Apple, You Make It Hard: Mac Laptop “Retina” Screen Update #amwriting

In November, I wrote about giving your older Mac laptop a “Retina” screen by enabling it with SwitchResX. Well, I just upgraded my MacBook Air 11 to Mojave (MacOS 10.14.2) via a “clean install”, and it took away my beautiful high-resolution, pseudo-Retina screen! As an obsessive nerd, I could not possibly let that one stand.

It seems that years and years ago, I installed Apple’s dev tools, which enabled HiDPI (pseudo-Retina), unbeknownst to me. When I did a clean install of Mojave, I wiped out both the tools and the HiDPI capability. Oops.

Long story short, I found what I needed in this article, “How to Enable HiDPI Mode in Mac OS X,” by Jim Tanous. Here’s a summary of how to enable these delightful screen modes:

  1. Start from an account for which you have admin privileges.
  2. Open the Terminal app (you can find it in Applications/Utilities)
  3. Copy and paste the following command: sudo defaults write /Library/Preferences/com.apple.windowserver.plist DisplayResolutionEnabled -bool true
  4. Press return. Terminal will ask for your admin password. Provide it and press return.
  5. Restart your Mac.

Now HiDPI (AKA “Retina”) resolutions should be available in the SwitchResX menu, assuming your laptop screen is capable. Enjoy!

If you’ve never used Terminal before, here’s a quick breakdown of what’s happening in its screen.

N.B.: This works because of two effects: SwitchResX enables you to go to a scaled resolution larger than the largest “native” resolution on many monitors (AKA “stretched” resolution)—including the MacBook Air 11 built-in monitor. Enabling HiDPI enables you to use a “half-resolution” or HiDPI. Thus, the text is four times sharper because it uses four times as many pixels to render text. With both these effects in place, I can get a 1280×720 “Retina” resolution on my old MacBook Air 11. If a monitor can’t display a stretched resolution, the best it can do for a HiDPI is half the resolution of the maximum native resolution. For example, this doesn’t do much of anything for my LG Ultrawide, which can’t display a stretched resolution. So results are entirely dependent on what SwitchResX can do with your display hardware.