Canonical Way to Specify Readable text for TV feeds: Pixels? I was reading an advertizing code which specifies:


  ""For TV Advertisements the size of the “Supers” shall be of minimum
  12 pixel height....."


This got me thinking: If readability / legibility is the goal, does it make sense to specify a pixel size? i.e. Won't the same font display as varying numbers of pixels depending on what kind of TV it is shown on?

If ensuring readability was the concern what would be the best way to specify the font size? A fraction of the total frame? Or something like


  "....to show up as at least 12 pixel on a 1080 pixel display"
Specifying text in terms of pixel size is the most independent way of specifying size. Where you know the vertical resolution (like 720 lines or 1080 lines) then specifying pixels is exactly like saying "a fraction of the total frame".

And in practical terms, 12 pixels is pretty much the minimum recognizable height for common western characters, especially if some viewers are watching on screens of lower resolution.