Bembo's development took place following a series of breakthroughs in printing technology which had occurred over the last fifty years without breaking from the use of metal type. Pantograph engraving had allowed punches to be precisely machined from large plan drawings. This gave a cleaner result than historic typefaces whose master punches had been hand-carved out of steel at the exact size of the desired letter. It also allowed rapid development of a large range of sizes. In addition, hand printing had been superseded by the hot metal typesetting systems of the period, of which Monotype's was one of the most popular (in competition with that of Linotype's). Both allowed metal type to be quickly cast under the control of a keyboard, eliminating the need to manually cast metal type and slot it into place into a printing press. With no need to keep type in stock, just the matrices used to cast the type, printers could use a wider range of fonts and there was increasing demand for varied typefaces. Artistically, meanwhile, the preference for using mechanical, geometric Didone and “modernised old style” fonts introduced in the nineteenth century was being displaced by a revival of interest in "true old style" serif fonts developed before this, a change that has proved to be lasting. At the same time, hot metal typesetting had imposed new restrictions: in Monotype's system (while less restrictive than Linotype's), in order to mechanically count the number of characters that could be fitted on a line, letters could only be certain widths, and care was needed to produce letters that looked harmonious in spite of this.