Font Characteristics

A huge variety of fonts can be used on a a computer. Understanding how they work can help you use them to best effect, and possibly prevent you from using too many in your documents.

• Before creating or modifying fonts, you should check that your font utility is suitable for the technology in your computer. Fontographer, a utility for the Mac OS, can be used to modify TrueType or PostScript fonts designed for either the Mac OS or Windows.
• Different versions of a font in bitmap, TrueType or PostScript form, can have different characteristics, even though they have the same font name. Sometimes, you’ll get alternative characters, although most differences are more subtle. Unfortunately, even small variations in character spacing can mess up the way the lines wrap in a document.
• The key combinations shown in this document apply to the Mac OS. Other operating systems can use similar or entirely different combinations.

Using Different Typefaces

Most fonts are designed for a particular purpose. For example, a serif font, as shown in the examples below, is very easy to read in large blocks of text.

In contrast, a sans-serif font, as shown below, stands out in headlines and titles.

In addition, you may need special fonts for fractional characters, such as:-

or for foreign or specialised characters, as in:-

Unfortunately, in older fonts of the latter kind, there isn’t any correlation between the actual character and what you type on the keyboard. The last of the fonts illustrated above is used for the International Phonetic Alphabet (IPA), which requires a large number of strange characters.

Decorative fonts can be eye-catching, although sometimes tricky to read. Examples include:-

Finally, there are dingbat fonts that you can combine with text as an alternative to standard graphic elements. The following show a random selection of such characters:-

Characteristics and Legibility

The diagram below shows some of the basic characteristics that define a font:-

• The weighting or style, as well as line spacing, are also important.

The following diagram shows various parameters in more detail:-

Some of these dimensions are defined as follows:-

• Ascent: the maximum height of an ascender for the entire font.
• Descent: the maximum depth of a descender for the entire font.
• Leading: the space between each row of characters.
• Width: the cursor movement required to move over a character.
• Maximum kern: the largest kern possible for the entire font.
• Offset: the positioning of a character within the maximum width, measured from the beginning of the kern space.
• Maximum Width: the smallest width that all characters fit into. The left hand side is the reference for offsets. In some fonts, specific characters can exceed the maximum width, although this doesn’t usually cause any problems.

For optimum legibility a balance must be struck between the continuity of each line of text and the variations that identify each character. The most important parameters are:-

Proportion

The proportion of a font describes the ratio of its height to width. A font that has narrow letters allows you to view a line of words at a glance. However, if the characters are made too narrow each character becomes indistinct, making the text difficult to read.

Horizontal Space

The horizontal spaces between each character should be easy to see, but they shouldn’t break up the invisible ‘line’ that your eyes follow as they scan the text.

Banding

The vertical space between lines is known as banding. This leads the eye from one row to the next and is basically set by the height of a font’s lowercase letters.

Ascenders and Descenders

The ascent of a font is set by the height of the uppercase letters and its numerals. In many fonts the lowercase letters are almost as high as the uppercase characters, which, when closely placed, can make the characters difficult to read.

Those parts of uppercase letters and numerals that extend above lowercase letters and the parts of lowercase letters beneath the baseline are known as ascenders or descenders. Both must stand out clearly between lines, although he ascenders are more important, since we read down the page.

Leading

The space between the top of the uppercase letters and the bottom of the descenders from the line above is known as leading, pronounced ‘ledding’. If there’s enough banding you can increase the leading, font ascent or both. Luckily, a large ascent looks elegant and doesn’t disturb the banding.

Serifs

Characters are best defined by sharp edges. A serif font contains serifs, horizontal lines on the characters that add distinction and increase the apparent line density.

• Serifs should always align with each other in order to emphasise the line itself.

• Line density can also be increased by reducing letter width and spacing, which makes each word stand out more clearly.

A sans-serif font, such as Geneva, can be more difficult to read than a serif font, but can be useful in confined spaces, as in lists or tables. Here’s an example:-

Character Spacing

Proportional and Monospaced Fonts

In a proportional font, such as Times, each character has a different width, apart from numerals which have identical widths to ensure alignment in columns of numbers. Here’s an example:-

In a monospaced font, such as Monaco or Courier, all characters, including punctuation and spaces, are of fixed width, as on an old-fashioned typewriter, which looks like this:-

• Monospaced fonts are useful in tables but don’t look attractive in long lengths of text.

