Sabon was developed in the early 1960s for a group of German printers who sought a "harmonized" or uniform font that would look the same whether set by hand or on a Monotype or Linotype hot metal typesetting machine. They were quite specific about the sort of font that might fit the bill, rejecting the modern and fashionable in favour of solid 16th century tradition - something modelled on the work sixteenth-century engravers Claude Garamond and Robert Granjon. The requirement that all weights have the same width was influenced by the 'duplex' system of lead casting on the Linotype system: each Linotype-matrix can cast two different characters: roman or italic, roman or bold, which must have the same width. It also meant that the typeface then only required one set of copyfitting data (rather than three) when compositors had to estimate the length of a text prior to actual typesetting (a common practice before computer-assisted typesetting). Another hint of the design's origins in hot-metal typesetting technology is the narrow 'f', since Linotype machines cannot cast an 'f' that kerns, or extends beyond the letter's body.