title: How can I use add_filter for a specific page template?
body: <p>In Wordpress I have a page template called <code>designers.php</code>.</p>
  
  <p>When loading, it reads the <code>slug</code> to get a uniqe ID, then calls the DB to retrieve designer information.<br>
  I want to use this information to alter the page title, using the designer name in the title tag.</p>
  
  <p>I've tried using the <code>add_filter</code> in my <code>designers.php</code> file, but it's not working:</p>
  
  <pre><code>add_filter('wp_title', 'set_page_title');
  
  function set_page_title($title) { 
    global $brand;
    return 'Designer '.$brand['name'].' - '.get_bloginfo('name');  
  }    
  </code></pre>
  
  <p>I'm, guessing the <code>add_filter</code> must either be located inside a plugin or in <code>functions.php</code> file.</p>
  
  <p>How can I achieve what I'm trying to do?</p>
  
  <p><strong>UPDATE</strong><br>
  The function is never fired as long as I use <code>wp_title</code>. If I change it to <code>init</code> (for testing), the function is fired.</p>
  
  <p>So why does the <code>add_filter</code>nor work for <code>wp_title</code>?</p>