Problems with font rendering on a MacBook Pro using external 24" LCD I have a 24" HP LP2475w at my home and 23" Apple Cinema Display at work. Today when I turned on my laptop at work, I noticed that all fonts look perfect (after having an issue with rendering for the past two days). I thought the issue somehow got fixed and happily went on with my day.

Later when I came home, everything still worked, because I didn't turn off my MacBook. This is how it looks (correct), even on my home LCD



but when I quit the Terminal.app (or any other app for that matter) and launch it again, while the 24" is still connected, the fonts get ugly



Notice even the background color is different, which doesn't make any sense at all, since the screenshots are taken about 15 seconds apart.

When I disconnect my LCD the Terminal still looks ugly, until I relaunch it, then it looks ok again.

The important thing here is, that I've been using the 24" LCD for the past year and never had this issue, it just started happening without me changing anything.

Is it possible, that my MacBook is somehow having trouble communicating with the LCD when the app starts? I would understand if this happened to everything that is displayed on the 24" LCD, but it happens only to apps that are launched when the LCD is connected.

Even if I quit all the windows in the terminal and open new ones it still looks ok, until I actually quit the application itself and relaunch it.
You should try adjusting font smoothing globally. Open up terminal and type:

defaults -currentHost read -globalDomain AppleFontSmoothing


Depending if it's enabled or not you might get a message such as: 

The domain/default pair of (kCFPreferencesAnyApplication,
 AppleFontSmoothing) does not exist


(which is actually good, since it tells us it's not set, and why you have the issue).

Next, type:

defaults -currentHost write -globalDomain AppleFontSmoothing -int 2


If it doesn't look any different, worse, etc. or want to adjust it even more replace the number '2' with '1'.

To remove the global setting you can use:

defaults -currentHost delete -globalDomain AppleFontSmoothing




*Hopefully this solves your troubles.