Word Spacing is the space between words that results from pressing the spacebar. This space is flexible; it can be expanded or compressed; it can be fixed and unchanging or elastic and adapt to circumstances.¹

Word spacing hasn’t always existed. Before the Middle Ages words and sentences were written without spaces in Latin or with interpuncts (small dots) in Greek and Roman texts. Spaces were added at irregular intervals before they were used between every word.² For the next five hundred years or so, printed books were usually set with close word spacing.³ Why there were no spaces, why spaces were added, and what effect adding spaces had on grammar, reading silently, and reading in general, are still debated in academia.⁴

Font designers today create a specific glyph for the space character: Unicode U+0020 Space (SP), so word spacing is initially defined as part of the font in use. Designers think of word spacing in proportion to the width of the typeface but vary in how that proportion should be derived—a sixth of an em, a quarter of an em, close to the width of a lowercase o, or close to the width of a lowercase i.

Reading experts too disagree on how word spacing, what they call inter-word spacing, affects reading and comprehension. Some consensus that large spaces between words could aid in acquiring the skill of reading might exist, but whether that benefit continues for those who have acquired the skill of reading or those readers with dyslexia, remains controversial.⁵

Unicode provides a unique number for every character, no matter what the platform, program, or language is. Read more about Unicode.

Adjusting Word Spacing

Adjusting word spacing is not kerning the space between two letters nor tracking the space between multiple letters. It is leaving these spaces the same and adjusting just the space between a pair of words, multiple words, or all the words in a paragraph or document.

InDesign uses the term word spacing to indicate two different things. Only one of these, handled at the formatting paragraph level, is word spacing as defined above (altering the width of the space character). The other, handled at the formatting character level, is really kerning between the space character and the letter to the right of it.

CSS has a property for word spacing, called word-spacing, which doesn’t specify the actual word space value but instead adds to or removes from the space character of the font in use.

Word Spacing at the Character Level in InDesign

The only way to adjust the spacing of multiple words, but not the entire paragraph, is to use the keyboard.

To increase or decrease the apparent word spacing, select a series of words and use the keyboard shortcut Cmd+Opt+Backslash to increase word spacing or Cmd+Opt+Delete to decrease word spacing. This will keep the kerning to the right of all space characters at 0 and adjust the kerning to the left of the space character up or down. If you click between the space character and the letter to its right, you can view the adjusted kerning in the character palette.

The chart below shows the keyboard combinations related to word spacing, kerning, and tracking. The only difference between kerning and tracking, which have the same keyboard shortcuts, is the selected text. If your cursor is placed between two characters, you will be kerning. If you have selected a range of characters, you will be tracking. Note: Tracking is applied on top of kerning, “Tracking and manual kerning are cumulative, so you can first adjust individual pairs of letters, and then tighten or loosen a block of text without affecting the relative kerning of the letter pairs.”⁶

Keyboard shortcuts often have modifiers that amplify what they do. These modifiers are shown in the chart with an unfilled circle. Holding this key down along with the keyboard shortcut amplifies the increment used by five.

The number used for the keyboard increment is set in Preferences under Units and Increments > Keyboard Increments > Kerning/Tracking. This number is in thousandths of an em (1/1000 em). For example, a quarter em would be 250.

Word Spacing at the Paragraph Level in InDesign

True word spacing is set as an option in the justification settings for paragraphs. Word Spacing values are set as Minimum, Desired, and Maximum. These values can range from 0% to 1000%, with 100% meaning no additional space is added or removed from the font’s space character.

To force Indesign to change the word spacing for a given paragraph, you need to change the value for the Desired setting.

You can use the panel menu on the upper-right corner of the paragraph palette to access the justification options. The Desired setting cannot be smaller than the Minimum or larger than the Maximum, so you might need to adjust these as well.

Note: Because this is a paragraph palette adjustment, simply clicking in the paragraph and changing options will apply changes to the entire paragraph.

The kerning to the left and right of the space characters is not altered.

Word Spacing in CSS

You can use the CSS word-spacing property to increase or decrease word spacing. The default value is normal or 0 which means the font in use determines the space between words. A positive or negative value for word-spacing adds to or removes from this width.

Note: While InDesign uses the 1/000 ems for kerning and percentages for word spacing, CSS allows for a variety of length units including ems but not 1/1000ems. So, a quarter em is 250 in InDesign and 0.25 in CSS.

Since the typical length of a space character is a quarter em, setting the word-spacing property to -0.25 em will remove word space completely, 0.25 will double it, and -0.125 will halve it.

General Guidelines

Word spacing doesn’t exist in isolation. It is affected by a number of decisions like letter spacing, glyph (character) scaling, font size, font weight, and the stylistic choices of the font designer.

• Narrow or condensed typefaces require closer word spacing.
• Generously drawn typefaces can have wider word spacing without looking overspaced. (Dowding, p. 8)
• White type reversed on black will need slightly wider word spacing. (Dowding, p. 9)
• As the font size increases, word spacing can decrease.

Word spacing is also affected by hyphenation, line length, length of the text, and even text content and intended use. InDesign also uses the information included in a font and user settings to launch the complex interaction of processes InDesign calls composition⁷ which also affects word spacing.

