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At home, I have a 4K monitor with 3840x2160 which I use at 100% scaling. At work, I have a 2560x1440 LS27A600N screen which is the same physical size, but the windows and text are annoyingly huge because the fewer pixels are larger.

I want macOS to drive the 1440p screen at full resolution but to apply a 66% scaling to the desktop, making it mimic the 4K 2160p screen: text and the window borders appear the same physical size as on the 2160p 100% scaled screen, though blockier - something both Linux and Windows can both do trivially. (And Apple Remote Desktop, ironically.)

Summary as of Ventura: macOS appears incapable of scaling the local desktop down from 100% on external screens, to let them fit more text without messing with the application settings, and there are no third-party tools to do it.

Side note - the inbuilt laptop screen displays at 200% scaling: it could in principle display 4x the information, but Apple doesn't care that you might want to do that either.


Earlier stuff, not so relevant now:

It's not about resolutions as such, it's about the visual font size and window decorations: I have 'more space' set for both the 4K and the internal screen. I want similar default font and window decoration physical sizes as I get on the 4K screen appearing on the 2560x1440 screen, even if that means the letters are a bit blocky or more obviously anti-aliased.

If I maximise my terminal window on my 4K, I get 545x143 and the scroll bar and title bar are about 2 characters high/wide (obviously, I rarely use it that large!). If I drag the terminal window to the built-in screen, the font is... basically the same, a bit bigger. On the 2560 screen, it feels like the letters are nearly twice the physical size of the 4K ones in the real world as measured in actual cm or inches, not just relative to the size of the screen.

If I set 'default for display' scaling for the 4K screen my terminal window gets a laughable 268x72 characters for the same font setting (Andale Mono 12).

So it seems I want 'even more space' or 'stupidly much space' for the 2560x1440 screen (and ideally the internal screen), but Apple won't provide that. Ideally, I'd be able to tell it 'effective resolution' (4K or better) and have it scale that down to the native screen resolution.

Unfortunately (for the question, fortunately for me) I'm in Berwick for about a month, so I don't have access to the 2560 screen. I'll see if I can borrow one.

On the Samsung LS27a600n 2560x1440 at work, the Andale Mono 12 gives a terminal of 362x96 characters. I can obviously get 545x143 if I reduce the font size for the terminal, but - as I say - the point is that I want this effective scaling for everything on the screen, so Andale Mono 12 would give a damn good approximation to 545x143 and all the other applications (Slack, Chrome, etc) and window boundary controls would be similarly scaled.

I've updated to Ventura and there is still no option to scale the graphics to 66% on the screen, to make 1440p behave like a slightly fuzzy 2160p screen. Linux can do it, Windows can do it. Apple - incapable.

I found Display Override PropertyList File Parser and Generator with HiDPI support which purports to let me overscale the screen, but it's not for 12.6.1 and things are in different places - UID and PID - and in particular there's no key to enable HiDPI (which I presume is significant)

I tried it and used the suggested command-line tool (since I can inspect it for security) but no dice - it looks like it's ignoring the new plist (which has 9 settings) and the resolution changer shows something like 40.

I thought I'd ask in case there's something more official (or in case someone else needs the reference).

I don't care about fonts looking a bit crappy, I care about the effective display size.

Update: 12.6.1 (21G217)

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  • What Mac and OS version is this?
    – benwiggy
    Jul 3, 2023 at 8:58
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    I'm slightly puzzled by it being 'annoyingly huge'. 2560x1440 on a 27" screen is very much a 'standard resolution' used by many, since long before HiDPI/Retina came along… in fact I'm looking at 2 of them right now. They're the 'perfect' resolution at defaults. Are you certain what you're actually seeing is a true 2560x1440? [The Mac shouldn't consider the screen to be HiDPI… because it isn't one.] 1920x1080 I'd consider 'too big' on a 27" screen, more useful on a 24". [reposted to fix significant typo]
    – Tetsujin
    Jul 3, 2023 at 10:00
  • A test. Screenshot of my entire desktop at actual size 2560x1440 (no state secrets visible;) including Safari open to this page. If you open it in Preview, then hit Cmd/0 [zero] that should expand it to the correct size, but because of the window borders will not quite fit the screen. If you then switch to fullscreen, it should fit perfectly without changing zoom at all.
    – Tetsujin
    Jul 3, 2023 at 10:10
  • Check out github.com/waydabber/BetterDisplay and see if that offers a combination that suits you. There's plenty of functionality without paying up... Jul 3, 2023 at 14:14
  • @Tetsujin It's not the resolution as such, it's the font size and window decorations. I'll update above. Aug 7, 2023 at 12:07

3 Answers 3

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I presume (though you should check) that your 4K display is using a default scaling factor of 2x. In other words, it's scaling things as if they were a 1920 x 1080 display at 27 inches.

