Matrix (printing)  In the manufacture of metal type used in letterpress printing, a matrix (from the Latin meaning "womb" or "a female breeding animal") is the mould used to cast a letter, known as a sort. Matrices for printing types were made of copper. However, in printmaking the matrix is whatever is used, with ink, to hold the image that makes up the print, whether a plate in etching and engraving or a woodblock in woodcut. In letterpress or "cold metal" typesetting, used from the beginning of printing to the late nineteenth century, the matrix of one letter is inserted into the bottom of a hand mould, the mould is locked and molten type metal is poured into a straight-sided vertical cavity above the matrix. When the metal has cooled and solidified the mould is unlocked and the newly cast metal sort is removed. The matrix can then be reused to produce more copies of the sort. The sorts could then be cleaned up and sent to the printer. Matrices could be used for many castings of type. In the hot metal typesetting systems of the later years of metal type printing, from the late nineteenth century onwards, new type is cast for each job under the control of a keyboard. The matrix or mats for a complete font are loaded into a matrix-case and inserted into a casting machine, which casts the required sorts for a page composition automatically, often from a paper reel. The standard method to make a matrix was to drive a steel punch in the shape of the type to be made into soft copper. The matrix would then be cleaned up and cut down to the width of the letter to be cast. Large typefaces, or wide designs such as emblems or medallions, were never very easily produced by punching since it was hard to drive large punches evenly. Early alternative methods used included printing from woodblocks, 'dabbing', where wood-blocks were punched into metal softened by heating, or carefully casting type or matrices in moulds made of softer materials than copper such as sand, clay, or punched lead. One solution to the problem in the early nineteenth century was William Caslon IV's riveted "Sanspareil" matrices formed by cut-out from layered sheets. The problem was ultimately solved in the mid-nineteenth century by new technologies, electrotyping and pantograph engraving, the latter both for wood type and then for matrices. From the nineteenth century additional technologies arrived to make matrices.