Printing Measures
The measurements used in the English-speaking printing industies were based on the imperial inch. The inch was divided by 72 points or by 6 picas or more usually in Britain, 6 Ems. The Line was also this length.
So 6 lines or 72 points both equal one inch.
Wood type is traditionally measured in lines. Metal type is usually measured in points. The measurement in either lines or points refers to the height of the letter itself in the printer's cabinet (not necessarily the height of the letter when printed).European (i.e. continental) printing houses used the Didot measure. The nearest the two systems met was when Monotype marketed some of its typefaces in Didot measures, but on a points-based body.
The following table lists some common printing measures and their equivalents in imperial and metric.
| Term | In Points | In Lines | In Imperial | In metric | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Point | 1 | 1/12th of a line | One 72nd of an inch | 0.353mm | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Pica or 'Em' or Line | 12 | 1 | 1/6th of an inch | 4.23mm | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 6-Line | 72 | 6 | 1" | 25.4mm | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 8-Line | 96 | 8 | 1.33" | 30.48mm | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 10-Line | 120 | 10 | 1.66" | 35.56mm | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 12-Line | 144 | 12 | 2" | 50.8mm | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| ... Etc ... | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
As wood type is generally bigger than metal type, it makes sense to measure it using lines. Metal type is usually measured by its height in points. Anything less than an imperial inch will be measured in points, whereas anything above that will be measured in the Pica/Em/Line measure.
