main print­ing process in use. The print­ing plates are usu­al­ly met­al (zinc or alu­mini­um): the sur­face is not left smooth, but is giv­en a fine­ly grained tex­ture, and when the inked image is print­ed down onto the plate, it is treat­ed with chem­i­cals to increase its ten­den­cy attract the greasy ink, while the non-inked areas are treat­ed to increase their capac­i­ty to absorb water. The sys­tem is used for text and illus­tra­tion, and for both mono­chrome and colour printing.

Pho­to-litho com­bines pho­tog­ra­phy and lith­o­g­ra­phy. A neg­a­tive of the orig­i­nal text or illus­tra­tion is made: a ruled screen is used for pho­tographs of illus­tra­tions with tones. The neg­a­tive is print­ed down onto a lith­o­graph­ic plate, and is print­ed by the off­set litho process.

Illustrations

Wood­cuts were the ear­li­est form of print­ed illus­tra­tions. The design is drawn or traced in reverse on the plank grain of a block of soft wood, and is cut away by the artist using carv­ing tools, so that the design is left in relief and the oth­er areas area cut away. The result is bold lines with a white background.

The tech­nique of wood engrav­ing was devel­oped by Thomas Bewick at the end of the eigh­teenth cen­tu­ry. It dif­fers from wood­cuts in that the design is excised below type height. The sur­face of a block of hard wood is pre­pared and the design is then traced in reverse on the end grain. Steel grav­ing tools of the kind used by met­al engravers are used to excise the design: the sur­face of the wood receives the ink and the design is print­ed as a white design on a black back­ground. Tones in the back­ground can be achieved by the skil­ful use of lines and dots.

Engrav­ing had been used as an intaglio print­ing process for many years before this. In intaglio process­es, the design is cut into a met­al plate, and the ink is held in these grooves, in con­trast to relief print­ing process­es such as let­ter­press and wood­cut. These can be etched or engraved with sharp tools.

There are var­i­ous types of etch­ing, but the basis of all these meth­ods is sim­i­lar. A met­al plate, usu­al­ly cop­per or zinc is cov­ered with a ground, the com­po­si­tion of which varies depend­ing on the type of illus­tra­tion required, and the back and sides of the plate are pro­tect­ed with a coat of var­nish. The draw­ing is repro­duced in reverse on the plate. The lines are then excised with a suit­able tool to expose the met­al, and the plate is dipped in a bath of acid to incise the lines of the design in the plate. Once the lines reach the required depth they are var­nished over, and the plate can be dipped again until all lines have been incised to the required depth.

Pho­togravure is an intaglio process which orig­i­nat­ed in the work of Karl Klič (1841–1926) in the late 1870s. It was first intro­duced into the UK by the firm of T & R Annan of Glas­gow in 1883. The image to be repro­duced is pho­tographed through a screen which marks the image into cells. From the neg­a­tive, a con­tin­u­ous tone pos­i­tive is then pro­duced from the neg­a­tive, and print­ed down onto a car­bon tis­sue sheet. The image is then trans­ferred to the print­ing sur­face and devel­oped. A con­tin­u­ous tone print is then pro­duced by print­ing from the plate once the design has been etched. The areas etched to the deep­est lev­els, showed dark­est, and the pat­tern of cells hold the ink. A ‘doc­tor blade’ removes the sur­plus ink from the sur­face of the plate. In the 1890s Klič adapt­ed the process to allow for print­ing from rotary plates.

News­pa­per illus­tra­tions were often pro­duced using the half-tone process. The orig­i­nal is pho­tographed through a ruled glass screen to pro­duce a pat­tern of dots: the dots are of vary­ing size, but equal­ly spaced across the area to be print­ed. Once the neg­a­tive has been devel­oped it is print­ed onto the print­ing sur­face. The larg­er dots rep­re­sent the dark­er shades, and when viewed nor­mal­ly pro­duce the opti­cal illu­sion of dark tones, but the dots can be seen through a mag­ni­fy­ing glass.

The pho­to-engrav­ing process is also known as ‘let­ter­press platemak­ing’ or ‘process engrav­ing’ and can be used to repro­duce any kind of orig­i­nal, in either mono­chrome or colour. The print­ing sur­face is in relief, and it is use­ful for illus­tra­tions which are close­ly com­bined with text.