Font rendering in OS X

Thanks for the answer.

My fonts are ok I think. It's the font rendering that simply is not optimal for the external LCD. The fonts look ok on the internal display. It doesn't matter which font I select in Mail (in font settings) - every font is "over-smoothed" and looks "edged" and slushy.

What I do not understand is the fact that especially the Finder seems to do a completely different font rendering. If you have the possibility, please compare the characters in Finder with the same characters in Mail. I am quite sure that you will realize the same big difference.

I now made two screenshots of Mail: The first one while the external display was disconnected, the second one when it was connected (and Mail moved to the external display). I opened both screenshots in Photoshop and there was a clear difference between the font renderings: On the screenshot of the internal display, the fonts are smoothed with black and grey pixels only, while on the screenshot from the external display they are smoothed with colored pixels. This is the reason why the text looks so bad on the external one. Therefore, it is definitely a problem of the font rendering. In Photoshop, the difference of font rendering is clearly visible!

See here:

http://img208.imageshack.us/img208/5389/fontt.jpg

The first line is internal display, the second line external display. That's unbelievable.

Another thing: I found out that it's not only Mail that has the problem - it is any application that was started after the external display had been connected. It seems that OS X applies the font rendering setting at the moment a application is starts. When I disconnect the display, start Finder, Mail, Safari and so on, and then connect the display, then all the applications look great even on the external display. When I quit the apps and then restart, the font rendering is broken again

Thanks for your further answers.

I double checked with my other (new) MacBook (15" Unibody). The font rendering on the external 24" monitor is exactly the same, it looks very blurry and text can hardly be read. And be sure: I use the native resolution and even tried to calibrate the display with Apple's calibrating tool in system settings. The used profile is the right one, it is named like the monitor model. The same for the internal display: It uses Apple's own LCD profile.
I also started Windows 7 in VMWare and the result was a pretty good picture with perfect font rendering on the external monitor. Therefore I am sure that there is a problem with the font rendering setting in OS X.

The interesting thing is that the picture of the internal display of the 15" MBP looks great, although it is using the colored subpixels as well. I don't think that the colors make any disadvantage ingeneral, but it seems that the kind of font rendering is simply wrong for the external 24" monitor on both MacBooks. I think that OS X for sure does adapt the font rendering dependent on the monitor profile. What I would need is the possibility to change the kind of font rendering manually.

Tomorrow I will try to use another profile that OS X offers. Maybe this safes the problem.

It's a new Fujitsu Siemens 24" 1920*1200. Don't know the exact model number, but it is a business display - has not the best color quality. But with windows (even in VMWare), the font rendering is perfect. And as already mentioned, when I start an application in OS X before I connect the display, then the fonts are also rendered perfectly. OS X changes the font rendering especially for the display and I don't know how I can come around this annoying problem.

At first I have to correct my post above: I was wrong with the pictures: the first line (with the grey subpixels) was the external monitor, and the second line with the colored subpixels was the internal one. I have access to the monitor again tomorrow, so I can do a final check not until this time. But I already compared what happens to the font rendering on my internal display when I enable and disable the "LCD font rendering" in System Preferences: Indeed, when I deselect the LCD rendering, the fonts have grey subpixels, and the text looks similar blurry than the picture on my external display (although it's not that bad, but this may be due to the big screen and maybe the matt surface of the Fujitsu display). LCD enabled brings colored subpixels for my internal display. On the external display, the rendering was grey although LCD rendering was selected. Therefore I am sure that this will solve the problem. Will see tomorrow and let you know! Thanks a lot!

One question: Is this a permanent setting? If yes, how can I undo this setting?

MarioGrgic,

thanks a lot for your help. I tried the external monitor again and the picture is great. Yes, that solved it.