Enable Better Font Smoothing on Some LCD Displays
One of the unwelcome changes in Snow Leopard, at least for myself and others who use certain third-party LCD displays, was the gross simplification of the font smoothing options in the Appearance System Preferences panel.
In OS X 10.5, a pop-up menu provided a number of options for font smoothing--automatic, standard, light, medium ("best for LCD"), and strong.
In 10.6, though, that's been simplified down to simply a yes or no option: "Use LCD font smoothing when available." I guess the thinking here is that CRTs are a thing of the past, and all LCDs feature intelligent font smoothing.
In practice, however, that's not the case. For me, the problematic machine is my OS X-running Dell Mini 10v netbook.
For me, the problem was that the text on the Dell was really "light" and hard to read after upgrading to 10.6. This made it tougher to read, and led to eyestrain if I used the machine for an extended period of time.
Lest you think this issue is restricted to those running homebrew netbook Macs, however, that's not true--apparently standalone LCD displays by Dell, Samsung, LG, HP, EIZO, Lenovo, and possibly others are affected as well.
Thanks to Mac OS X Hints contributor astrosmash, however, my netbook is back to its pre-10.6 smoothing settings.
Before I get to the solution, though, here's an example from a document in TextEdit on my Dell. The top portion of the image is how the document appeared prior to applying the fix; the bottom was taken after I applied the fix.
The image below is small and somewhat fuzzy; just click on it for a larger (and much clearer!) version of the image. (The larger image really makes the differences apparent.)
Font smoothing on a Dell LCD before (top) and after (bottom) a Terminal fix in 10.6.2 (click for larger, clearer image)
Notice how the top image is quite light--dots on "i" characters are hard to see, and the text has an overall gray tinge to it. In the bottom image, the gray is gone, and everything is a bit bolder while still being clear and crisp.
By zooming in a bit, it's easy to see the difference between the before and after images.
The top portion of the image at right is before the fix; notice that the font smoothing is done completely with levels of gray.
In the bottom portion of the image, taken after the fix, you can see not only more levels of gray, but the subtle use of some colored pixels to smooth the font--there's a yellow pixel on the left edge of the dot on the "i," for example.
If you've got an LCD panel that you think looks worse than it did before upgrading to 10.6, you can try this fix to see if it makes things better. How? Just open Terminal (in Applications -> Utilities) and paste this command, then press Return:
defaults -currentHost write -globalDomain AppleFontSmoothing -int 2
The 2 at the end is equivalent to the old "Medium - Best for flat panel" setting in 10.5. You can also use 1 for light smoothing, and 3 for strong smoothing. This change will only affect newly-opened applications--anything already running will have to be restarted to see the affect of the changes. As such, you may want to experiment with a document in Text Edit, trying the three alternatives, and then after you find the one you like best, rebooting your Mac (so that it will take effect system wide).
Note that if you go back into the Appearance panel and toggle the font smoothing setting, you will override your manually-set value--so don't do that if you value your newly-smoothed fonts.