Note: We highly recommend you read the Book Industry Study Group’s very thorough Field Guide to Fonts in eBooks.
Since the beginning of the printers craft, it has been common for typefaces to be designed with clarity and uniqueness in mind. One complaint leveled against the move to eBooks has been the lack of support for beautiful typography, which was actually true for a long time. However, with the advances in devices and formats in recent years, we have seen a major change in eBook design and typographical support, in many cases rivaling print design capabilities.
Despite these advances, on the practical level there are two major differences between how a print font works and how an eBook font works: Licensing Terms and Font Styles. These differences have a large impact on how eBooks are created it is important that all publishers and authors know about them.
When you purchase a font from a font company, or when you receive a commercial font with software like Windows, OSX, Word, InDesign, etc., you are licensing that font for use in specific circumstances. Typically, commercial fonts are licensed only for use on one computer system. While this does not matter for a print book, since the font file never leaves the computer on which it is being used, in eBooks the font file itself has to be embedded inside the eBook file. This means that every person who purchases the eBook has access to the actual font file. This access is not granted by most commercial font licenses, making standard fonts unable to legally be embedded into eBooks.
If a font does allow embedding, there are four kinds of embedding permissions that are possible:
For the purposes of eBooks, a font with any of the last three embedding permissions above should be able to be used in the eBook files. However, please note that in many cases the license will additionally require that the eBook be encrypted with Digital Rights Management (DRM) of some kind to make the extraction and illegal use of the font file more difficult. This can make selling your own eBooks on your website difficult, and may have other ramifications on your eBook sales efforts. It is always best to clarify the rights you have with the font licensor and ensure that you will not become legally liable for distributing the font just by putting it in your eBook files.
If you are using Adobe fonts in your book, there is a chance that those fonts have embedding permissions. You can see a list of those fonts here, as well as other information from Adobe about font embedding.
In order to see what licensing your fonts have, you will need to either look at the license that came with the font files you purchased, or open the font properties on your computer and look at the information there. If the license is not clear, or if you just want to make sure you have covered all of your bases, we recommend using a different font with an open license in your eBooks.
Open licenses allow a font to be embedded inside the eBook files without any special permissions, and in some cases allow you to actually change the fonts design or abilities to make it better fit your needs. There are a few locations where you can usually find open license fonts, most notably Google Web Fonts.
Many programs like Microsoft Word will allow you to just bold or italicize any font that shows up in the font list. However, font styles have to be applied differently in eBooks. If you are using an embedded eBook font and you want your text to be bolded or italicized, you have to embed an actual bold or italic version of the font in the eBook file as well. This limitation makes it more difficult to find versatile eBook fonts, and can be a complicating factor when trying to find replacements for print fonts.
Like computers, all of the major eBook devices and tablets include a list of fonts that are installed by default on the device. These fonts are sometimes common ones like Times New Roman or Arial, but many times they can be fairly unique. These device fonts are intended to allow readers to customize the formatting of the text to their own liking, just like changing the font size or margin widths.
While it is possible on most devices to make the eBook file use these fonts, there are a few issues with this approach that make it quite problematic. First, these device-specific fonts are subject to change at any time (for example, Apple did this in December 2011, removing some fonts from iBooks and replacing them with others). Second, these fonts are different on every device, and there is no way to make the file look the same everywhere if you are relying on device-specific fonts.
However, despite that, there are some use cases where calling the device fonts may be a good idea. For example if you wanted to style the text of a letter in a typewriter-style font, and you really like the American Typewriter in iBooks, then setting that as your primary font for iBooks, with a fallback to an embedded font, is a great idea.
Some terms that are commonly used in relation to fonts might be a bit confusing. Lets define these terms so that you are able to make better decisions about the fonts you use.
Serif: Fonts with a Serif typeface have small lines (serifs) trailing from the edges of the characters. Some common examples of Serif fonts are Times New Roman and Georgia.
Sans-Serif: Fonts with a Sans-Serif typeface do not have serifs on their characters. Some common examples of Sans-Serif fonts are Arial and Verdana.
Monospace: In Monospaced fonts, the characters are all designed to be the same width. This means that a lowercase i is the same width as a lowercase m. Some common examples of monospaced fonts are Courier and Monaco
Weight: The weight of a font refers to the thickness of the character outlines relative to their height. Weights follow the basic pattern: Hairline, Thin, Ultra-light, Extra-light, Light, Book, Normal/Regular/Roman, Medium, Demi-bold/Semi-bold, Bold, Extra-bold, Heavy, Black, Extra-black, Ultra-black
Regular or Roman: Roman fonts are what most of us consider to be the normal font style (i.e., not italic or bold).
Bold: Bold fonts have thicker lines and darker textures, and are commonly used for headings and for strong emphasis.
Bold Italic: As the name implies, these fonts are both darker and italic in design.
Italic: Italic fonts are typically designed to reflect their Roman counterparts, but are slanted to the right and made to slightly resemble handwritten or cursive text. These fonts are commonly used to show emphasis.
Oblique: Oblique fonts are distinct from italics in that instead of being a different character design, they are just a slanted version of the Roman typeface. Oblique styles are common among sans-serif fonts, and they serve the same function as italic font faces in publishing.
Condensed: Condensed fonts are styled the same as the regular font in the same family, but the characters are narrower, allowing more text to appear in the same space.
Humanist: A font style distinguished by a sloping bar on the lowercase e, a relatively small x-height, little variation in stroke width, and dark weight (more info).