Adjusting word spacing on a character level is done to finesse awkward line breaks.

• “A sixth of an em (m/6) is an appropriate minimum word spacing for much of your text and you should aim for an average band of a fifth of an em (m/5). However, with some faces (especially those widely cut) this will not be enough.” (Dowding, p. 10)

• For ragged body text (aligned left), word spacing is generally recommended to be within 10% of the ideal 100%, so 90% min to 110% max, but never less than 60% min (Felici, page 146).⁸

• For justified text, the recommended range extends from 85% to 125% (Felici, page 146).⁹

How can you tell word spacing has been set manually?

InDesign Preferences > Composition > Highlight

The Argument for Close Word Spacing

It is an undoubted fact, as Dowding states it, that lines and pages set with close spacing are easier to read than those set with wide. Our eyes track along a line of text taking in words in groups, not one at a time. If there are gaps of white between words, our eyes lose that tracking. “The normal, easy, left-to-right movement of the eye is slowed down simply because of this separation…the eye tends to be confused by a feeling of vertical emphasis, this is, an up and down movement, induced by the relative isolation of the words.” (Dowding, p. 5)

Close spacing also produces a more aesthetically pleasing page. “A carefully composed text page appears as an orderly series of strips of black separated by horizontal channels of white space. Conversely, in a slovenly setting, the tendency is for the page to appear as a grey muddled pattern of isolated spots.” (Dowding, p. 5)

Using White Space Characters

Instead of trying to kern to adjust the space between only two words, consider using another of the white space characters. Two of the methods above—paragraph justification and the word spacing keyboard shortcut—will have no effect on white space characters other than the space character.

References

¹ “Horizontal Motion,” page 26, in The Elements of Typographic Style by Robert Bringhurst. https://typographica.org/typography-books/the-elements-of-typographic-style-4th-edition/

² Space Between Words: The Origins of Silent Reading by Paul Saenger. Stanford Univerity Press. https://www.sup.org/books/title/?id=683 “Over the course of the nine centuries following Rome’s fall, the task of separating the words in continuous written text, which for half a millennium had been a function of the individual reader’s mind and voice, became instead a labor of professional readers and scribes. The separation of words (and thus silent reading) originated in manuscripts copied by Irish scribes in the seventh and eighth centuries but spread to the European continent only in the late tenth century when scholars first attempted to master a newly recovered corpus of technical, philosophical, and scientific classical texts.”

³ “The School of Close Spacing,” page 9, in Book Typography by Ari Rafaeli.

⁴ “Space and Silence” by Yin Liu, Medieval Codes, http://www.medievalcodes.ca/2015/02/space-and-silence.html “Saenger’s thesis may be attractive, not least the argument that a seemingly innocuous and subtle encoding practice – introducing a bit of white space between words in written texts – has had such far-reaching technological and social effects. But is there a straightforward causal relationship between word separation and silent reading? I’m not so sure. Silent reading was not invented in the Middle Ages. Evidence exists to suggest that at least limited forms of silent reading existed in Greece in the 5th century BC and throughout the classical period, although Greek texts at the time were written in scriptio continua. Latin texts in classical and late Antiquity, also written in scriptio continua, could be read silently as well.”

⁵ Galliussi, J., Perondi, L., Chia, G. et al. Inter-letter spacing, inter-word spacing, and font with dyslexia-friendly features: testing text readability in people with and without dyslexia. Ann. of Dyslexia 70, 141–152 (2020). https://doi.org/10.1007/s11881-020-00194-x “However, contrary to several studies (Bachmann, 2013; Marinus et al., 2016; Zorzi et al., 2012), but in line with other previous research (Damiano, Gena, & Venturini, 2019; Kuster et al., 2017), a general advantage in reading speed due to increased spacing, in both its components, was not found either in children with dyslexia or in typical readers.”

⁶ Adobe, “Kerning and Tracking in InDesign,” InDesign User Guide > Add content > Typography > Kerning and tracking, see the section, How kerning and tracking are measured, https://helpx.adobe.com/indesign/using/kerning-tracking.html

⁷ Adobe, “Text Composition,” InDesign User Guide > Add content > Text > Text composition, https://helpx.adobe.com/indesign/using/text-composition.html

⁸ Specifying Word-Space Ranges in Ragged-Margin Type, pages 145-6, in The Complete Manual of Typography by James Felici. https://www.pearson.com/store/p/complete-manual-of-typography-the-a-guide-to-setting-perfect-type/P100001416339/9780321773265

⁹ Specifying Word-Space Ranges in Text with Justified Margins, page 146, in The Complete Manual of Typography by James Felici. https://www.pearson.com/store/p/complete-manual-of-typography-the-a-guide-to-setting-perfect-type/P100001416339/9780321773265

Controlling Word and Letter Spaces, page 140, in The Complete Manual of Typography by James Felici.

Metrics vs. Optical Kerning, page 128, in InDesign Type by Nigel French.

Example Font: Adobe Caslon Pro, Regular

Example Text: from The Time Traders by Andre Norton (pen name of American writer Alice Mary Norton), 1958.