Sorting the Typographic 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”):

Virgule:

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 computer-based (and web) typography. Several slashes are defined in Unicode but there does not seem to be any standard for their use, and even their names conflict with those of traditional typographic characters.

The keyboard slash ( / ) is the Unicode solidus (U+002F). There are two additional Unicode slashes – division slash (U+2215) and fraction slash (U+2044) – 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 14. (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

This is a level fraction built with a keyboard 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 172 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.

In short, after analyzing and integrating all of the aforementioned sources, modern usage should be as follows:

Terminology Translated:

Usage:

This will allow the use of traditional typographic terminology, while eliminating the clutter of unnecessary characters and their attendant descriptions, to provide consistent results.