External monitor = blurry fonts

Possible resolution for some users:

I running Lion on my MBP and have run into the same issue described here with an external Samsung monitor.

Adapter is a thunderbolt-HDMI (I did not have an issue with the thunderbolt-DVI)

To resolve the blurry font issue I had to change the video mode from 1080p to the max available resolution setting which for me was 1680 x 1050 (60Hz)

I know this isn't ideal but it fixes the blurry text issue nicely.

Thank you for the ireckon link. It worked for me using a ViewSonic external monitor.

HOWEVER......THERE IS ONE ADDITIONAL STEP

Be SURE that your external monitor's input is set to "PC" rather than "AV". I am using a thuderbolt to HDMI adaptor to connect to my monitor's HDMI input. The default setting for this is "AV" by which I think treats the signal as a TV 1080p resolution rather than a monitor 1920x 1080. Even after forcing the MAC to send a RGB signal, the text remained blurry until I switched the input to PC.

Also, make sure that the monitor display is set to RGB rather than YUV mode (TV mode).

Hope that helps somebody.

And again, the question remains: Why does Apple Central make it so difficult to play nicely in the sandbox with non-Apple products.......

Thank you for the ireckon link. It worked for me using a ViewSonic external monitor.

HOWEVER......THERE IS ONE ADDITIONAL STEP

Be SURE that your external monitor's input is set to "PC" rather than "AV". I am using a thuderbolt to HDMI adaptor to connect to my monitor's HDMI input. The default setting for this is "AV" by which I think treats the signal as a TV 1080p resolution rather than a monitor 1920x 1080. Even after forcing the MAC to send a RGB signal, the text remained blurry until I switched the input to PC.

Also, make sure that the monitor display is set to RGB rather than YUV mode (TV mode).

Hope that helps somebody.

And again, the question remains: Why does Apple Central make it so difficult to play nicely in the sandbox with non-Apple products.......

***Update*** In addition to executing

defaults -currentHost write -globalDomain AppleFontSmoothing -int 2

The final step for my configuration was "Overscanning". I had to set overscanning to none in the Apple Display preferences then go through the menu settings on my monitor and set overscanning to "off". After the two software and one hardware adjustments the external display is quite crisp and exactly what I would expect from a high dollar external display.

Horray! I found a solution.

I bought the Apple Mini DisplayPort to DVI converter cable adapter instead of using HDMI, and my picture is much more crisp and clear.

My Retina display is still better, but it's a better screen. my HP monitor is now performing to is ability. For some reason, HDMI must degrade the video quality.

I had the same problem extending my desktop to a a good quality monitor and switching the generic HDMI cable with a good quality HDMI to DVI cable by (Pure AV) fixed the issue!

My conclusion:

Buy a good quality cable & you will be amazed with the difference. 🙂

Enjoy!

Sorry, but I have to disagree. With today's digital communications, one HDMI cable is as good an any other. Paying more might get you better construction, but not signal quality.

It's not about the cable. It's about OS X thinking whatever is connected through HDMI must be a television set and if it's DVI (even through a HDMI->DVI cable) it must be a computer monitor (resulting into a sharp output in the RGB color space). Now I can somehow understand that (but I really have to try hard), but the fact it treats DisplayPort the same way (unless it's an Apple Cinema Display of course) is not acceptable. At least the workaround still works with Mavericks...

You must be right. I noticed the monitor was identified by OS & automatically switched to it's color profile.

The color profile that I created previously by calibration still showed more accurate colors & better than the HDMI-to-HDMI cable unless my eyes are deceiving me.

I didn't know that so I did a quick search. My understanding is quality doesn't matter in most cases however in some cases it will. I think it's worth to think if the cheapest cable was purchased.

If you can elaborate on "better construction" I would appreciate it.

I wrote a blog post about the two solutions we tried at our company to fix this, you could try them, they should help:

Fix-Blurry-weird-text-and-picture-quality-when-connecting-Mac-to-external-Monito r-via-external-Displayport-HDMI-forcing-RGB-mode-instead-of-YCbCr-Override-Edid- Dell-U2713H-Dell-U2713HM

Switching to DVI (using that mini display port -> DVI adapter) worked for me too! Fonts looked terrible when I connected both of my monitors to my new 15" MacBook Pro via HDMI, but when I bought that adapter and used a DVI cable, the problem was solved. First I tried the various other solutions posted in this and other threads (downloading and running a script etc.)

Chris

This problem is mostly not cable related, particularly for me. I am using dual screens into my retina MBP. One is HDMI to thunderbolt and the other is DVI to Thunderbolt. The problem is very noticable fuzzy fonts (very depressing). If I have Windows in Parallels open on either of the monitors then I have absolutely no issues with font rendering. So there's definitely an issue with the OS X setup. (Same goes for if I load up Linux in the VM, fonts look great)

If you're using an HDMI connection to a monitor then that HDMI fix for using RGB and telling OS X the monitor is a PC monitor and not a TV really well but the font issue is only improved on, not fixed.

Indeede.

I have the same situation. You described it accurately. I have tried the scripts as well as the fixes posted by Amthenia. OSX fonts are still fuzzy and unacceptable.

I find it very frustrating that Apple hasn't fixed this (and over a year has gone by), yet when I run Windows in Parallels or VMWare's Fusion, the Windows system doesn't have this problem? Weird.

It's hard to believe that in this age of HDMI and Thunderbolt, Apple still has trouble handling external displays. This one is a deal breaker.