If you match the 'virtual' resolution, then you should get things the same physical size. E.g. select a scaled resolution of 1920 x 1080, or as close as possible.

System Settings (Preferences as was) > Displays should show you a list of available resolutions.

In Ventura, if System Settings > Displays does not show a list of resolution sizes, it should still give you scaling options, and you can see the resolution when you mouse over. Alternatively, you can click on Advanced..., and switch on "Show resolutions as list".

In earlier OS versions, you may need to click on a radio button that says "show all scalings" or similar, or hold Option while you click on the button that brings up the sizes.

Note that you're not making your 2K monitor 'pretend to be 4K': you're just matching the scaled resolution size. Your 4K display is scaling at 2 times; and your 2K display is scaling at 1.333 to get the same size.

Also note that if the displays were different physical sizes, there would be further calculations required to get objects displaying at a similar 'size' on both displays.

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  • I have my 4K and internal display (and the 2560 screen when I'm in London) set to 'more space', so I would hope it's 1:1 scaling. Settings> Displays> Display Settings> doesn't show me resolutions at all: it shows me 'Use as: extended display' 'Resolution: Default for display / Scaled' and 'Larger Text ... More Space', then colour profile, refresh rate, and rotation. Nothing useful. Aug 7, 2023 at 12:57
  • @TimBaverstock As in my answer, you should be able to get a list of scalings instead of the "Larger/More Space" buttons. I doubt that More Space is 1:1.
    – benwiggy
    Aug 7, 2023 at 13:35
  • Having upgraded to Ventura (I can't upgrade to Sonoma because it breaks Apple's own XCode over VPN) I see 2560x1440 in the resolutions list for this screen, but it neither lists 3840x2160 and nor offers 66% scaling. In principle, this computer could impose a scaling factor of 66% on this display so Andale Mono 12 would display as if it were Andale Mono 8, and the screen-top menu bar and window title bars would be 54 pixels instead of 80-odd pixels high, etc. Linux and Windows can do this trivially. Windows even makes it easy and warns you that things might look fuzzy. Apple... fails. Nov 13, 2023 at 18:59
  • Taking a screen grab with GIMP of the work screen, I get an image with 2560x1440 pixels - that's 100% scaling. The inbuilt display results in an image of 4112x2658 which means 200% scaling even at 'more space'. I'm pretty sure that the 4k at home will give me 3840x2160 because it's certainly not scaling things to 200% because that would make its text even larger than the 1440p screen. Apple has such a bad attitude to its users. Nov 13, 2023 at 19:16
  • Yup - 3840x2160 sized screengrab. Nov 14, 2023 at 9:18
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A 27” iMac has 5120x2880 pixels displayed as 2560x1440 points. It seems you have a 2560x1440 monitor. To get the exact same window and font size as on that iMac, go to settings, display, pick “show all resolutions” and pick 2560x1440. Obviously it’s not a Retina display, you’d have to pay major money for that.

Your 4K, 3840x2160 monitor, is probably displaying as retina 1920x1080 pixels. On your works Mac you should be able to pick the same 1920x1080 pixels. Alternatively you can switch both monitors to 2560x1440. Whatever you prefer.

Remember: Look for the checkbox “Show all resolutions”.

About resolutions: You have hardware which is 2560x1440 or 3840x2160 pixels. And you set a point size for the monitor, say 1920 x 1080. The software will decide whether it uses Retina mode or not. In Retina mode, it will create a buffer of 3840 x 2160 pixels (twice the resolution that you picked) and scale this to your monitor pixels. In non-retina mode, it will create a buffer 1920 x 1080 pixels to draw into, and also scale it to the monitor to display. All the software on your Mac will think it has a 3840x2160 pixel monitor in Retina mode, or a 1920x1080 pixel monitor in non-retina mode, it cannot find the actual number of pixels on your screen, and it cannot find your screen size (like 21" or 50").

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  • My home 'extended display' screen has a resolution of 3840x2160, known as 4k from 3840 being nearly 4000. Even with 'Show all resolutions', the mac does not offer anything higher than that. As I write in the accepted answer, if I plug in a larger dummy screen - at home, I have a 5k dummy 5120x2880 - I can make the 4k mirror that dummy screen and get a slightly fuzzy 5k information density on the 4k screen. MacOS COULD do this in software, but does not. Feb 12 at 11:05
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This suggestion was made to me by https://www.madrau.com/ and I've confirmed it works (for real screens, anyway).

Plug in a 4K dummy screen dongle (£3 on eBay) and tell the 1440p screen to mirror the dummy screen.

That's it.

Something that could trivially be done in software.

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