After installing Snow Leopard on my 15″ MacBook Pro a few days ago I noticed that fonts, specifically at low sizes, looked terrible. Edges where overly rugged and text seemed dim. In essence, it seemed as if every font had decreased an entire weight.

With further research I discovered that this is a problem with 3rd party (non-apple) monitors and their default status in 10.6. Previously in 10.5’s System Preferences users where able to alter Font Smoothing with one of several options:

Yet, in 10.6 the option has been replaced with a simple Use LCD Font Smoothing When Available dialogue. The problem is OS X 10.6 detects some 3rd party monitors (Dell, Samsung, Lenovo, etc.) as CRTs and doesn’t allow them to utilize font smoothing. Here’s an example side by side of font non-smoothing vs. smoothing on Snow Leopard.

Fortunately there is a way to force font smoothing via terminal, simply paste the following text and hit enter:

defaults -currentHost write -globalDomain AppleFontSmoothing -int 2

• 0 – is the setting for CRT rendering (looks horrible on LCD)
• 1 – is the setting for Light
• 2 – is the setting for Medium (Best for Flat Panel)
• 3 – is the setting for Strong

Once you’ve set this you will want to log out and back into OS X. At this point all the fonts should look as they did before your upgrade to 10.6. Hoorah!

Update: Added another example from iTunes music selection that highlights this issue a bit more. Also, updated a grammar fix thanks to Reddit user guriboysf.