Imac 5k 2015 display quibbles

Discussion in 'iMac' started by Philflow, Jul 13, 2019.

  1. Philflow macrumors 65816

    May 7, 2008
    I bought a used late 2015 Imac 27 inch from someone. Colours look fantastic but I'm not 100% satisfied with the contrast, especially the black level.

    For example: it looks like black letters (especially on the top area of the screen) aren't as deep solid black as I'd like them to be. The black level isn't bad, but when I compare them to an old 24" inch TN display I have next to it, it falls slightly short. And that's a very cheap LCD.

    I'm wondering if I just got unlucky with this unit.

    Up on searching I found this review, that explains what I notice: "The contrast ratio is okay at 740:1 (average for workstation notebooks, for example) and is definitely sufficient for nice pictures."

    However, most other reviews measure around 1100:1 which is really what it should be.

    Does anyone know what might be going on?

    I've played around with the calibration profiles but that didn't solve it.
  2. mikehalloran macrumors 68000

    Oct 14, 2018
    The Sillie Con Valley
  3. Philflow, Jul 13, 2019
    Last edited: Jul 14, 2019

    Philflow thread starter macrumors 65816

    May 7, 2008
    Thank you. Yes I'm on Mojave. I ran the command
    "defaults write -g CGFontRenderingFontSmoothingDisabled -bool NO"

    and that does look a bit better.

    Still I was hoping for a higher contrast ratio. This isn't what I expected from 1100:1. It looks more like 800:1 as Notebookcheck measured. I wondering if I got unlucky with this unit.

    Apple only uses 1 type of display right?
  4. CWallace macrumors 603


    Aug 17, 2007
    Seattle, WA
    LG is the only supplier of 27" 5K displays so all iMacs use them.

    There are probably hundreds of posts (if not threads) about the "panel lottery" when it comes to iMac displays going back to the first non-Retina 27" models. As with all IPS panels, there is LCD light bleed along the edges and LG has gotten better with it over the years, but that might be part of the issue.
  5. ZipZap macrumors 603

    Dec 14, 2007

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