After a two month break, Metric Views returns with an article by UKMA’s new Chairman, John Frewen-Lord, about an aspect current metric usage. (With apologies to Mark Twain for the headline).
The modern Système Internationale (SI) is supposed to be language-independent i.e. metric measurement unit symbols appear the same no matter the language of the country in which they are used. It is therefore interesting to note that the so-called ‘micron’ – an obsolete unit deprecated in SI – appears to be alive and well, and its death obviously greatly exaggerated.
The micron is of course a ‘slang’ term for the micrometre – symbol µm – and equal to 1/1000th of a millimetre. Yet the term ‘micron’ refuses to die. It keeps cropping up in all sorts of situations – some at the industrial level, and some at the ‘retail’ level. The problem with using the term ‘micron’ (as opposed to micrometre) is that the symbol µm does not seem to be directly related to it, even though the micrometre and the micron are the exact same unit (in fact, the use of the µ by itself is often used to mean the micron). Consequently, whenever the term ‘micron’ is used, it usually has to be spelt out in full – the very antithesis of what SI is about.
Because most metric units (including the micron) very often have different spellings in different languages (which the use of the standard language-independent SI symbols is designed to obviate), it means that whenever it is used in specifications, product descriptions, instruction manuals and the like, it has to be spelt out for each language. Very different spellings can be encountered for the micron in everything from specified coating thicknesses used in industrial processes to ultra-thin sheeting used in the construction industry as well as all sorts of manufactured products.
One product encountered at the retail level, seen in a specialist printer’s supply shop, is a particular brand of A4 laminated sheet pouches (manufactured in Eastern Europe). While the length and width are specified using the correct mm symbol, the thickness is spelt out using the term ‘micron’ – in fourteen Western and Eastern European languages! Thus the packaging shows the pouch size as 303 mm x 216 mm (to fit an A4 sheet), with the thickness shown as follows:
English – 75 Micron
French – 75 micron
German – 75 Mikron
Spanish – 75 micrón
Italian – 75 micron
Portuguese – 75 mícron
Swedish – 75 mikron
Norwegian – 75 Mikrometer (the correct term for a µm)
Finnish – 75 mikroni
Polish – 75 mikronów
Czech – 75 mikron
Hungarian – 75 mikron
Slovakian – 75 mikrónov
Turkish – 75 mikron
It seems such a waste of space on the packaging for all these different versions of the word ‘micron’ to be printed out, not to mention the time it must have taken someone to look up all the translations. Why can’t the proper term ‘micrometre’ and its symbol µm be used in all cases?
The pouch size then could be simply shown – just the once – as 303 mm x 216 mm x 75 µm. Metric units used as they should be.