Dell U2515h also recognized as television

Discussion in 'Mac Accessories' started by MattTheMedic, Mar 9, 2015.

  1. MattTheMedic, Mar 9, 2015
    Last edited: Mar 10, 2015

    MattTheMedic macrumors newbie

    Oct 29, 2014
    I recently got the Dell U2515h monitor. I use it with an early 2013 rMBP in clamshell mode. First of all I know the text is fuzzier because the monitor simply has a smaller resolution at a larger surface (1440p@25inch). Nothing wrong here.

    I read at that OS X marks some (Dell) monitors as television and outputs YCbCr instead of RGB which caused fuzzier text and bad colors. I looked in system report and my monitor connected with MiniDisplayPort (thunderbolt port) to DisplayPort is also marked as Television : yes. When I looked in the monitor menu it tells me the color input is RGB. This leaves me to believe the macbook does output the right RGB color space. My question: does OS X change anything else apart from colors when it thinks the display is a TV? (like font smoothing)

    The text doesn't particularly annoy me (I knew it was going to be much worse than Retina) but since I come from a Retina display I can't determine if the text is supposed to be this way or if there's a problem because OS X sees the dell monitor as TV.

    UPDATE: When you get the right RGB signal, fonts do not get degraded, even-though the monitor is detected as TV.

    You can check the input signal by doing the following:
    - open the dell monitor menu > Settings > Color > Input Color Format
    - If the monitor lists RGB, you get the right color format. If not I'd recommend using the Force RGB patch:

    Attached Files:

  2. larrysing1963 macrumors regular

    Aug 16, 2014
    There are fixes for this. It involves downloading a script and executing it from Terminal.

    See here:,d.eXY

    You can also search "OSX force RGB mode" in your favorite search engine.
  3. MattTheMedic thread starter macrumors newbie

    Oct 29, 2014
    Thanks for your reply!
    I know there's a fix for this and understand how to use it.
    The problem is: I don't know if it's the same problem since my monitor says the signal is RGB already. I would like to know if OS X changed anything about the display besides RGB (e.g different font smoothing) because it thinks it's a TV.
  4. larrysing1963 macrumors regular

    Aug 16, 2014
    Yes, that script does modify the EDID at the o/s level. Users who created it say it makes the required difference in the performance. I did it to my P2715Q and to be honest, I couldn't tell much difference with the naked eye. I do not do professional video or photo work, however, so my eye is not as well-trained. :apple: ;)
  5. MattTheMedic thread starter macrumors newbie

    Oct 29, 2014
    Ok, thanks. I will try the script out, after making a backup of the original folder.
  6. bootz macrumors member

    Jan 7, 2014
    Here's some discussion on it:

    I've used other monitors with my mid-2012 15" rMBP via HDMI that identified it as a Television and the fonts looked terrible. Not so with the U2515H. I'm currently using the Dell-supplied mDP to DP cable. The image looks great in my opinion. Obviously not as sharp as my 15" rMBP display, but what else is?
  7. MattTheMedic thread starter macrumors newbie

    Oct 29, 2014
    Yes, the image is very nice. Like you say the text is not as sharp as on the rMBP, but that's to be expected. I was just wondering what OS X changed about the image when it thinks the monitor is a TV (besides outputting the wrong color space with some monitors). My monitor was detected as TV but OS X did give the right RGB signal. I did the patch talked about in earlier posts to see if removing the tv detection changed anything about the fonts.
    It didn't.

    Conclusion: If a mac detects the monitor as TV but outputs the right RGB color space there's nothing wrong with the fonts, nor can these be improved by letting OS X know the monitor isn't a TV. (At least with the Dell U2515h)

    It's nice to know that this monitor when connected to OS X still gets the best image possible and doesn't get a worse image simply because it's detected as TV.

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