eBook sizing dilemma

When I put my draft ephotobook out for student feedback, a technical issue with displaying the online published version was identified. I’d tested it on my MBP and I’d tested the ePub download on a iPad, but the online version wasn’t displaying correctly on the iPad (not opening to fill the full screen and not good). I’d used ID’s own iPad Pro sizing for the book.

Research

I’ve done some research on fixed flow ebook sizing and summarise here.

  • Different mobile devices have different screen dimensions and my own ebook will hopefully be viewed on a large computer screen more than a mobile device. Rather than sizing specifically using an iPad preset, it is better to size for 16:9 as a ratio that works better across different devices (including conventional laptop screens). For side by side pages, this becomes 8:9.
  • ‘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.’ (ebookpartnership). Glad I’m forgiven and surprised that ID’s presets didn’t allow for this. Apparently Amazon recommend double the pixel size of the device (to allow 2x zoom) and Apple 1.5x. Painfully, this also has implications for the sizing of my image files that were resized to an iPad’s pixel dimension. I need to find a compromise for laptop screens too (where I wouldn’t see a need for zooming in). The same guide recommends a long side of at least 3840 pixels. My ID preset has 2224!
  • Page numbering – I noticed that the device reader’s own page numbering is different to that I’ve put on the pages. I paged as I wanted the numbers displayed as a paper book – it is better to page as they will display in the ebook reader (ie cover is page 1). Another example of an ebook being a different animal.

I’ve also thought more about the format of the ebook. My original idea was to make it available as an ePub, but there may be disadvantages of using a fixed layout ePub against a PDF, given I’m not planning to sell the book online. The main one being that the ePub is device/application dependent for the viewing experience, whereas the PDF is not. This would seem to offer more control over the viewing experience. The other consideration is the use of ID’s online publishing – essentially this is a web-based viewing experience and if many people are going to simply view online, formatting for that space perhaps needs to take precedence. It does give the option of allowing the viewer to download a PDF directly from the online view, which could be a neat solution for my purposes.

Practice

Having researched and thought this through, I’m going to try the approach of sizing for online display at 16:9 with long-size pixel dimensions of 2560 as somewhere between HD and 4k. I’ll aim to create the illusion of a spread, so will split this into two 8:9 facing pages. I’ll then test how well ID exports from its web viewer to PDF (including multimedia) – viewers can then download if they wish to / I can include the PDF in the submission for the work (as an alternative on online viewing, which can be affected by poor internet connections).

The outcome / any adjustments will be included in my submission for A3.

Quick references

Tech sizing guide – https://ebookpartnership.com/support/knowledge-base/preparing-files-fixed-layout-ebook-conversion/

Pixel dimensions for screens – https://www.shutterstock.com/blog/common-aspect-ratios-photo-image-sizes

Apple device pixel dimensions – https://developer.apple.com/library/archive/documentation/DeviceInformation/Reference/iOSDeviceCompatibility/Displays/Displays.html

On monitor resolutions – https://www.digitalcitizen.life/what-screen-resolution-or-aspect-ratio-what-do-720p-1080i-1080p-mean

Note – other information is available online but it seems surprisingly sparse, with much of it based around self-promotion of own platforms.