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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| History of printing | 13/16 | https://en.wikipedia.org/wiki/History_of_printing | reference | science, encyclopedia | 2026-05-05T06:41:08.952923+00:00 | kb-cron |
Invented by Bavarian author Alois Senefelder in 1796, lithography is a method for printing on a smooth surface. Lithography is a printing process that uses chemical processes to create an image. For instance, the positive part of an image would be a hydrophobic chemical, while the negative image would be water. Thus, when the plate is introduced to a compatible ink and water mixture, the ink will adhere to the positive image and the water will clean the negative image. This allows for a relatively flat print plate which allows for much longer runs than the older physical methods of imaging (e.g., embossing or engraving). High-volume lithography is used today to produce posters, maps, books, newspapers, and packaging — just about any smooth, mass-produced item with print and graphics on it. Most books, indeed all types of high-volume text, are now printed using offset lithography. In offset lithography, which depends on photographic processes, flexible aluminum, polyester, mylar or paper printing plates are used in place of stone tablets. Modern printing plates have a brushed or roughened texture and are covered with a photosensitive emulsion. A photographic negative of the desired image is placed in contact with the emulsion and the plate is exposed to ultraviolet light. After development, the emulsion shows a reverse of the negative image, which is thus a duplicate of the original (positive) image. The image on the plate emulsion can also be created through direct laser imaging in a CTP (Computer-To-Plate) device called a platesetter. The positive image is the emulsion that remains after imaging. For many years, chemicals have been used to remove the non-image emulsion, but now plates are available that do not require chemical processing.
== Color printing ==
According to Michael Sullivan, the earliest known example of color printing "is a two-color frontispiece to a Buddhist sutra scroll, dated 1346". Color printing continued to be used in China throughout the Ming and Qing dynasty. Chromolithography became the most successful of several methods of colour printing developed by the 19th century; other methods were developed by printers such as Jacob Christoph Le Blon, George Baxter and Edmund Evans, and mostly relied on using several woodblocks with the colors. Hand-coloring also remained important; elements of the official British Ordnance Survey maps were colored by hand by boys until 1875. Chromolithography developed from lithography and the term covers various types of lithography that are printed in color. The initial technique involved the use of multiple lithographic stones, one for each color, and was still extremely expensive when done for the best quality results. Depending on the number of colors present, a chromolithograph could take months to produce, by very skilled workers. However much cheaper prints could be produced by simplifying both the number of colors used, and the refinement of the detail in the image. Cheaper images, like the advertisement illustrated, relied heavily on an initial black print (not always a lithograph), on which colors were then overprinted. To make an expensive reproduction print as what was once referred to as a "’chromo’", a lithographer, with a finished painting in front of him, gradually created and corrected the many stones using proofs to look as much as possible like the painting in front of him, sometimes using dozens of layers. Aloys Senefelder, the inventor of lithography, introduced the subject of colored lithography in his 1818 Vollstaendiges Lehrbuch der Steindruckerey (A Complete Course of Lithography), where he told of his plans to print using color and explained the colors he wished to be able to print someday. Although Senefelder recorded plans for chromolithography, printers in other countries, such as [France and England, were also trying to find a new way to print in color. Godefroy Engelmann of Mulhouse in France was awarded a patent on chromolithography in July 1837, but there are disputes over whether chromolithography was already in use before this date, as some sources say, pointing to areas of printing such as the production of playing cards.
== Offset press (1870s) ==
Offset printing is a widely used printing technique where the inked image is transferred (or "offset") from a plate to a rubber blanket, then to the printing surface. When used in combination with the lithographic process, which is based on the repulsion of oil and water, the offset technique employs a flat (planographic) image carrier on which 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.
== Screenprinting (1907) ==
Screenprinting has its origins in simple stencilling, most notably of the Japanese form (katazome) user who cut banana leaves and inserted ink through the design holes on textiles, mostly for clothing. This was taken up in France. The modern screenprinting process originated from patents taken out by Samuel Simon in 1907 in England. This idea was then adopted in San Francisco, California, by John Pilsworth in 1914 who used screenprinting to form multicolor prints in a subtractive mode, differing from screenprinting as it is done today.
== Flexography ==
Flexography (also called "surface printing"), often abbreviated to "flexo", is a method of printing most commonly used for packaging (labels, tape, bags, boxes, banners, and so on). A flexo print is achieved by creating a mirrored master of the required image as a 3D relief in a rubber or polymer material. A measured amount of ink is deposited upon the surface of the printing plate (or printing cylinder) using an anilox roll. The print surface then rotates, contacting the print material which transfers the ink. Originally flexo printing was basic in quality. Labels requiring high quality have generally been printed by offset printing until recently. Great advances have been made to the quality of flexo printing presses.
== Phototypesetting ==
Phototypesetting is a method of setting type which uses photography to make columns of type on a scroll of photographic paper.
== Dot matrix printer (1968) ==