[Q] How to properly include a subtitle?

[DrChiper]

Yesterday I saw an excellent explanation on how to use subtitles in combination with Kobo e-readers. I knew it was possible, but somehow never implemented it. I decided to bite the bullet and give it a go.

Thereafter, I was figuring: how to add those subtitles actually INSIDE the e-books so they exist outside calibre too (without adding them to the<title>)? There is no defined tag <subtitle> or is there? In short: What might be a proper way to do it?

I have seen some constructs in the .opf files like:

<metadata>
<meta name="calibre:title_sort" content="Sherlock Holmes"/>
</metadata>

I can add something like:

<metadata>
<meta name="calibre:title_sub" content="The Complete Novels"/>
</metadata>

But makes this sense?

[kovidgoyal]

IIRC epub3 metadata has support for subtitles, though I dont recall the details offhand.

[DrChiper]

Yes, I found it:

Name: title-type
Description: 	
The title-type property indicates the form or nature of a title.

When the title-type value is drawn from a code list or other formal enumeration, EPUB creators SHOULD attach a scheme attribute to identify its source. 
When a scheme is not specified, reading systems SHOULD recognize the following title type values: main, subtitle, short, collection, edition and expanded.

Allowed value(s): xsd:string
Cardinality: zero or one
Extends: dc:title

With example:

<meta refines="#ID12345" property="prism:contentType">article</meta>
<meta property="dc:title" id="t4main">
   Meet The Rejuvenated, Revitalized LeBron
</meta>
<meta refines="#t4main" property="title-type">main</meta>
<meta property="dc:title" id="t4sub">
   After a tumultuous first year in Miami, LeBron James locked himself
   in his house, rued disappointing his teammates—then worked hard to
   hone his game. The result: one of the best seasons in NBA history
</meta>
<meta refines="#t4sub" property="title-type">subtitle</meta>
<meta refines="#ID12345" property="dc:creator">LEE JENKINS</meta>

Hmm, I fear the whole thing would be moot as it is unlikely that any e-reader currently is able to use this. OTOH: it could prepare e-books for the future.

[JSWolf]

Originally Posted by DrChiper

Yes, I found it:

Name: title-type
Description: 	
The title-type property indicates the form or nature of a title.

When the title-type value is drawn from a code list or other formal enumeration, EPUB creators SHOULD attach a scheme attribute to identify its source. 
When a scheme is not specified, reading systems SHOULD recognize the following title type values: main, subtitle, short, collection, edition and expanded.

Allowed value(s): xsd:string
Cardinality: zero or one
Extends: dc:title

With example:

<meta refines="#ID12345" property="prism:contentType">article</meta>
<meta property="dc:title" id="t4main">
   Meet The Rejuvenated, Revitalized LeBron
</meta>
<meta refines="#t4main" property="title-type">main</meta>
<meta property="dc:title" id="t4sub">
   After a tumultuous first year in Miami, LeBron James locked himself
   in his house, rued disappointing his teammates—then worked hard to
   hone his game. The result: one of the best seasons in NBA history
</meta>
<meta refines="#t4sub" property="title-type">subtitle</meta>
<meta refines="#ID12345" property="dc:creator">LEE JENKINS</meta>

Hmm, I fear the whole thing would be moot as it is unlikely that any e-reader currently is able to use this. OTOH: it could prepare e-books for the future.

I've never seen an instance where have a subtitle would cause an iseue. But in most cases, it would be ignored.

[DNSB]

Originally Posted by DrChiper

Yesterday I saw an excellent explanation on how to use subtitles in combination with Kobo e-readers. I knew it was possible, but somehow never implemented it. I decided to bite the bullet and give it a go.

Personally, I just use the subtitle capability in the Kobo driver along with a custom column (very boringly called subtitle) where I can copy/paste the subtitle for the few books where it is worth while. Most the of subtitles I see are more along the lines of "Book Title: An exciting fantasy novel perfect for the fans of <insert list of authors>" or "Book Title: A Novel".

Adding non-standard metadata into the ePub would not be all that useful, IMHO. calibre already stuffs that into one of it's metadata content block.

[Quoth]

Originally Posted by DNSB

Personally, I just use the subtitle capability in the Kobo driver along with a custom column (very boringly called subtitle)

…

Adding non-standard metadata into the ePub would not be all that useful, IMHO. calibre already stuffs that into one of it's metadata content block.

+1 on all that.
Wife does like the subtitle on "My Books" list on Kobo now that I've started putting a piece of the Blurb or other description in it even if there is no subtitle.

Obviously because a title can be in any number of collections no collection is shown there, so the subtitle can give a clue to genre and flavour etc when viewing unread Titles sorted by Recent.
Though if a book is in a Series that's a good clue. Sometimes we deviate from original official series name if that's too generic.

[DrChiper]

Originally Posted by DNSB

Personally, I just use the subtitle capability in the Kobo driver along with a custom column (very boringly called subtitle) where I can copy/paste the subtitle for the few books where it is worth while. Most the of subtitles I see are more along the lines of "Book Title: An exciting fantasy novel perfect for the fans of <insert list of authors>" or "Book Title: A Novel".

Granted. I myself have just a few e-books showing subtitles. But I have e-books from various authors and different publishers using all the same title (I guess originality is out these days ). In those cases it is handy to differentiate with the subtitle (which amazingly all those books have also).

Originally Posted by DNSB

Adding non-standard metadata into the ePub would not be all that useful, IMHO. calibre already stuffs that into one of it's metadata content block.

Indeed. But as some subtitles can be meaningful, they are now present only in the calibre database and not inside the e-book itself: hence they can get lost.
Further, I did found about 78 EPUB3-ish books in my collection, of which only 2 did use the subtitle element. One in the .opf file as follows:

<metadata ...>
    <dc:title id="maintitle">The Title</dc:title>
    <dc:title id="subtitle">An Interesting Subtitle</dc:title>
    . . . 
    <meta property="title-type" refines="#maintitle">main</meta>
    <meta property="display-seq" refines="#maintitle">1</meta>
    <meta property="title-type" refines="#subtitle">subtitle</meta>
    <meta property="display-seq" refines="#subtitle">2</meta>
    . . .
</metadata>

and one in the HTML file:

<div epub:type="fulltitle">
  <h1 class="BookTitle" epub:type="title" lang="en">Main Title</h1>
  <h2 class="BookSubTitle" epub:type="subtitle" lang="en" role="doc-subtitle">An Interesting Subtitle</h2>
</div>

So indeed, usage and adding of subtitles seems very rare and probably not worth the effort.