I’ve written a lot about ebooks over the years, but very little on what makes them readable. That’s unfortunate, since the defaults you get with almost every ebook reader provide a sub-optimal experience. Every time I hear someone say, “I tried reading a book on my iPhone, but I just couldn’t do it,” and I look at their phone, I realize that with those settings I couldn’t do it either. So let’s go over what makes books readable in the first place and how to mimic that on your reader of choice.
The first and most obvious aspect of readability is of course the typeface you use. The right font can make or break your reading experience. Fonts come in two main styles, serif and sans serif. Serif fonts have small ornamental lines, called serifs, that give them a more stylized look and more importantly, guide the eye along the line of text. It’s for this reason that serif fonts have traditionally been favored by typographers for long stretches of narrative. Common serif fonts are Times Roman, Georgia and even the monospaced Courier.
Sans serif fonts tend to be much simpler letter shapes, as they lack the serifs. This makes them look cleaner on the page or screen, but in theory less readable over time in bulk paragraphs. Sans serif fonts have traditionally been preferred for on screen use because they’re simpler to render. Common sans serif fonts include Helvetica or Arial, the Verdana/Tahoma/Nina family and the handwriting-like Comic Sans.
So what’s best for ebook readability? That’s not an easy question. It’s worth noting that most people don’t actually read one letter at a time. Instead adult readers take in whole words, phrases and even sentences at a time. The pattern recognition on the brain is absolutely crucial, and anything that disturbs or alters the expected patterns will dramatically impede the reading process. For anything longer than a few lines, I prefer serif fonts. On a good serif font, the serifs really do guide the eye along the line and make reading more comfortable. If I’m on a lower resolution device and have to go with a sans serif font, I prefer something like Trebuchet MS, which at least has pseudo-serifs to differentiate letter shapes. Verdana, which was also designed expressly for on-screen readability, as well as it’s compressed sibling Tahoma—and the even further compressed Nina—is another good choice if you need to go sans serif.
So now that we know what kind of font to use, which fonts in particular are best? While there’s a certain appeal to Times or Times New Roman, the “default” proportionally spaced serif font, it was designed to be printed, and doesn’t always translate well on screen. It’s a very narrow font with comparatively little white space between lines, to allow news papers to cram the maximum number of words on the fewest possible pieces of paper.
If it’s available, I prefer Georgia, which was designed for on screen readability. It has a taller x-height than Times, which means the lower case letters are taller—and generally wider—for a specific point size than Times.It also has lovely serifs that evoke the typesetting on vintage hardcovers and a clear, script-like italics version.
If you’re using a newer device with TrueType turned on, Microsoft’s new Cambria or Constantia fonts look even better than Georgia, because they’re designed not only for on screen readability, but also to take full advantage of subpixel font rendering. Basically, these fonts make it appear that you have three times number of pixels that you actually have. Cambria has a more “informal” feel to it, with rounder letter shapes. Constantia is closer to Times with a lot of straight, vertical lines.
Okay, you’ve got the right font, now how big should it be? This is balancing act and frankly the hardest decision to make. It’s dependent on several factors.
First is line length. A good rule of thumb is that you should have on average about six to eight words per line. So if you pick a font that’s too big, you won’t get as many words per line as you should and reading will feel very “choppy” as your eye keeps darting back and forth very quickly. (Conversely, this is why it’s important to use giant margins or split text into columns on wide monitors. If the line length is too long, your eye tends to wander up or down to other lines before you get to the end and reset.)
But you also need to have a reasonable amount of white space. A lot of reader software will allow you to set your margins. Believe it or not, there’s actually an advantage to having healthy margins around the text. It helps the brain compartmentalize the text and keeps the page from looking too busy and overwhelming. Try it. You’ll be more comfortable with a reasonable margin than with text that goes right up to the edges of the screen.
