Typefaces changed from Calluna to Hoefler Text and Museo Sans to Tahoma.

And a great looking site… unless you’re on Windows. Unfortunately, Museo Sans isn’t well hinted and therefore renders badly with ClearType at medium to small sizes; it renders terribly with ClearType off and renders barely acceptably with IE9 DirectWrite. Looking at the design on Windows makes me suspect you designed it on a Mac? It looks lovely on a Mac and on Safari Windows (which uses the same text rendering engine as OS X).

Here’s a screenshot comparing Safari, Firefox (standard ClearType) and IE9 (DirectWrite).

http://i.imgur.com/l1Zb7.png

As you should be able to see, Safari looks best to us designers, but it’s renowned for rendering text fuzzily or heavily. The Firefox example doesn’t look great any way you look at it. Large type is clearly showing a lack of Y-axis anti-aliasing, and Museo has clumsy hinting. IE9′s DirectWrite text looks lovely at larger sizes – more delicate that Safari’s effort, but it still hints heavily at medium to small sizes and, as we’ve established, Museo is not well hinted and so it doesn’t look good.

There are several reasons Microsoft don’t take the Apple strategy, with one being that research has found well hinted text is more readable than unhinted text, given you have a font with good hinting built-in. Another reason is that people who are used to the ‘sharp’ nature of ClearType find OS X rendering ‘fuzzy’. I remember when my organisation turned on ClearType for the first time; they had so many complaints about fuzziness, they had to turn it back off again, much to my frustration. One person moaned, “I felt like I had something wrong with my glasses.”

I personally mostly prefer OS X and Safari rendering, but I’m a designer and I’m not working for my own pleasure. The way different systems render text is a constraint and I have to design around it. That means testing on Windows and making font choices accordingly.

But don’t take my word for it, he’s a great article on the subject that interviews some real experts:

http://readableweb.com/font-hinting-explained-by-a-font-design-master/

This topic of hinting might make a great RelPost, eh? Here’s another related article:

http://24ways.org/2009/real-fonts-and-rendering (the comments contain lots of good stuff – make sure you check those)