Guidelines On Preparing For Fixed-Layout ebooks

If you are providing content for conversion to fixed-layout eBooks, the most common formats to submit are PDF and InDesign. The list below highlights some of the issues that may cause problems with conversion.

If you are using InDesign or similar software for designing files specifically for conversion to fixed-layout formats we recommend following these page set-up guidelines:

• Work in RGB rather than CMYK
• If possible use images of 300dpi
• Only use fonts that you are licensed to distribute
• Crop the pages – there is no need for page bleed or printer’s marks
• Ensure all pages are the same size
• When you output your files ensure that you do not flatten the text
• The manuscript should be complete (ie all pages within the file) and final when you send for conversion.

Page sizes:

We are often asked for the best page size to use when designing books to be converted into fixed-layout eBooks. This is a difficult question to answer, as unless you are targeting a single device – for example full size iPad or Kindle Fire HDX 8.9″ – you will need to produce files which will look good across a number of devices of different sizes and screen resolutions. As tablets and eReader devices are usually smaller than print books it is important to design your book to use as much of the available screen display as you can.

The two most important criteria to take into account when you set up your pages are:

• Page aspect ratio (the relationship between the width and height of the page (landscape) or height to width (portrait)
• Page dimensions (in pixels)

Page Aspect Ratio

There are many different devices that your readers may use to view your eBook on and not all devices have the same screen shape (width to height screen proportions – see the image below).

The iPad, which is the dominant tablet in some markets, has a different (squarer) screen shape to most other tablets.  If you are targeting iPad users as your key buyers, you may wish to design your pages using a 4:3 aspect ratio.

If you want to produce files that fit better to the display of other devices then we recommend that you work to a ratio of 16:9 (this takes into account the menu bar which sits at the top of many Android devices) or 16:10.

If your publication contains double page spreads that will  ideally be viewed in landscape, it makes sense to use the more square page shape. To fit two pages side-by-side on a 16:9  ratio screen, set them up to be 8:9 (half width, full height), or 8:10 on a 16:10 screen. With this approach you need to be aware that if the reader chooses to view a single page rather than two pages at a time (which some devices will allow them to do) that the single page will not fill the height and width of the screen, as the page is almost square and the screen is rectangular.

The NOOK Kids format can only be displayed in landscape so you will either need to produce single landscape pages (which will be displayed one at a time) or two-page spreads.

Page Dimensions:

The size of a digital display is usually measured using pixels rather than inches or cm. A list of the display sizes of some of the most popular tablets and eReader devices is given in the table below.

You could be forgiven for assuming that setting your page to be the same size as an iPad screen or Kindle Fire screen is all you need to do. However in order to create files that retain quality and definition when the reader zooms in, both Amazon and Apple recommend that you produce pages larger than the actual screen size.

In the Amazon Kindle Publishing Guidelines Amazon recommend producing files that are double the size of the Kindle Fire screen to support 2x zoom. So based on the dimensions of the latest Kindle Fire HDX 8.9″ tablet this would make your ideal page pixel dimensions 5120 x 3200 (full page portrait), or 3200 x 5120 (full page landscape) or 3200 x 2560 (each page of a double page spread).

The latest version of Apple’s iBooks Asset Guide recommends that content is produced at at least 1.5 times the screen size, which for the latest iPad Air would make the ideal page pixel dimensions at least 3072 x 2304 (full page portrait), or 2304 x 3072 (full page landscape) or 2304 x 1536 (each page of a double page spread).

DPI/PPI:

As your page will be set-up to specific pixel dimensions the DPI/PPI is somewhat irrelevant. However, you should ensure that any graphic elements you include within your file are sharp when viewed full size (we recommend using 300 dpi images).

Page Size Summary:

Depending on your time, budget and objective you may want to look at producing one file tailored to the display of Apple’s iPad, and another, less square file for other devices.

Producing fixed-layout eBooks from Word or PowerPoint

If you have produced your book layout in Microsoft Word or PowerPoint we recommend that you save the files as PDFs and use these as the basis for the fixed-layout conversion. In most MS Office applications you can simply use the ‘File > Save as’ menu item to save the file as a PDF.

Common Issues

Text size in KF8 files

As some Kindle devices have a relatively small screen and can only display a limited amount of content at one time, the best KF8 fixed-layout titles tend to be those where the content, and especially the text, is not too small. KF8 offers a feature called region magnification for devices that do not support touch screen zooming, and this allows the reader to double-tap on specific areas of the screen to enlarge a region of content. Region magnification is not suitable for all content layouts.

Amazon may de-list fixed-layout KF8 files where the text is smaller than 4 mm in height. This means that if your book is originally designed to A4 or Letter size, any text content which is smaller than 24pt in the original may be too small (less than 4 mm) when displayed on a Kindle Fire device.

If you have access to a Kindle Fire device, the quickest way to test the text size is save your file as a PDF and view your PDF on your Kindle Fire. When you view a page at full screen you can measure the text and see whether it is smaller than 4mm.

If you do not have a Kindle Fire, to estimate whether your text size may cause a problem you can do the following calculation:

• Measure the height of original file or book in mm.
• Divide the height by 28 for a landscape book or 41 for a portrait book (these numbers are explained below)
• The result of this is the minimum height in mm that text should be in your original file.

So, for example a landscape 10 x 8 book is 200 mm tall, divide this by 28 and you get roughly 7 mm. This means that any text in your original book which is less than 7mm tall may fall foul of Amazon’s 4 mm rule when displayed on a Kindle Fire device.

For another example,  a portrait 8 x 10 book is 254 mm tall, divide this by 41 and you get roughly 6 mm. This means that any text in your original book which is less that 6 mm tall be less than 4mm rule when displayed on a Kindle Fire device.

Why 28 and 41? The approximate dimensions of the screen on a Kindle Fire HD tablet are 110 mm on the short side and 165 mm on the long side, if you divide these measurements by 4 you get 28 and 41 (so the minimum text height is equivalent to 1/28 of the height of the screen in landscape and 1/41 the height of the screen in portrait).

Pop-up text in KF8 and Nook Kids files

When producing files which are going to include pop-up text it is important that you maintain a reasonable margin between the text and edge of the page (we recommend at least 1 cm when viewed at device screen size). This will prevent the in-built screen controls of some device interfering with the readers ability to activate the text pop-ups.

Using unlicensed fonts

Only use fonts that you have a licence to distribute. If you are unsure, choose fonts from a source such as Google Web Fonts or Font Squirrel which are clearly labelled as free to distribute. If you have a specific font that you wish to use for your book (and you have the appropriate license for use) the font can be embedded.

Page numbering

If you are adding page numbers we recommend using simple 1, 2, 3, etc with page 2 being the first page after the cover. Some retailers may reject eBooks that use a different numbering system (such as Roman numerals for the front matter). This is because the on-page numbers may not match the numbers generated by the device or the retailers own software/app.