The What

Pipfrosch Press is a digital publishing company that is attempting to bring high quality natural history publications to a broad audience in the ePub format.

Much of what is published by us will be existing content that has been ported to ePub, some of what we publish will be fresh content. All of what we publish will be Open Access content, meaning social and financial class will not determine who has access to the content.

About ePub

ePub is an open standard for digital publications originally developed by the International Digital Publishing Forum (IDPF) and currently maintained by the World Wide Web Consortium (W3C).

There are many different standards for digital publications, including but not limited to ePub, PDF, Kindle, and iBook. Some formats, like PDF, use a completely fixed layout that does not lend itself very well to different screen sizes or the needs of some users to increase the font size or change the font in order to be able to successfully read the content. Other formats, like Kindle and iBook, are proprietary and require specific software from a specific vendor in order to read them.

The main advantage that ePub has over proprietary formats like Kindle and iBook is that the user is not dependent upon software from a particular vendor in order to consume the content. This is particularly important as it liberates the user from dependence upon a particular vendor, giving the user the freedom of choice in what software or hardware is used to access the digital book. It further allows special interest communities to develop software that meets their needs. For example, the European Digital Reading Lab (EDRLab) saw there was a desperate need for an ePub viewer that works well for users with visual impairments, so they developed Thorium.

A secondary advantage that ePub has over proprietary formats is that the publisher is not limited in what software is used to produce the digital content.

The main advantage that ePub has over fixed layout formats like PDF is that ePub allows the content to flow to adapt to the available screen height and width. This not only makes ePub a more enjoyable experience on the smaller screen devices likes phones that are now very popular, but it also allows users who need a larger font size or even a different font to be able to select a different font size or font so that they can consume the content.

A secondary advantage is that it is much easier to modify an ePub for content accessibility needs than it is to modify a format like PDF. Many libraries and schools will modify digital publications in order to meet the needs of users who have trouble accessing the content in its current state, including things like removing italicized text that can trigger dyslexia issues. That is much more difficult with PDF.

ePub is not the best format for all digital content needs. Comic books for example are very difficult to correctly do with ePub and are probably better off being published in a format like Comic Book Archive.

For the content that Pipfrosch Press is interested in publishing, ePub is the best choice.

ePub Internals

This section is a bit lengthy and geeky 🤓.

An ePub is just a zip archive of files that meet a particular specification. Any ePub can be unpacked by unzipping the archive.

Internally, an ePub is a collection of largely XHTML files that are bound together with a digital spine but also allow navigation with hyperlinks. The specification allows for XHTML pages that are not bound within the digital spine and are only accessible via hyperlinks from pages that are bound within the spine. However in testing, Pipfrosch Press found that the way different eBook viewers handle this is inconsistent and in some cases handled quite poorly, so all XHTML pages in a Pipfrosch Press publication will be bound in the so-called digital spine. More information about the spine can be found at the EDRLab page ‘Anatomy of an EPUB 3 file’.

Most ePub archives have a cover image that acts as the book cover, providing an image that the eBook viewer user can turn into a thumbnail allowing the user to recognize the book and select it from within their digital library. There are numerous different recommendations for the size of the book cover image, Pipfrosch Press uses 1072 pixels wide by 1448 pixels high (1.35:1 portrait ratio). This is smaller than what many eBook vendors recommend, but what most eBook vendors recommend is in my opinion a waste of space. The cover is generally only seen in the context of the digital library where it is usually down-scaled from even the size Pipfrosch Press uses.

Every ePub archive has a specially formatted Table of Contents file that allows the eBook viewer to assist in user navigation in a consistent way that is the same for all books in the library. This Table of Contents format does allow for a multi-level hierarchy beyond two levels however in my personal experience I have found that many eBook viewers do very weird things if more than one sub-level is used, so Pipfrosch Press only uses main entries and one sub-level in this specially formatted Table of Contents. Within the spine pages, there may be additional Table of Contents that could have more than two levels if needed.

