They allow your word processor to tell you how your document layout works.
Know your layout
Earlier this year, someone walked past while I was word processing and noticed my screen was full of odd characters.
Usually people who notice this go “Aargh! Hideous!”, but this time the response was “That looks useful”, and it is. The blue symbols are non-printing characters, and they show why your layout is happening. As the name implies, they only appear on your screen, not in print, or when you export to PDF.
How do I see them?
In most word processors, non-printing characters are indicated by a ¶ symbol, which is also known as a pilcrow.
Go the the “Home” tab of the ribbon, find the “Paragraph” section and make sure the “¶” button is enabled.
Once enabled, the non-printing characters appear as shown below. An unusual feature is that it places a large black square at the start of lines that have “Keep with next” enabled under “Text flow”. This is a common format for headings, as it guarantees that, if the paragraph immediately following the heading wraps onto the next page, the heading will move with it.
Find the “Standard” toolbar, and make sure the “¶” button at the right end is enabled. This option may also be found in the “View” menu, under “Nonprinting characters”.
LibreOffice displays the characters much like Word, except that non-breaking spaces (see below) receive a grey background.
In Pages, non-printing characters are referred to as “Invisibles”. They may be enabled from the “View” drop-down menu on the toolbar, or in the “View” menu in the menu bar.
Invisibles in Pages are always coloured blue.
What do those symbols mean?
Spaces are what you type with the space bar.
Non-breaking spaces will “glue” words together so they can’t be separated over a line ending. The way you type them depends on your operating system, not your application. Under Windows, they are typed with ctrl–shift–space; under Mac OS, they are typed with option–space. If it is important that a name or phrase appear in full without being broken across a line or page, use a non-breaking space. Do not over-use them, or your line endings will be ragged1.
Paragraph breaks are what you type with the enter or return key2.
Line breaks move to a new line without starting a new paragraph. This will not be visibly different from a paragraph break unless the paragraph formatting includes space before or after, or special first line formatting. They will also wreck the layout of Justified text. Line breaks are entered with shift–enter or shift–return. This makes it easy to accidentally type a line break while intending to enter a paragraph break. Once typed, the only way to know that bad layout was caused by an accidental line break is to make the non-printing characters visible.
Tabs create a measured gap to the next piece of text on the same line. The exact spacing depends on the tabs set up in the paragraph format. Tabs are too complex to be fully discussed here, but once understood they can be used to create elegant layouts that are easy to edit. Type tabs using the tab key.
When should I enable non-printing characters?
I always have them enabled, even if I’m writing a simple letter. It takes a little time to adapt, but they help me detect and fix layout problems when I create the problem, before it spreads through a large document.
If you can’t stand typing with the non-printing characters visible, it is still good to enable them when you are formatting a document with complex layout.
- In HTML, non-breaking spaces are actually the intended purpose of the “ ” entity. Unfortunately we mostly misuse it to include formatting commands in our content. [↩]
- The “return” key dates from the time of typewriters. These had a “carriage return” lever that you pulled to move on to the next line. [↩]