Pair Kerning

Some fonts automatically kern pairs of characters. The effect is shown below:-

In some instances you may need to apply manual kerning in order to improve the flow of text. You should apply this as follows:-

Variations in Standard Characters

Ligatures

A ligature is created by tying together two characters, as in the following:-

Ligatures are often used in place of characters that misbehave when placed next to each other. The most common character to cause problems is the letter f, particularly when followed by an i or l, since the ‘arch’ of this can collide with the next character in an unattractive manner. The problem is often solved by using the following ligatures in place of the matching character combinations:-

There are three ways of dealing with awkward character pairs:-

1. Use fonts with built-in ligatures

   This gives consistent pair kerning, although custom encoding is required with older fonts, requiring each ligature to be produced using a key combination that’s otherwise used for a standard character. You can use KeyCaps or PopChar Pro to find out what keys to press.

2. Use expert font sets

   These font contains all the necessary ligatures, but you must switch fonts to get them, although some applications can do this automatically. Unfortunately, since automatic pair kerning only works when you’re working in a single font, you may have to adjust the spacing manually.

3. Use fonts that doesn’t need ligatures

   An easy solution, although using ligatures usually gives better results.

• Some applications aren’t aware of ligatures when spell-checking, requiring you to create a document without ligatures, spell-check it and then use Find and Replace to change the necessary character groups to ligatures.

Numerals

Most fonts provide numerals, also known as lining figures. All of the numbers in a character set should have the same width and height, usually of a height matching that of an uppercase letter, and shouldn’t usually have any ascenders or descenders. Such numerals are ideal for tabular data, although they’re not always attractive in a line of text. For example, in the following line:-

the numbers dominate the text, making the whole thing rather ‘lumpy’ and slightly difficult to read. Smaller characters, as used below, can look more elegant.

There are three ways of improving the appearance of numerals within text:-

1. Reduce the size of a standard font

   Unfortunately, such numbers aren’t quite right, since they’re not designed for the job. But if you don’t have any other choice this is a partial solution to the problem.

2. Use a font with three-quarter height numerals

   These give reasonable results without introducing extra complications.

3. Use expert font sets

   These look good but you’ll need to use two fonts in your text, which means you’ll suffer from the the usual problem of kerning with different fonts.

• A Small Caps and Old-Style Figures (SC＆OSF) font expert set includes lowercase non-lining figures, often with ascenders and descenders. Unfortunately this kind of font usually lacks three of the essential f ligatures.

Small Capitals

Until recently, small caps were out of fashion. They do, however, remove much of the ‘lumpiness’ that can be introduced by modern acronyms. Consider the following statement with standard capitals:-

and compare it with the following which uses small caps:-

Small caps can also be used in titles, such as:-

You can create small caps as follows:-

1. Use smaller font sizes

   Although better than nothing, this doesn’t really give the correct proportions. Some applications can create small caps automatically, often by using this method.

2. Use expert font sets

   These gives perfect results, but introduce two fonts to the text, once again subjecting you to the the problem of kerning with different fonts.

• A Small Caps and Old-Style Figures (SC＆OSF) font has standard capitals on the ‘uppercase keys’ and small caps on the ‘lowercase keys’, making it easy to add small caps, although existing text must be changed to lowercase for it to appear in small caps. Other expert fonts provide small caps in place of standard caps as well as a full range of f ligatures.
• Most modern small caps have a height that’s equal to the x-height of the font, the height of most lowercase letters. For best effect, however, small caps should be slightly higher. You can achieve this by simply increasing the font size of these characters by half a point.

Measuring Fonts

The standard measurement for printing is the point (pt). The European (Didot) point is ¹⁄68 of an inch or 0.0147″. The printer’s point, used in the United States and the United Kingdom, is only 0.0138″, but on a Mac OS computer this is approximated to ¹⁄72″ or 0.01389″. A monitor with a resolution of 72 dots per inch (dpi) shows each point as a individual pixel.

The following information is provided for reference:-

Font Size

The size of a font is defined as the distance from the top of the highest ascender to the bottom of the lowest descender. In most instances this should be equal to the distance from the baseline of one row of text to the next, assuming that special leading isn’t used (see below).

• Newspaper print is often in a 9-point font, typically in Times.
• Fonts with a large x-height and small ascenders and descenders look big for their size.

Leading

The line spacing or leading used with a font is measured between the baseline of each row. If lines are spaced by 14 points the line is said to use 14 point leading. The term 12/14 means that a 12-point font has been used with 14 point leading.

• Applications can automatically set the leading to 120 % of the font size, such as 10 point with 12 point leading. This arrangement with the Palatino font provides a readable book style.

Styles and Weights

The style of a font can significantly changes it’s appearance. With a PostScript font each style is usually treated as an entirely different font. With the TrueType system, however, a computer can create styled text by modifying a plain font. For example, italic text is produced by slanting a normal font at an angle. Although the results aren’t perfect, they’re certainly adequate for domestic use.