White space is also a function of font choice, as your font will tend to define, at least at first, your vertical line spacing. One of the reasons I like Trebuchet MS so much is that in addition to being a serif-like sans serif font, it also defaults to wider than average line spacing, with more white space between lines of text. This makes it easier for the eye to follow long each line without jumping above or below and confusing things. This is also why the latest versions of Word default to 1.15x line spacing. That little extra white space really makes a difference in readability on screen.
So what’s the answer? It’s going to be different for everyone. Find a serif font you like and then try different combinations of margins, font sizes and if you can, line spacing until you find something comfortable at six to eight words per line. In eReader on my iPhone, that comes to Georgia at Medium font size, normal line spacing and wide margins. On the iPhone Kindle app my options are more limited, so I just go with the second of the five font sizes. In Stanza, my reader of choice, you can tweak almost everything and I have it set up with nearly ideal font, font size, line length and line spacing.
Let’s talk about paragraphs. Most of time, you’ll take what you get. Some books and some readers will give you indented paragraphs, like you see in most printed fiction, where the line spacing doesn’t change but the first line of each paragraph is indented slightly. Others will give you block paragraphs, where the first line of a paragraph is not indented, but there is a blank line between every paragraph and the next. If you have the option, go with indented paragraphs. They’re no easier nor harder to read than block paragraphs, and they let you fit more on each page, so you turn pages less frequently.
Another point to consider at the paragraph level is justification. Here I differ with the conventional wisdom. All the studies I’ve read say to go with unjustified, or “ragged” right margins, where the letter spacing is uniform and each line ends where you run out of words and have no room to fit the next word in the sentence. The uniform letter spacing makes it easier for your brain to read each word.
In justified paragraphs, the spacing between each letter or each word is tweaked just enough so that the end of the line makes a straight vertical line down the right side of the screen just as the left margin does. Personally, I like this better, even if it makes things just a bit harder to read. It looks more like a real book that way. I find ragged margins distracting, so for my money, justified is actually easier to read. It helps if your reader program supports automatic hyphenation, breaking big words across lines if they fall at the line end. This means you have virtually no instances of the big honking gaps that can occasionally happen with full justification, big words and shorter line lengths.
Okay, you’ve got all the typography down. What about color? On a lot of phones, you aren’t limited to just black and white. Oddly enough, though, you’re probably best off sticking with black text on a white background anyway. It offers the best contrast, which is going to lead to less eye strain. If you want to mimic the warmer feel of a paper book, you can change the background to an off-white or cream color without losing much in the way of contrast. A lot of readers allow for inverted colors for night reading with the lights off, but I find that you’re probably better off just dimming the brightness to a black on gray that you find comfortable. Light text on black doesn’t look very good with font smoothing enabled. In general, I would stay away from other color combinations, and please, never, ever use a graphic texture as your background. A lot of readers allow for this, and even make it the default, but it’s just going to distract your eye from the actual text. Yes, it’s very cool that you can make the background look like parchment, but don’t do this if you actually want to read the book.
A lot of books will scroll the text for you, like a teleprompter. While this seems like a good idea, in that you can read not actually needing to turn the page, I’ve never made it work. My reading speed changes depending on the text. Pages with a lot of dialogue I’ll get too much ahead of the scrolling and get frustrated because I have to wait, and pages with a lot of description or interior monologue I’ll have to start skimming just to keep up. Stick with turning each page one at a time for maximum readability.
And lastly, we come to all the other stuff your reader program can display that isn’t the book. Things like title, page number, time, buttons for all kinds of functions: find, annotate, bookmark, etc. If you can, keep these to a bare minimum. Every additional thing on the page is something your brain has to rule out every time you see it. On Stanza on my iPhone, I have just the progress bar—a thin line at the very bottom of the screen showing how much of the book you’ve read relative to the total length—and the standard iPhone status bar at the top. I could even hide the status bar, but I usually read in bed, and I need to be able to see the time so I know when it’s time to put the book aside and go the heck to sleep if I want to avoid being a zombie the next day. Simpler is better, in general.
And that’s it! Now you know enough about typography and how the brain actually reads text to make your ebook reading experience as close to or even better than reading a paper book.