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Diagram of rotogravure process. 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.
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.
A registration mark showing a slight misalignment of the printing heads, resulting in subtle color hues visible around the edges of the black area (click image to zoom in). In printing, registration black is a black color that includes 100% of each of the process colors used.
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.
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.
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.
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.
The doctor blade is a relatively cheap and disposable consumable, while the gravure cylinder or flexo anilox is a more expensive component of the press. Typical materials for the blade are steel or polymer: [3] gravure cylinders are normally hard-chrome plated [4] and flexo aniloxes may be chromed or ceramic. [5]