Printing is a process for reproducing text and images using a master form or template. The earliest non-paper products involving printing include cylinder seals and objects such as the Cyrus Cylinder and the Cylinders of Nabonidus. The earliest known form of printing as applied to paper was woodblock printing, which appeared in China before 220 A.D. Later developments in printing technology include the movable type invented by Bi Sheng around 1040 AD and the printing press invented by Johannes Gutenberg in the 15th century. The technology of printing played a key role in the development of the Renaissance and the scientific revolution, and laid the material basis for the modern knowledge-based economy and the spread of learning to the masses.

Woodblock printing

Woodblock printing is a technique for printing text, images or patterns that was used widely throughout East Asia. It originated in China in antiquity as a method of printing on textiles and later on paper. As a method of printing on cloth, the earliest surviving examples from China date to before 220 A.D.
Movable-type printing
Movable type is the system of printing and typography using movable pieces of metal type, made by casting from matrices struck by letterpunches. Movable type allowed for much more flexible processes than hand copying or block printing.

Around 1040, the first known movable type system was created in China by Bi Sheng out of porcelain. Bi Sheng used clay type, which broke easily, but Wang Zhen by 1298 had carved a more durable type from wood. He also developed a complex system of revolving tables and number-association with written Chinese characters that made typesetting and printing more efficient. Still, the main method in use there remained woodblock printing (xylography), which "proved to be cheaper and more efficient for printing Chinese, with its thousands of characters".

Copper movable type printing originated in China at the beginning of the 12th century. It was used in large-scale printing of paper money issued by the Northern Song dynasty. Movable type spread to Korea during the Goryeo dynasty.

Around 1230, Koreans invented a metal type movable printing using bronze. The Jikji, published in 1377, is the earliest known metal printed book. Type-casting was used, adapted from the method of casting coins. The character was cut in beech wood, which was then pressed into a soft clay to form a mould, and bronze poured into the mould, and finally the type was polished. The Korean form of metal movable type was described by the French scholar Henri-Jean Martin as "extremely similar to Gutenberg's". Cast metal movable type was spread to Europe between the late 14th century and the early 15th century.

The printing press

Around 1450, Johannes Gutenberg introduced the first movable type printing system in Europe. He advanced innovations in casting type based on a matrix and hand mould, adaptations to the screw-press, the use of an oil-based ink, and the creation of a softer and more absorbent paper. Gutenberg was the first to create his type pieces from an alloy of lead, tin, antimony, copper and bismuth – the same components still used today.[18] Johannes Gutenberg started work on his printing press around 1436, in partnership with Andreas Dritzehen – whom he had previously instructed in gem-cutting – and Andreas Heilmann, the owner of a paper mill.

Compared to woodblock printing, movable type page setting and printing using a press was faster and more durable. Also, the metal type pieces were sturdier and the lettering more uniform, leading to typography and fonts. The high quality and relatively low price of the Gutenberg Bible (1455) established the superiority of movable type for Western languages. The printing press rapidly spread across Europe, leading up to the Renaissance, and later all around the world.

Page-setting room - c. 1920

Gutenberg's innovations in movable type printing have been called the most important invention of the second millennium.

Rotary printing press

The rotary printing press was invented by Richard March Hoe in 1843. It uses impressions curved around a cylinder to print on long continuous rolls of paper or other substrates. Rotary drum printing was later significantly improved by William Bullock.

Conventional printing technology

All printing process are concerned with two kinds of areas on the final output:

Image Area (printing areas)

Non-image Area (non-printing areas)

After the information has been prepared for production (the prepress step), each printing process has definitive means of separating the image from the non-image areas.

Conventional printing has four types of process:

Planographics, in which the printing and non-printing areas are on the same plane surface and the difference between them is maintained chemically or by physical properties, the examples are: offset lithography, collotype, and screenless printing.

Relief, in which the printing areas are on a plane surface and the non printing areas are below the surface, examples: flexography and letterpress.

Intaglio, in which the non-printing areas are on a plane surface and the printing area are etched or engraved below the surface, examples: steel die engraving, gravure Porous, in which the printing areas are on fine mesh screens through which ink can penetrate, and the non-printing areas are a stencil over the screen to block the flow of ink in those areas, examples: screen printing, stencil duplicator.

Letterpress

Miehle press printing Le Samedi journal. Montreal, 1939.

Letterpress printing is a technique of relief printing. A worker composes and locks movable type into the bed of a press, inks it, and presses paper against it to transfer the ink from the type which creates an impression on the paper.

Letterpress printing was the normal form of printing text from its invention by Johannes Gutenberg in the mid-15th century and remained in wide use for books and other uses until the second half of the 20th century, when offset printing was developed. More recently, letterpress printing has seen a revival in an artisanal form.

Offset

Offset printing is a widely used printing technique. Offset printing is where the inked image is transferred (or "offset") from a plate to a rubber blanket. An offset transfer moves the image to the printing surface. When used in combination with the lithographic process, a process based on the repulsion of oil and water; the offset technique employs a flat (planographic) image carrier. So, the image to be printed obtains ink from ink rollers, while the non-printing area attracts a film of water, keeping the non-printing areas ink-free.

Currently, most books and newspapers are printed using the technique of offset lithography.

Gravure

Gravure printing is an intaglio printing technique, where the image being printed is made up of small depressions in the surface of the printing plate. The cells are filled with ink, and the excess is scraped off the surface with a doctor blade. Then a rubber-covered roller presses paper onto the surface of the plate and into contact with the ink in the cells. The printing cylinders are usually made from copper plated steel, which is subsequently chromed, and may be produced by diamond engraving; etching, or laser ablation.

Gravure printing is used for long, high-quality print runs such as magazines, mail-order catalogues, packaging and printing onto fabric and wallpaper. It is also used for printing postage stamps and decorative plastic laminates, such as kitchen worktops.

Other printing techniques
The other significant printing techniques include:
Flexography, used for packaging, labels, newspapers

Dye-sublimation printer

Inkjet, used typically to print a small number of books or packaging, and also to print a variety of materials: from high quality papers simulating offset printing, to floor tiles. Inkjet is also used to apply mailing addresses to direct mail pieces

Laser printing (toner printing) mainly used in offices and for transactional printing (bills, bank documents). Laser printing is commonly used by direct mail companies to create variable data letters or coupons.

Pad printing, popular for its unusual ability to print on complex three-dimensional surfaces

Relief print, mainly used for catalogues

Screen-printing for a variety of applications ranging from T-shirts to floor tiles, and on uneven surfaces

Intaglio, used mainly for high value documents such as currencies.

Thermal printing, popular in the 1990s for fax printing. Used today for printing labels such as airline baggage tags and individual price labels in supermarket deli counters.