August 3rd, 2016 by Ilene Strizver
Hyphens, en and em dashes appear with great frequency in typeset copy. Unlike the days of typewriters where the only character available to represent these three punctuation marks was a hyphen, all three are available in today’s fonts. They all have different usages, as well as varying design characteristics for each typeface design.
In today’s digital world where graphic designers are responsible for so many aspects of typesetting and production, it is up to us to know the difference between these three symbols, and to check for appropriate usage and appearance in every job we come into contact with. From reviewing the initial copy (text) to proofreading the final output, designers need to be aware of these punctuation marks, and edit typeset copy accordingly for typographic accuracy as well as good taste.
When to Use Hyphens, En and Em Dashes in a Sentence
Hyphens ( – ) are the shortest of the three, and are used to hyphenate words at the end of line. They are also used for compound, or hyphenated words and phrases, such as sister-in-law and merry-go-round. In addition, they are the correct punctuation for phone numbers, as well as game and sport scores, and contest results.
En dashes ( – ) are the middle width of the three, and are used to indicate a break in time, or a span or range. (An easy way to know if an en dash is the correct punctuation for a range is if it can be replaced with a preposition, such as to or through.) They are also used to indicate a connection or contrast between pairs of words, such as an east–west flight, and a Democrat–Republican split. The en dash is probably the least understood and most incorrectly used of the three; it is often substituted with either a hyphen or an em dash, both of which are wrong when the en dash is the correct punctuation.
Em dashes ( — ) are the widest of the three. They are most often used for a break in thought, or a thought within a thought or a sentence.
While hyphens are usually consistent in their design relative to each typeface (usually short horizontal or slightly angled strokes), en and em dashes can vary greatly from typeface to typeface. They can differ both in the width of the actual glyph, as well their overall spacing, that is, the space added (or not added) to both sides of the glyph to give them ‘breathing room’ when they appear next to other characters.
The historical standards in the days of metal type for the width of both dashes were fixed for each point size, that being 1000 units to the em square, while en dashes were half that, at 500 units to the em dash. (An em is a measurement relative to the point size of the type, therefore in a 12-point typeface an em is 12 points.)
In addition, dashes had little or no additional space on both sides (referred to as side-bearings in the world of type design). Today’s specs are not that rigid, and can (and should in my opinion) vary dependent on the overall width of the typeface design.
A good rule of thumb is for en dashes to approximate the width of the cap or lowercase ‘n’, while the em dash to approximate the cap or lowercase ‘m’. This results in dashes that are in proportion to the typeface they are designed for: dashes in condensed or compressed typestyles will be narrower, while regular or expanded typefaces will have dashes that are wider, and in proportion to their width.
In addition, dashes should have some space surrounding them so they aren’t crowded and don’t appear to crash into other characters.
So how does the type-sensitive designer deal with em dashes that look too wide in any particular typeface? And what about either dash that appears too tight? It is an accepted practice by many designers to substitute an en dash for a very wide em dash.
While this might not be ‘grammatically correct’ according to grammar references and style manuals, it is a typographic practice that takes into account the varying widths of dashes from typeface to typeface, and serves to eliminate the visual holes that a very wide em dash can create.
As for any dash that appears too tight, space can be added to the right and left to give them a more open appearance. This can be achieved via kerning, or with the use of thin spaces if you are using InDesign. Keep in mind that this should be done on a case-by-case basis, and done consistently for any particular typeface, project, web site or client.
Final Thoughts On How To Use Hyphens In Writing
Never use two hyphens in place of a dash in professional typography. This is a holdover from the typewriter days when the limited keyboard did not include dashes, thus two hyphens were used in place of dashes.
The problem arises today because many copywriters continue to use this outdated practice, and submit copy with double hyphens that are not corrected by designers and webmasters. The best way to avoid this is to proofread and correct all copy before it is typeset.
In addition, when setting type for the web or other digital media, always try to adhere to professional standards of typesetting, including the correct usage of en and em dashes. While there are some instances where this is not possible (such as some email clients which do not support the use of dashes), in most cases it is.
Some instances might require special HTML coding, so be sure to inform all those responsible for the type styling, including webmasters and developers who might not be aware of the correct typographic practices.