Sigil e-book editor in a new incarnation

Validating E-Books

E-books created in Sigil's book view and not subsequently manually modified don't really need syntax checking. If the e-books originated from an Office package and were then modified, a validation is highly recommended. Sigil provides a whole range of tools to do this.

Validating with F7 or Tools | Validate EPUB With FlightCrew checks whether your e-book meets EPUB standards. Sigil shows the results in a little window at the bottom edge across the whole width of the screen. Sigil documentation [9] describes what the output lines mean.

If FlightCrew is not enough for your purposes, Sigil developers recommend using the epubcheck command-line tool that you can download and install from the Ubuntu software repositories.

To check the validity of the CSS files, you can use Tools |Validate Stylesheets With W3C , which uses a web service to validate the files. Individual style sheets can be tested separately choosing an option from the context menu of the book browser.

You can remove conventional typos in Sigil with its integrated spell-checker using the Tools | Spellcheck menu. From the keyboard, use Ctrl+Q and F4 to jump from typo to typo.

The Tools | Reports menu is also quite useful. Style Classes in HTML Files , for example, finds special symbols and characters that get in the way of conversions. Other reports shows the amount and size of HTML, image, and CSS files. The Sigil user guide provides further tips for optimizing e-book structures [11].

Publishing E-Books

A few things need to be considered before publishing an e-book. First, you must consider where the book would appear. Amazon's self-publishing platform can simplify things, but it limits authors to restrictive rules and isn't very good when it comes sharing revenue (see the "Where to Publish?" box for more information). You should also proof the e-book's metadata and correct it if necessary. You can get an ISBN later through a publisher.

The metadata editor from the Tools | Metadata Editor menu or F8 might seem rather sparse at first glance, but it does allow you to add missing data such as a subject, title, or publication date. The Add Basic button, for example, adds dates, an available ISBN, and copyright information. The extent to which you want to go into this depends on your needs. It is often better to have the provider supply the metadata.

Be aware that many e-book publishers and self-publishing platforms accept EPUB formatted files only up to a certain size – if they accept EPUB documents at all. Often the limit is 16MB, so to avoid any problems, you should inquire about the file and image size limitations before committing yourself to a given platform.

Readers with smaller e-book readers also appreciate embedded images in manageable resolutions. Often an image of 800 pixels proves too wide. Smaller images will reduce the computational effort significantly, especially the width scaling.

Before you publish the e-book, you should also remove any unused files from the document. Sigil provides a tool for this from the Tools | Delete Unused Media Files and Delete Unused Stylesheet Classes menu.