Relief print in the context of "Matrix (printing)"

Intaglio (/ɪnˈtæli.oʊ, -ˈtɑːli-/ in-TAL-ee-oh, -⁠TAH-lee-; Italian: [inˈtaʎʎo]) is the group of printing and printmaking techniques in which an image is incised into a surface and the incised line or sunken area holds the ink. It is the direct opposite of a relief print where the parts of the matrix that make the image stand above the main surface.

Normally copper, or in recent times zinc, sheets called plates are used as a surface or matrix, and the incisions are created by etching, engraving, drypoint, aquatint or mezzotint, often in combination. Collagraphs may also be printed as intaglio plates.

Planographic printing means printing from a flat surface, as opposed to a raised surface (as with relief printing) or incised surface (as with intaglio printing). Lithography and offset lithography are planographic processes that rely on the property that water will not mix with oil. The image is created by applying a tusche (greasy substance) to a plate or stone. The term lithography comes from litho, for stone, and -graph to draw. Certain parts of the semi-absorbent surface being printed on can be made receptive to ink while others (the blank parts) reject it.

Chromolithography is a method for making multi-colour prints in lithography, and in theory includes all types of lithography that are printed in colour. However, in modern usage it is normally restricted to 19th-century works, and the higher quality examples from that period; almost all 21st-century colour printing uses lithography, but would not be described using the term chromolithography. When chromolithography is used to reproduce photographs, the term photochrome is frequently used. Lithography is a method of printing on flat surfaces using a flat printing plate instead of raised relief or recessed intaglio techniques.

Chromolithography became the most successful of several methods of colour printing developed in 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 different colours. Hand-colouring also remained important. For example, elements of the official British Ordnance Survey maps were coloured by hand by boys until 1875. The initial chromolithographic technique involved the use of multiple lithographic stones, one for each colour, and was still extremely expensive when done for the best quality results. Depending on the number of colours present, a chromolithograph could take even very skilled workers months to produce.