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Rotogravure (or gravure for short) is a type of intaglio printing process, which involves engraving the image onto an image carrier. In gravure printing, the image is engraved onto a cylinder because, like offset printing and flexography , it uses a rotary printing press .
Photogravure is distinguished from rotogravure in that photogravure uses a flat copper plate etched rather deeply and printed by hand, while in rotogravure, as the name implies, a rotary cylinder is only lightly etched, and it is a factory printing process for newspapers, magazines, and packaging.
In intaglio printing, the lines to be printed are cut into a metal (e.g. copper) plate by means either of a cutting tool called a burin, held in the hand – in which case the process is called engraving; or through the corrosive action of acid – in which case the process is known as etching.
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 known for its ability to produce high-quality, high-resolution images with accurate color reproduction and using viscosity control equipment during production.
Offset printing is a common printing technique in which the inked image is transferred (or "offset") from a plate to a rubber blanket and 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.
Early rotary newspaper printing press in Bristol, 1858. William Nicholson filed a 1790 patent for a rotary press. The rotary press itself is an evolution of the cylinder press, also patented by William Nicholson, invented by Beaucher of France in the 1780s and by Friedrich Koenig in the early 19th century.
[1] Machine components such as the print cylinder, doctor blade assembly, printing plates, stress/friction and more, affect the registration of the machine. [2] Inconsistencies among these components can cause the printing press to fall out of registration; that is when press operators will begin to see defects in their print.
Thinner traps are less visible. Therefore, the trap width is set to a strict minimum, dictated by the maximum amount of misregistration of the entire workflow up to the press. When printing at 150 lpi, traps are usually between 1/150 and 1/300 inch (0.48 pt and 0.24 pt, 0.16 mm and 0.08 mm). These values are usually multiplied by 1.5 or 2 when ...