table with an accurately flat steel surface) to the manual proof press where it was hand inked and a single very high quality proof was pulled. This proof could then be photographed and converted to a negative. Black paper was inserted before the proof was photographed for each of the photos on the final page to create clear windows in the negative. The separately made halftones would be taped into these clear windows on the negative. This negative could then be used to expose the photosensitized printing plate for an offset press. In this way the heavy investment in hot metal typesetting could be adapted to the newer offset technology during a transition period. Another synergy and transition mechanism was using paper tapes made for TTS systems (linotype) and monotype tapes directly by the photo typesetter system. These tapes could be read and processed by many, maybe most optical setting systems. This allows avoiding actual use of metal, while preserving some of the value and investment in the "typesetting" and communication side of hot-metal. Such systems were widely used in the later years of hot metal, and optical typesetting systems kept supporting and further developing TTS standard, alongside similar systems for most of the optical typesetting era. Comparison to successors The nature of text printed via the hot-metal method is notably different from that produced by the phototypesetting processes that followed it. As the lead type used to print (letterpress) a page had been directly formed from the type matrix, a good fidelity to the original was achieved. Phototypesetting suffered (at least in its early days) from many problems relating to optical distortion and misalignment. These disappointing results were a thorn in the sides of many authors and readers (especially of complex or mathematical texts that had many small sub- and superscripts). A desire to re-create the aesthetic qualities of hot lead spurred Donald Knuth to create one of the first general-purpose digital typesetting programs, TeX. Although not technically typesetting, stereotyping (electrotype or nickeltype) could be used to cast a reproduction of an entire typeset page (or pages imposed in a forme) using a mold made with an impression using flong (similar to papier-mâché). The ensuing casting could be made curved for use on a rotary press or flat for the slower flat bed presses. This technique was often used in newspaper production. References External links British Printing Society Linotype