ClearType: Love It or Leave It
Vista will have ClearType on by default. IE7, until the latest beta, automatically turned on ClearType for all IE7-displayed content. And now, Office 2007 will also turn on ClearType:
If you are running on Office on Windows XP or Windows Server 2003, Office text is rendered with ClearType regardless of the system setting. This is because all of the Office fonts have been optimized to run in ClearType but most people don't know about the setting in the OS. If you don't wish to use ClearType, you can turn it off here and Office will follow the system setting. If you are running Windows Vista, Office will always follow the system setting.
I like ClearType-- it increases the effective horizontal resolution of computer displays by 3x:
It does this by leveraging the arrangement of RGB subelements in a LCD display. It's basically "colorized" antialiasing:
Looks crazy, but you have to see it in context on a LCD panel to understand where those extra pixels are coming from:
All the new Vista fonts are drawn with ClearType in mind.
The new fonts are hinted to produce optimal results if, and only if, ClearType is enabled. Unfortunately, this also means that the Vista fonts look truly awful with ClearType turned off. It's looking more and more like I better love ClearType!
I don't mean to sound ungrateful, because there is at east one set of experimental evidence that proves ClearType is more legible:
Overall, the study participants read the ClearType sentences statistically reliably faster than the sentences rendered in black & white (called aliased here). The magnitude of effect is approximately 5%. From the figure it’s clear that while ClearType improves both italic and normal (Roman), ClearType has a larger improvement on the italic text.
Although ClearType has "clearly" won the war, there are still a few edge conditions where ClearType doesn't look good:
- ClearType assumes a specific arrangement of RGB elements in an LCD screen. Fortunately, CRTs are pretty much dead; so most computer displays are now LCD by default these days. However, if your LCD supports rotation, eg, can be used in both horizontal and vertical orientations, ClearType will only work in the horizontal mode.
- ClearType is most effective when the text in question is black on white or white on black. Other colors work, but aren't quite as effective, because they interfere with the entire range of RGB colors available for the "colorized" hinted pixels.
- ClearType is particularly effective on small fonts, but not so much on large fonts. On small fonts, traditional black and white antialiasing is too granular and produces fuzzy results. That's why standard Font Smoothing only "kicks in" for fonts above a certain size. ClearType, because it actually increases resolution, can be used on small fonts. However, for larger fonts, the difference between ClearType and standard Font Smoothing is marginal.
Some other resources on ClearType:
Sub-Pixel Font Rendering Technology
ClearType, CoolType: The Eyes Have It
Wikipedia entry on ClearType