How to Finesse a Fraction
Fraction Redux
A question that comes up now and again is how to type fractions when you have a font that doesn't include that particular fraction. Many fonts contain characters for some common fractions (also known as vulgar fractions) such as: ¼, ½, and ¾. Some fonts may include even more common fractions such as ⅛, ⅝, ⅝, and ⅞. But what do you do when you want to type fractions like 4/16 or 7/9? How do you typeset a uniform set of fractions when your font doesn't contain all the fractions you need?
Pictured: top: ready-made fraction, unformatted fraction, bottom: ready-made fraction, built-up fraction, built-up fraction
Graphic © J. James
First, let's explore the terminology of fractions as used in digital fonts and typesetting:
- diagonal fraction: uses a diagonal bar to separate the numerator and denominator
- inline fraction: another name for diagonal fractions
- horizontal fraction: has a horizontal bar separating the numerator and denominator which sit directly above and below the bar
- ready-made fraction: those fractions (diagonal or horizontal) that are included as individual characters in a font
- single keystroke fraction: another name for ready-made fractions
- built-up fraction: fractions constructed on-the-fly within graphics or page layout software to look like ready-made fractions by using subscript and superscript characters, and slashes or bars
- case fraction: another name for horizontal fractions; in digital typesetting, sometimes used to also refer to ready-made diagonal fractions
- real fraction: another name for horizontal fractions; also sometimes used to refer to ready-made fractions or built-up fractions made from using properly sized superior and inferior numerals rather than manually resized characters
- solidus: a forward slash, sometimes used as the diagonal bar in a fraction
- fraction slash: the diagonal bar in a diagonal fraction; in some fonts the fraction slash, which may be known as the division slash, is a separate character from the forward slash or solidus found on most keyboards; typically the special fraction or division slash is slightly more angled and a touch thinner than the solidus
Although you could use an expert character set or math font that contains a wide variety of ready-made fractions (as well as individual superior and inferior numerals already sized and spaced to construct any fraction), many designers simply create their own fractions in their graphics or page layout software as needed. Known as built-up fractions, this works fine if you don't need to typeset dozens or hundreds of fractions regularly. While the specific commands may differ from one program to the next, follow these general instructions to create your own typographically correct inline, diagonal fractions.
Note also that in written English fractions take full-size, i.e. 1/2, 3/4, etc…and ditto for the “th” or “rd” in dates (i.e. 3rd, 4th). The only time you use the smaller script (that dang MS Word defaults to!) is in written math.
For your Step 2, italicizing the slash (also called a virgule) often helps the figure appear more similar to the ready-made fractions. (Hinted at but not stated in your step.)
I also decrease the character spacing (usu. by -0.02 to -0.03) to match a specific font appearance.
Since making the numerator and denominator smaller usually makes them appear as if they were set in the light version of a font, I frequently set these two elements as bold to compensate for the apparent discrepancy in weight. Much depends on the font being used as well as the size.