The weight of a font determines the thickness or heaviness of each character. Here are the common weight names used for PostScript fonts, given in ascending order:-

The styles used in text are important if you want to create a slick presentation. Generally speaking, you should try to avoid using too many fonts and styles on any one page.

The following types of style are in common use:-

Special Characters

A computer keyboard generates around 219 different characters, most of which can be reproduced by traditional PostScript and TrueType fonts, whilst the other characters and symbols for international languages can be generated using OpenType fonts.The following points are worth noting:-

• The outdated QuickDraw GX fonts accommodate up to 65,000 different characters.
• Prior to Mac OS 8.5, the standard Apple fonts don’t have the Euro currency symbol (€). You can use the word Euro or ECU (European Currency Unit), although the latter isn’t really the same thing. Better still, you can use a special Euro font that only contains this character.
• Apart from letters, numbers and punctuation, some fonts contain shapes and symbols that are unrelated to the standard keyboard characters. These are known as dingbats.
• The symbols contained in a font often can differ from those found in other fonts. This means that when you change a font used for the text you’ll also change the symbols.

The following notes refer mainly to the Classic Mac OS.

Punctuation and Accents

Quote Marks

Curved single and double quote marks always look more professional than straight marks. You can usually generate these on a keyboard by pressing Option or Shift-Option along with the [ or ] keys. Fortunately, many types of word processor generate these smart quotes automatically, converting straight quotes into the curved variety as you type.

Feet and Inches Marks

Most people use standard single and double quotes for feet and inches. However, these aren’t really correct. Instead, you should perform one of the following, as shown in order of preference:-

• Select the Symbol font and press Option-4 or Option-,
• With some fonts press Option-Shift-Z or Option-Shift-G
• Use italicised straight quote marks

Ellipses

The ellipsis character (…) is produced by pressing Option-;, which is better than a string of full-stops (periods). If the character comes at the end of a sentence you should put any punctuation first. And you should avoid using spaces before or after an ellipsis, unless it’s at the end of a sentence.

Diæreses or Umlaut

This is the double-dot or bar that appears over a vowel that’s sounded separately, as in:-

In most fonts you can get this pressing Option-U followed by the required letter.

Non-keyboard Characters

On a Classic Mac OS computer you’ll find that the last four characters in every font can’t be used. These are represented by the numbers 252 to 255 (hex FC to FF), which aren’t normally generated by the keyboard. However, you can use a macro application such as KeyQuencer to produce these values, providing your chosen trigger keys aren’t used for other characters.

The following table shows how such characters can be generated using KeyQuencer:-

You can obtain each character for pasting into each macro by using a special utility such as PopChar Pro, although some macro applications allow you to enter the character directly as a number.

• Some fonts produce rather more exciting characters for these codes, such as the special arrows in Zapf Dingbats or the curvy bracket elements in the Symbol font.
• If you don’t have a macro application you can copy special characters from a document that already contains them and paste them into a new document.

Standard Mac OS Characters

The characters described below can be found in most fonts used with the Mac OS.

International Characters

Many international characters can be produced by using the deadkeys (see above). Other characters can be generated by pressing one of the special key combinations shown below, although some of these don’t actually work with older versions of fonts or elderly editions of the Mac OS. To obtain the characters shown in the right-hand column you must also hold down the Shift key.

Quote Marks

The normal forms of quote marks are as follows:-

although some countries use different characters to enclose text or for expressions, such as:-

Dashes and Dots

The different types of dashes and dots include:-

Special identifiers

These characters can be used to mark the start or end of a section of text:-

Keys		Character
Shift-8	*	Asterisk
Option-8	•	Bullet
Option-T	†	Dagger
Shift-Option-7	‡	Double-dagger
Shift-Option-V	◊	Lozenge
Shift-Option-K		Apple symbol

Currency Symbols

Various currency symbols are available, although different results can be produced, depending on whether you’re using the British or US form of keyboard layout, as shown below:-

• The euro symbol (€) is only available in modern versions of fonts.

Mathematical Symbols

Numerous characters, some of which are also used for other purposes, are used in arithmetic and maths. The following are used for arithmetical operations:-

while the following symbols are used to express relationships:-

and the following special symbols are used in calculus and logic:-

The final set of characters in this section are used for various purposes:-

Fractions

The size of a numbers in a fraction should be just over half the size of a standard character. For example, fractional characters in 12-point text should be in a 7-point font while those in 10-point text should be 5.5-point or 6-point. You should use a superscript font for the top number and press Option-Shift-1 in the regular font size to get a slash at the correct steeper angle. Note, however, that this kind of slash appears almost vertical when used for an on-screen presentation.

Printing Marks

The following special characters are commonly used in printing:-

©Ray White 2004.