science

Metric typographic units

Metric typographic units is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Metric typographic units rather than just read about it. In short: Metric typographic units have been devised and proposed several times to overcome the various traditional point systems. After the French Revolution of 1789 one popular proponent of a switch to metric was Didot, who had been able to standardise the continental European typographic measurement a few decades earlier.

Key takeaways

Metric typographic units belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Metric typographic units to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Metric typographic units from memory before moving on to harder problems.

Reference excerpt

Metric typographic units have been devised and proposed several times to overcome the various traditional point systems. After the French Revolution of 1789 one popular proponent of a switch to metric was Didot, who had been able to standardise the continental European typographic measurement a few decades earlier. The conversion did not happen, though. The Didot point was metrically redefined as 1⁄2660 m (≈ 0.376 mm) in 1879 by Berthold. The advent and success of desktop publishing (DTP) software and word processors for office use, coming mostly from the non-metric United States, side stepped this metrication process in typography. DTP commonly uses the PostScript point, which is defined as 1⁄72 of an inch (0.3527 mm).

Metric Didot Point

With the introduction of phototypesetting in the 1970s metric units were increasingly used in typography. The Didot point was redefined once again to 375 μm, exactly 3⁄8 mm.

Quart

Also in the 1970s, the new unit quart (quarter millimetre, abbreviated 'q') of 250 μm (1⁄4 mm) was devised. The German draft standard DIN 16507-2 has suggested that digital typography will be specified using millimeters, with sizes in multiples of 0.250 mm. In some special cases where finer resolution is required, it is permitted with sizes in multiples of 0.100 or 0.050 mm (respectively 2.5 and 5 times finer step sizes). German graphic designer and typographer Otl Aicher (1922 – 1991) vividly encouraged the use of the quart, and provided a suggested list of common sizes:

Note that Aicher's font sizes are based on the DIN standard then in development, which uses the H-height, whereas in lead typesetting the larger cap height was used. Some typographers have proposed using the x-height instead, because the physiological size depends more on the size of default, lowercase letters.

Device resolutions The resolution of computer screens is often denoted in millimetres pitch, whereas office printers are usually denoted reciprocally in dots per inch ('dpi', 'd/in'). Phototypesetters have long used micrometres. To convert dpi resolution to μm resolution, the formula to be used is 25400⁄R, where R is the resolution in dpi. So for example 96 dpi translates to a resolution of 265 μm. The CSS3 media queries draft introduces the unit dots per centimetre (dpcm) for resolution.

See also Typographic unit Dots per centimeter, a metric unit of dot density in printing, video or images, proposed to replace dots per inch (DPI). Pixels per centimeter, a metric unit of pixel density proposed to replace pixels per inch (PPI). Himetric, a resolution independent, digital, metric, measurement unit

References

External links Metric typographic units Typographic measurement

Illustrations

Worked examples

Example 1 — a first encounter with Metric typographic units

Start with the simplest possible case. Write down what Metric typographic units claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Metric typographic units before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Metric typographic units ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Metric typographic units

In research: Metric typographic units appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Metric typographic units in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Metric typographic units is common in secondary-school and first-year university syllabi. It links to neighbouring topics Typography, Units of length, so understanding it makes those chapters shorter.
In everyday life: Look for Metric typographic units outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Metric typographic units in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Metric typographic units means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Metric typographic units out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Metric typographic units in simple terms?

Why does Metric typographic units matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Metric typographic units?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Metric typographic units.