Answers.Body: <p>Excellent question. To my knowledge there is no equivalent function in epub. In a web browser, RTA is done on the meta tag in your browser. But with epubs, you already have to store your Dublin Core metadata in the <strong>package.opf</strong> file, so there is no need to do so on individual html files. </p>
  
  <p>I skimmed the <a href="https://wiki.mobileread.com/wiki/Dublin_Core" rel="nofollow noreferrer">Dublin Core metadata</a> and did not see anything for an Adult label, although perhaps genre/audience/subject might be relevant here.  </p>
  
  <p>I knew that when you sell your ebook, Amazon or Google Play ask you to put a put it in a category (I later learned that they correspond to <a href="https://bisg.org/page/Fiction" rel="nofollow noreferrer">BISAC codes</a>). An <a href="https://www.oreilly.com/library/view/epub-3-best/9781449329129/ch01.html" rel="nofollow noreferrer">Oreilly article</a> mentions other categorization schemes like marc and onix. </p>
  
  <p>To summarize: The book creator usually can mention certain DC values which will be wrapped up in the epub. But I don't know of ebook reading systems which are using it to prevent the user from viewing it. On the other hand, when you submit your ebook to an ebookstore, they usually ask you to give some values that would allow the store to prevent younger readers from seeing it or buying it. </p>
  
  <p>But what if you are selling directly from your own website? What can you do? In addition to RTA labeling, you can require some proof of age to access the page or file. Ultimately though, when you are dealing with DRM-free ebook files, there is nothing preventing an underage user from loading it into an ebook reading system. </p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-08-30T16:12:23.303Z
Answers.LastActivityDate: 2019-08-30T16:12:23.303Z
Answers.UserDisplayName: idiotprogrammer
Answers.Body: <p>Schema.org provides an age range tag:</p>
  <p>&lt;meta property=&quot;schema:typicalAgeRange&quot;&gt;[start]-[end]&lt;/meta&gt;</p>
  <p>where [start] and [end] are numeric ages, and either (but of course not both) may be omitted. So adult material could be flagged as:</p>
  <p>&lt;meta property=&quot;schema:typicalAgeRange&quot;&gt;18-&lt;/meta&gt;</p>
  <p>Whether any website will actually look for this tag is another matter, though.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2023-06-16T05:43:14.330Z
Answers.LastActivityDate: 2023-06-16T05:43:14.330Z
Answers.UserDisplayName: angelusflat
Answers.Body: <p>What about <a href="https://schema.org/contentRating" rel="nofollow noreferrer">contentRating</a>? I guess</p>
  <pre><code>  &lt;metadata xmlns:dc=&quot;http://purl.org/dc/elements/1.1/&quot; xmlns:opf=&quot;http://www.idpf.org/2007/opf&quot;&gt;
      &lt;dc:identifier opf:scheme=&quot;UUID&quot; id=&quot;BookId&quot;&gt;urn:uuid:d09b7719-3094-492e-b817-bbffea9562a1&lt;/dc:identifier&gt;
      &lt;dc:language&gt;en&lt;/dc:language&gt;
      &lt;dc:title&gt;[Title here]&lt;/dc:title&gt;
      &lt;meta property=&quot;schema:contentRating&quot;&gt;Mature&lt;/meta&gt;
    &lt;/metadata&gt;
  </code></pre>
  <p>could work?</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2023-07-09T19:10:14.680Z
Answers.LastActivityDate: 2023-07-09T19:10:14.680Z
Answers.UserDisplayName: mcepl
Body: <p>I'm looking for the equivalent of the RTA header for websites but for ePub - something I can put in the metadata section to label the ePub as intended for an adult audience and not suitable for children.</p>
  
  <p>Does such a standard opt-in content rating system exist?</p>
  
Tags: <epub><metadata>
Title: ePub 3 option for age restriction metadata?
UserDisplayName: VeryGoodErotica
ThreadText: # ePub 3 option for age restriction metadata?
  
  (Asked by: username_0 on 2019-08-29)
  
  I'm looking for the equivalent of the RTA header for websites but for ePub - something I can put in the metadata section to label the ePub as intended for an adult audience and not suitable for children.
  
  Does such a standard opt-in content rating system exist?
  
  **Tags:** epub, metadata
  
  
  ---
  
  ## 3 answers
  
  ### Answer by username_1 on 2019-08-30. Score: 0 | Accepted answer
  
  Excellent question. To my knowledge there is no equivalent function in epub. In a web browser, RTA is done on the meta tag in your browser. But with epubs, you already have to store your Dublin Core metadata in the **package.opf** file, so there is no need to do so on individual html files.
  
  I skimmed the [Dublin Core metadata](https://wiki.mobileread.com/wiki/Dublin_Core) and did not see anything for an Adult label, although perhaps genre/audience/subject might be relevant here.
  
  I knew that when you sell your ebook, Amazon or Google Play ask you to put a put it in a category (I later learned that they correspond to [BISAC codes](https://bisg.org/page/Fiction)). An [Oreilly article](https://www.oreilly.com/library/view/epub-3-best/9781449329129/ch01.html) mentions other categorization schemes like marc and onix.
  
  To summarize: The book creator usually can mention certain DC values which will be wrapped up in the epub. But I don't know of ebook reading systems which are using it to prevent the user from viewing it. On the other hand, when you submit your ebook to an ebookstore, they usually ask you to give some values that would allow the store to prevent younger readers from seeing it or buying it.
  
  But what if you are selling directly from your own website? What can you do? In addition to RTA labeling, you can require some proof of age to access the page or file. Ultimately though, when you are dealing with DRM-free ebook files, there is nothing preventing an underage user from loading it into an ebook reading system.
  
  
  ---
  
  ### Answer by username_2 on 2023-06-16. Score: 0
  
  Schema.org provides an age range tag:
  
  [start]-[end]
  
  where [start] and [end] are numeric ages, and either (but of course not both) may be omitted. So adult material could be flagged as:
  
  18-
  
  Whether any website will actually look for this tag is another matter, though.
  
  
  ---
  
  ### Answer by username_3 on 2023-07-09. Score: 0
  
  What about contentRating? I guess
    
      urn:uuid:d09b7719-3094-492e-b817-bbffea9562a1
      en
      [Title here]
      Mature
    
  
  could work?
  
  
  ---
  
  