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Jagged text (no font smoothing) on Dell U2520D monitor with macOS

R

ralphch

macrumors newbie
Original poster
Nov 20, 2012
26
5
Hi all,

I just purchased a 25" Dell U2520D monitor (resolution 2560x1440), which is Rtings current top recommendation in this size category, and text looks very jagged in macOS, almost lacking entirely in font smoothing/antialiasing. This is especially noticeable in all system dialogs and text that is smaller in size -- text inside applications seems slightly better.

I tried connecting other Mac computers to the monitor, and they're all the same. I tried different cables (USB-C to USB-C, USB-C to DisplayPort), and no changes. I spent hours scouring the web, trying different settings in Terminal to no avail. Color profile is set up correctly to RGB in the monitor. I also tried sharpness controls in the display itself and that doesn't do anything -- it just makes text blurry.

I connected a Windows computer and fonts appear slightly better (acceptable), not as jagged as macOS, but not perfectly smooth either (maybe because all system fonts in Windows are slightly larger?)

This is how fonts appear in my external display:

01.png

02.png

03.png



If I turn on font smoothing, it actually makes it much worse, which is the opposite of what every article on the web recommends...

04.png



It's quite bizarre that turning on font smoothing settings in macOS makes this a lot worse. In fact, if I change my desktop background to black and look at any OS menu, text appears extremely horrid, like this:

05.png


Setting macOS to Dark Mode is even worse, completely unusable. Some examples:
06.png

07.png




This is a brand new monitor model, highly ranked by all the review site.

I suspect lots of Mac users are considering/buying the Dell U2520D, since it's a the top of lists online and Dell displays are a popular choice for Mac users.

I have another older Dell P2715Q 4k display, and while obviously I'm not expecting retina quality on this new non-4k display, it's quite frustrating to see such jagged text.

Does anyone know what might be happening here, and any ideas on what to do about it? Should I be looking for a different monitor? Or is what I'm seeing expected? Did I get a lemon of a monitor from Dell?

Any help/ideas is greatly appreciated.
 
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I agree - the various changes that you showed (font smoothing, black, white), show little to no change at all on my end.
I think that is because you have posted screenshots, and not pictures of the actual screen that you see.
(screenshots use the quality of the viewer's video, and NOT the creator's (your own) perceived video. Pictures will show, well, pictures of what YOU see.)
 
Hi @HenryAZ and @DeltaMac, thanks for your replies.

Are you looking at my screenshots on a retina display? Because I can see some differences; the text is lacking antialiasing in some parts. I tried to take pictures of the screen itself, but it's very difficult to capture what I actually see.

Here's the weather notifications in dark mode, taking a picture with my iPhone:

IMG_2414.jpg



Even this picture does not do justice to what I'm actually seeing. The small text "Sunny currently..." actually looks very jagged in person, like entirely lacking antialisiang. While the larger text above ("July 19") is smooth.

The problems are especially noticeable on very small text that is either pure black (in light mode) or pure white (in dark mode) and has medium to bold weight. Any characters that have diagonals (e.g. / , W, V, M, etc) are especially bad.

Maybe I'm just used to looking at 4k/retina panels for too long and this is expected for a 1440p monitor?

But I thought antialiasing worked better than this...
 
mj_ said:
This is why, and that's what I keep telling people. LowDPI screens will look like hot garbage once you gut used to HiDPI resolutions.
Click to expand...

frou said:
Apple removed sub-pixel font rendering in Mojave (10.14) and so macOS on LowDPI monitors now looks worse than it used to.
Click to expand...

Great points, this really explains everything. LowDPI is difficult to look at coming from HiDPI, and then Apple made it even worse by removing sub-pixel font rendering.

And it also explains why, by comparison, Windows doesn't look as bad -- it's actually quite decent.

So I guess I have to consider this "case closed", it's doing what it's supposed to do under the circumstances, and I just have to get used to it or get a HiDPI screen.

It really makes me wonder why Dell didn't make the U2520D 4k when the 27" version is (U2720Q), and they have much older 24" that was 4k (P2415P). Seems like pure cost-cutting/profit maximization to me... If it wasn't for this one shortcoming, the U2520D would be a perfect monitor for anyone with limited desk space.
 
