“House style” is a publishing term defining the set of rules used in the production of whatever it is they publish. It’s all about consistency – not only within a single work, but across the entire catalogue of the press – everything from spelling conventions to punctuation and layout.

Proper typesetting of punctuation is as meaningful and important as proper spelling. Each character performs a specific task and is not interchangeable, even though they may look similar, as in ’ ′ ´ (apostrophe, prime, and acute). It is important to remember that individual punctuation marks can have a completely different look from one typeface to another – including looking like other characters in different typefaces – which is why font selection is important. You would no more use a zero in place of an alphabetic “oh” simply because of the way it looks, and since (X)HTML characters can be specified by name, it is critical to understand that usage and set punctuation marks accordingly.

Visual Index of Punctuation & Figures:

Single Stroke:

The Slash Hassle:

Typographically, there are two slash characters: the solidus and the virgule. (The backslash found on computer keyboards has no typographic analogue or function.) Per Bringhurst, they are traditionally used as follows:

Solidus (aka “fraction bar”):

• used with superior and inferior numbers to create ad hoc fractions (where the numerator is set above the baseline)
• in the abbreviation of British imperial currency, prior to 1971.

Virgule:

• to create level fractions
• by Medieval scribes and later writers as a form of comma (virgule being French for “comma”)
• to represent a line break when verse is set as prose
• as a sign of separation when writing dates, addresses, and such.

Visually, the solidus is slanted more heavily to the right, which results in greater separation between the adjoining characters, as well as being kerned so that the character immediately following tucks deeper under the terminating edge.

While this may seem straightforward (because, face it, it is), things get confusing when you move to the ever-dicey arena of web typography. Several slashes are defined in Unicode character sets, but there does not seem to be any standard for their use, and even their names conflict with traditional typographic names.

The keyboard slash ( / ) is equivalent to the Unicode SOLIDUS (U+002F) ( / ). There are two additional Unicode slashes – DIVISION SLASH (U+2215 or ∕) and FRACTION SLASH (U+2044 or ⁄) – which appear to render identically in many fonts – ∕ ⁄ – and are kerned to allow trailing figures to be positioned before the slash appears to end. Thus, you can create a fraction ¹⁄₄. (Note that super- and subscript was used to more properly orient the characters vertically.)

This is a level fraction built with a division slash: 1∕4.

This is a level fraction built with a fraction slash: 1⁄4.

And so, extrapolating on Bringhurst, usage here is to build uneven fractions with the Unicode FRACTION SLASH (in place of the typographic solidus) in conjunction with super- and subscripted characters, and to use the keyboard slash (what Unicode refers to as “solidus”) as the typographic virgule.

The use of the slash in the formatting of currency has its own fascinating history. In A.D. 309, Constantine I introduced the gold coin known as the solidus. It was standardized as ¹⁄₇₂ of the Roman pound, the libra, and was different than an earlier so-named coin, introduced by Diocletian. There were 25 silver denarii to the solidus.

Some centuries later, British imperial currency was abbreviated following the Libra-solidus-denarius progression (L/s/d) of the Romans: £ for the pound sterling, s. and d. for the shilling and pence (hence £/s/d). Bringhurst suggests that while these abbreviations are traditionally written using the solidus figure (from which the typographic name derives), the “design and fitting of the characters on most modern type fonts” make it more appropriate to use an italic virgule (herein an italic keyboard slash) to set references to pre-decimalization British currency. Otherwise, you get this: £⁄s⁄d.

Double Stroke:

Miscellaneous:

Positioning:

Notes:

Bringhurst, Robert. Elements of Typographic Style, The. 2nd ed. (Vancouver: Hartley & Marks, Publishers, 2002).