Most desktop publishing software, coming from the US, such as PageMaker and QuarkXPress and Adobe InDesign, uses the PostScript point as the unit of measurement for typography. PostScript points are defined as 1/72 of an inch, which is 0.3527777778 millimetres in SI. In the push towards metrication of all standards throughout the world, a metric standard has been devised for typography.
DIN 16507-2
DIN, the German standards body, has devised a standard way of specifying font dimensions in metric units using two values: font size (Schriftgröße) and font height (Oberhöhe). The latter is the height of a full-height letter, such as H, and the former is, by default, 72% of it (rounded) for well-proportioned, one-line leading. Font dimensions are specified in two numbers separated by a solidus: SG/OH, both in millimetres. For example, a text in about 12pt size and with default, one-line leading is defined as 4.3/6.0 according to the standard. The same size with extra leading, for one and a half lines of space, is defined as 4.3/9.0. Text in about 14pt size and default leading is 5.0/7.0.
The German standard can already be used today in web design in CSS rules, for example:
-
body { font: 4.3mm/6.0mm "Times New Roman", times, serif; }
or
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h1 { font-size: 8.6mm; line-height: 12.0mm; }
Other proposals
The DIN standard uses the H-height for the second value, but some typographers have proposed using the x-height instead.
Device resolutions in metric
Computer screens and office printers usually denote resolution in dots per inch (dpi), but phototypesetters have long used micrometres (μm). To convert dpi resolution to μm resolution, the formula to be used is:
where R is the resolution in dpi. So for example 76dpi translates to a resolution of 334.21 μm.
The CSS3 media queries standard uses a unit dpcm (dots per a centimetre) for resolution.
External links
