The Gravure process is a type of intaglio process in which the actual image is etched into the surface of a plate or metal cylinder. The image consists of tiny cells (or wells) engraved into the cylinder; there may be as many as 22,500 ink wells per square inch. When the cylinder is rotated in a fountain of ink, the excess ink in the non-image area is removed by a thin piece of stainless steel called a doctor blade. The size and depth of each ink well determines how much ink will be deposited on the substrate. When paper is passed between the plate cylinder and rubber impression roller, it acts like a blotter and absorbs the remaining ink in the microscopic wells.
In gravure printing there are sheetfed and webfed (rotogravure) presses. Sheetfed gravure is targeted at limited production runs of fine art prints, high quality art, photographic books, advertising leaflets, and higher denomination postage stamps. Rotogravure is targeted at larger runs of 300,000 copies or more and includes weekly or monthly magazines, mail order catalogs, specialized packaging, wallpaper, and some decorative laminates. Both presses require plate-making (or cylinder engraving) and proofing, which is often very expensive. Color corrections and last-minute changes often require cylinder retouching, and this can sometimes be slow and very time-consuming.
The print quality of photographs using gravure is often superior to other printing processes. Both press configurations are direct printing, so ink-and-water balance is not a variable for controlling image density. The inks are either petroleum-based or water-based, and the use of electrostatic assist allows for better ink transfer on substrates with hard surfaces and poor ink absorption. Gravure gives a true halftone effect where photographs tend to have greater contrast and detail due to heavy ink films and use of finer screen rulings. Because of the cell structure, fine details in type-matter and line-work are of critical concern. When using type styles containing serifs, it is advised not to use type sizes smaller than eight point. Overall, gravure is great for long runs (300,000 or more) and capable of maintaining color consistency on a wide range of substrates.