Whether you use Mojave or Catalina, Mac OS Still, those using external displays (particularly third-party displays) may want to select their resolution manually. Follow this article to learn how it’s done.
Setting custom resolutions for external displays in Mac OS
Here’s how you can override OS X’s limited, automatic suggestions and choose any supported resolution for your external monitor, a Philips FTV HDTV in this example.
- To change your Mac screen resolution, go toSystem Preferences > Displays. If you have more than one display connected to your Mac, a new Display preferences A window will appear toeachone. Select the window that resides on the screen you want to modify.
- By default, in recent versions of OS X, you’ll see a “default” recommended resolution for your external display. If you prefer a different screen size, OS X gives you four other options. Exact resolutions will vary depending on the specifications of your external display. Click on Scaly to see display options.
A real PC monitor usually displays a “Looks like #### x ####” resolution below the TV image in the options window.
On Phillips HDTV, OS
While suitable for most users, these five resolution options (default and scaled) are missing several “intermediate” display options, as well as “low resolution” modes, such as a true 2560×1440 which should be enhanced by the monitor and may be required for testing or software compatibility purposes.
Fortunately, these resolutions are still available and here’s how to access them.
- Press and hold theOption key on your keyboard and then click the Scaly option again.
- Once you’ve found your desired resolution, click its entry in the list to change your display.
- If you like a particular setting that fills the screen but cuts off the edges, slide the Underscan slider until it fits correctly in the viewing area. The previous Phillips TV required this step because the top and bottom areas could not be seen.
By following the steps above, the row of five recommended resolutions is replaced with a complete list of ALL supported resolutions. Those using a 4K display can also click Show low resolution modes to access the aforementioned low resolution options that will be enhanced through the device. If your Mac is connected to an HDTV, this list may also include refresh rates and alternative display modes if your hardware supports it. Everything you see is based on the TV or monitor model.
The interesting thing about Mac OS X is the previews you get when choosing a resolution using the Built-in Retina display option, found in the Optimize for section.
When you hover over the resolution thumbnails within the scaled settings, the system allows you to see what a window will look like under that particular setting.
While your resolution options will survive reboots, the list of “all supported” resolutions described above is not always visible. OS X will return to default view after closing and reopening System preferences. Just remember to click Scaly while holding theOption keyand you will see all supported resolutions again.
Custom external display resolution
Customizing your external display in Mac OS X is a simple process once you know where to adjust the settings. If the default options don’t work for your external display, you will most likely need to use the low resolution modes.
