Blog Entry For 31/8/2013
em is for M
Today I stumbled across an article on boingboing.net that struck a chord with me for several reasons. It shows the wonderful video you see here explaining Linotype, with a fetching introductory backing of Vivaldi's Four Seasons that immediately gets my sincere nod of approval. To backtrack, for the last two days I have been working on the back-end of the Teddy Bear Club Nursery website, adding some admin code and tweaking some CSS as I go. Interestingly, have you wondered about the 'em' unit measurement in CSS? Nope? Neither have I until now. It seems its heritage lies with Linotype, when text sizes were measured in terms of the width of the letter 'M' within a given typeface. Hence the rather onomatopeic unit of measurement, which has stuck even to this day!
So, what was Linotype? There's a wonderful Wikipedia article that explains the background well. Linotype machines were used to create printed text up until around the 1970's. My father operated one for the Tweed News in Canada when he worked there in the late 60's and early 70's, and still sports a scar on his forehead to this day as a result! From a keyboard, lines of text for publication were typed in sequence. The machine drew letters from a large overhead cassette assembly and, whilst the operator began on the next line, whisks away a line of letters, known as a matrice, to be processed.
Each line, or matrice, was taken to be cast in a lead/antimony/tin alloy to form a solid block of text. For justification, the maximum line length was mechanically set. Prior to casting, each space within the line was filled with a wedged metal block. By forcing these upward, the line was pushed out until it filled the physically set line width. The matrice, along with wedged spaces, was then pressed against a molding plate to have the hot, melted alloy injected into the line. The resulting metal was automatically trimmed and ejected into a tray in sequence ready for the next line. The individual letters in the matrice are subsequently transported back up to the top of the machine via an ingenious mechanism ready to be used again. When all the text has been typed, the operator is left with a tray of lead cast text lines ready to be inserted into the press for printing.
Although a long video, technical geeks like myself will be amazed. The mechanical complexity, intricacy and beauty of this machine is simply inspiring. So, the next time you print off a document, spare a thought for the technological ingenuity of yesterday that paved the way for you.8/31/2013 Tags: em linotype printing technology