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ralphch said:
It really makes me wonder why Dell didn't make the U2520D 4k when the 27" version is (U2720Q), and they have much older 24" that was 4k (P2415P). Seems like pure cost-cutting/profit maximization to me... If it wasn't for this one shortcoming, the U2520D would be a perfect monitor for anyone with limited desk space.
Click to expand...
Probably because 25" sits right in-between that odd space between a space-saving 24" and a spacious 27" display, and nobody bothers making 25" panels anymore ;)

My suggestion: return the U2520D if you still can and get a decent 27" 4K display. Doesn't have to be Dell, LG makes brilliant ones too.
 

The subpixel-AA debacle and font rendering

Since the disablement of subpixel anti-aliasing by default in Mojave, many folks (including myself) have noticed that some applications render fonts strangely on non-Retina displays. I notice this especially in Marzipan apps like News and Stocks. Are things better in Catalina? What's the state...
forums.macrumors.com forums.macrumors.com

Worth reading, maybe you can find a setting you like. I'd probably just add a 2560x1440 HiDPI mode and use that.

Alternatively, return the monitor and get a P2415Q (or other ~24" 4K) so you can actually run it in HiDPI.
 
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Hi. I have a Dell U2515H, basically a previous generation of your monitor, and under Catalina I have got fonts to look fairly decent. Not as good as subpixel AA but still pleasant to look at. A few points:

  • Have you enabled supersampling? If you go to System Report > Graphics you can see what your framebuffer resolution is. This should be twice your screen resolution. In Big Sur this is automatic, but in Catalina you need to do this: https://comsysto.github.io/Display-...or-with-HiDPI-Support-For-Scaled-Resolutions/
  • After supersampling is on, try running at a lower virtual resolution. This should make everything a bit sharper. Instead of running native 2560x1440 I created a 2048x1536 mode which is perfect. (Remember to add this as 4096x3072 in the link above). You need to use SwitchResX or RDM to switch to your newly created resolution. [Note this isn't really a lower physical resolution as your graphics card still sends 2560x1440 pixels to your monitor]
  • Finally turn font smoothing on in preferences, and then run this terminal command: defaults -currentHost write -globalDomain AppleFontSmoothing -int 1 to make the smoothing effect light rather than heavy. Log out and log in again to see the difference. See here: https://colinstodd.com/posts/tech/fix-macos-catalina-fonts-after-upgrade.html
Hopefully that should improve things?
 
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Sorry I mean 2048x1152.

Remember that's not a physical resolution. It's just the "looks like" resolution in the system report. The screen still receives the full 2560x1440 pixels.
 
tornado99 said:
Sorry I mean 2048x1152.
Click to expand...
Yeah, that's more like it. :)

tornado99 said:
Remember that's not a physical resolution. It's just the "looks like" resolution in the system report. The screen still receives the full 2560x1440 pixels.
Click to expand...
Running at "looks like 2048×1152" draws everything on a 4096×2304 frame buffer which is scaled down to the screen's resolution (to 2560×1440 in your case).
 
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For anyone having this problem, I found a fix not mentioned above, and created an account just to share this. I got a new monitor, and the fonts were displaying jagged on it, and I couldn't figure it out. Tried the solution that forces RGB, and no dice. I finally talked to my dad who's a video engineer, and he told me to try adjusting the phase on the monitor (in the monitor menu) and it worked like a charm. There's a sweet spot in the middle – not too high, not too low – that gets the fonts nice looking again. Figured I'd save someone else the hours of researching and trying different things I did. Best of luck.
 
MrMoodle said:
For anyone having this problem, I found a fix not mentioned above, and created an account just to share this. I got a new monitor, and the fonts were displaying jagged on it, and I couldn't figure it out. Tried the solution that forces RGB, and no dice. I finally talked to my dad who's a video engineer, and he told me to try adjusting the phase on the monitor (in the monitor menu) and it worked like a charm. There's a sweet spot in the middle – not too high, not too low – that gets the fonts nice looking again. Figured I'd save someone else the hours of researching and trying different things I did. Best of luck.
Click to expand...
Hi there! What do you mean "phase on the monitor"?
 
MrMoodle said:
On my monitor the option to adjust the phase was only available via a VGA connection
Click to expand...
This is because the phase only needs to be adjusted when using an analog connection in the first place. No need to when using a digital connection.
 
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Amethyst1 said:
This is because the phase only needs to be adjusted when using an analog connection in the first place. No need to when using a digital connection.
Click to expand...
Yeah, that's the general idea. But unfortunately, with my computer/graphics card it was displaying the text as jagged/out of phase with an HDMI connection, which is why I had to go back to a VGA connection in order to adjust phase, which fixed the problem for me.
 
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