You can specify exact font size using style sheets. The problem with style sheets is that the implementation in IE and Navigator are different enough to make it real hard to get a page looking the same in both. And if you want the page to also look good in older browsers, then the coding gets real fun.
Both IE and Navigator also supports some form of font downloading, although I've only have seen a single site that uses this technology so far (it IE wanted to keep on downloading the same font whenever I loaded a new page on the site).~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Thanks for the comments. I needed some back-up to respond to a designer who's telling me "Someone told me through a friend that they heard that you can do this..." - kind of thing. I agree that flexibility and accomodation of users prefs and requirements are of the highest importance. laura~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
You just want a genral *zoom* factor set by the user. The total relative sizes of the art remains the same only re-sized.
Code it to be a specific size, but that, at least on Windows machines, users can set their fonts to be larger or smaller so that we can't be 100% confident that the font will be rendered in the size we expect. As well as the fact that fonts render smaller on Macs than on Windows. Is there a way to absolutely fix a font size so that the user's browser preferences do not effect it?
There are some ways around it (using graphics is one), but it's really best to use a design that is flexible enough that the font size can get bigger or smaller. If a user has her font size set large, it may be because she can't see very well, and if you lock the font small, she may not be able to read it easily (or at all). At the very least, you are over-riding your reader's preferences, which (if they took the time to set them) they probably won't appreaciate.
Believe me, I'd love to lock everything down (I come from a print design background), and I have certainly been guilty of it in some of my own web designs, but the *best* thing for the web is flexibility. This is a medium for worrying about content and feeling of a page, not getting the x-height or leading you want.
As far as dynamic fonts go, check out Bitstream.com. It's a neat idea, but they take a long time to show up on your browser and do so in an odd manner. I know a year ago, there was buzz about them being a good thing, but I also seem to recall that Bitstream laid off some of its employees right after that.