The Table of Contents can be quite large and difficult to navigate, so the ePub 3.2 standard allows for a ‘landmark’ contents format that makes it easier for the user to find specific parts of the book. Most eBook viewers do not yet implement landmark navigation but Pipfrosch Press implements landmark navigation for the benefit of viewers that do implement it.

An ePub does not have the concept of fixed page numbers, the pages are dynamically generated based upon the available screen space. This can cause issues when the publication is also available in print and a specific page number is referenced. To mitigate this issue, ePub 3.2 has a means of specifying where page breaks occur in the print published version of the book, along with the corresponding print page number. These page numbers can then be referenced in a Table of Contents specific for pagination. Most eBook viewers do not yet support this feature but Pipfrosch Press implements this feature for the benefit of the few that do (such as Thorium and R2 Reader).

An ePub may include font files supplied by the publisher. The ePub 3.2 specification allows for both TrueType and OpenType fonts (TrueType is actually just a special type of OpenType font) as well as compressed ‘web fonts’ using WOFF or WOFF2 compression. Unfortunately very few eBook viewers support WOFF2 and while many do support WOFF, I have encountered some that do not. As such, Pipfrosch Press only uses TrueType and OpenType fonts without compression. In the future when WOFF2 compression becomes virtually ubiquitous with eBook viewers, Pipfrosch Press will switch to WOFF2 compressed fonts.

The ePub standard allows for obfuscation of font files so that commercial fonts can be included but the very idea of resource obfuscation is offensive to Pipfrosch Press and it can interfere with the legal ability of the user to share the digital book with others, violating the concept of Open Access. Pipfrosch Press only includes font files that are legally redistributable without royalty and without obfuscation of the resource.

It should be noted that most eBook viewers allow the user to ignore the publisher provided font files and some ignore the publisher provided font files by default, requiring the user to specifically state they want to use the publisher provided font files when viewing the digital book. The ability for the user to ignore the publisher fonts is actually a good thing and is one of the many reasons I prefer ePub over PDF.

The ePub 3.2 standard allows the inclusion of vector graphics via SVG. The advantage of SVG is that it allows the graphic to properly scale without artifacts to the available screen space, regardless of how big or small the screen is. Vector graphics are not appropriate for photographic content, but for illustrations Pipfrosch Press always uses SVG.

The ePub 3.2 standard allows for the inclusion of mathematical equations represented with MathML. Unfortunately many eBook viewers have very poor MathML support. When equations are present in a publication, Pipfrosch Press does use the MathML code however what is rendered on the screen is currently an SVG visual representation of the equation. Some people in the digital publishing world are working on a solution that will make it easy for eBook viewers that do support MathML to ignore the SVG and render the MathML directly, Pipfrosch Press will adopt that method when it is available. This method being developed is critical to proper content accessibility where the user may need the ability to specify the font used for math equations in order to reduce the impact of dyslexia. Specifying the font used is not possible with an SVG representation of the mathematical equation.

The ePub 3.2 standard allows for the inclusion of both audio and video multimedia content. It must be understood that many hardware eBook viewers, such as the Kobo, simply do not have multimedia capabilities.

For natural history content such as frog calls and birds songs, audio content can be very beneficial and will likely be included in some Pipfrosch Press publications. Pipfrosch Press will use Ogg Opus for this audio content. This means these audios will not work on Apple devices, take that up with Apple. They have been stubborn about supporting Ogg Opus on Apple devices and seem to only be a company that cares about the best interest of the user when it is highly profitable to care.

The issue with AAC is that it is a patent encumbered audio codec. I can encode audio with AAC but I have to violate patent law to do so on Linux which is my operating system of choice. The issue with MP3 is that it requires a very large file size to get decent audio quality compared to Opus.

Every eBook viewer that supports audio that I tried had proper support for audio encoded with Ogg Opus with the exception of Apple Books. I consider Opus support to be ubiquitous and Apple Books to be a flawed product in that respect. What is really maddening to me, Apple does now support Opus in the context of RTC as Opus is part of that standard but Apple still refuses to support it in an Ogg (or any other multimedia file) container.

Pipfrosch Press has no plans to include video content in any ePub publication.