This is a very interesting a helpful set of articles on the correct use of typography, something that I often took for granted, and only now realise how wrong the things I have been shown have been.
It also has a little detail on Typography over the correct use of punctuation.
Use Dashes Dashingly
Most fonts are equipped with at least two dashes: an en dash (–,
–, which is the width of a lowercase “n”) and an em dash (—,
—, which is the width of a lowercase “m”). Don’t confuse these with the hyphen (-), which isn’t a dash at all but a punctuation mark.
En Dash (–)
En Dash gets its name from its length. It is one ‘N’ long (En is a typographical unit that is almost as wide as ‘N’). En Dash is used to express a range of values or a distance:
People of age 55–80 are more prone to hypertension.
Delhi–Sidney flight was late by three hours.
In MS Word, you can put an En Dash either from the menu, clicking Insert->Symbol or by the key-combination, Ctrl + Num –. The ASCII code for En dash is “–”.
In expressing game scores, En Dash is used.
India beat Pakistan 250–190.
Use En Dash in compound adjectives in which the two participant terms themselves are compound.
Hyper-threaded–land-grid-array processor powers my PC.
Em Dash (—)
Em Dash gets its name from the width of it, which is roughly one ‘M’ long or two ‘N’ long (Em is a typographical unit twice the length of en—and almost the length of capital ‘M’). The Em Dash can be typed as two En Dashes. Alternatively, in MS Word, you can type two hyphens together to get an Em Dash. The ASCII code for this is “—”.
Em Dash is used to set off parenthetical elements, which are abrupt. This is different from commas separating parenthetical elements. For instance:
The tea—with cardamom and other spices—was delicious and fragrant.
Make sure you don’t use spaces around the Em Dash.
Em Dash also separates the final part of a sentence that is logically not part of the sentence.
Several friends were present—Saurabh, Arun, and Smija, among them.
Though most people prefer to follow the Em Dash without spaces, some people recommend using Em dash or En Dash with spaces around.
Hyphens and dashes are confused to the point that they are now used almost interchangeably by some. Some fonts, such as Adobe Garamond Pro, retain hyphens in their original form; those hyphens look more like the diagonal stroke of a calligrapher’s pen than a straight horizontal line. You’ll also often see hyphens used as a replacement for a minus sign; however, a longer character is available in some fonts for this purpose.
Although the hyphen does look quite a bit like a dash or minus sign, it is a punctuation mark. It should be used primarily to hyphenate words in justified type. On the Web, this isn’t much of a concern because, as mentioned, there is no standard hyphenation control in browsers. The hyphen should also be used in compound modifiers (such as “fine-tuned”), to join digits in phone numbers, and in a few other rare cases.
The En Dash and the Em Dash
In The Elements of Typographic Style – which is the unofficial bible of the modern typographer – Robert Bringhurst recommends that dashes in text should be the en dash flanked by two spaces. This is much less visually disruptive than using the em dash with no space—which is recommended in editorial style books such as The Chicago Manual of Style — because there is less tension between the dash and the characters on either side of it.
Why go against The Chicago Manual of Style in this case? The reason is that style manuals are concerned mostly with punctuation, not typography. An en dash surrounded by spaces achieves the same effect as an em dash with no spaces, but typographically it is less disruptive.
The practice of using two hyphens for a dash is a holdover from the days of typewriters. Besides being visually disruptive to smooth blocks of text, it is now unnecessary with the richer character sets that are available to typographers.
The en dash is also used to indicate ranges of numbers (such as “7–10 days”), although it isn’t flanked by spaces in this case.
Special ALT Characters
Alt 0145 ‘
Alt 0146 ’
Alt 0147 “
Alt 0148 ”
Alt 0150 – (en dash
Alt 0151 — (em dash