text sizes: by percentage, pixel, point, other?

Is there a prefered method for sizing?

[liza]

Would appreciate some thoughts on the best way to specify text sizes. I've read some arguments against pixels and points, so I've stuck to percentages. Anything I should know about?

If I do use percentages, how big does it have to be to be readable? I'm using Verdana at 70% for my main text. I arrived at this number by trial and error based on what seemed to look good. The only potential problem I can think of is that if somebody doesn't have Verdana installed and it instead gets displayed in Helvetica (the "second choice" font I specified), it would look quite a bit smaller than in the first font.

[jo1ene]

I use em. I would suggest that your first and second choices render simlarly. I would also venture a guess that people who have difficulty seeing already know where the text zoom, or whatever is on their browser. Maybe not, but don't obsess over it. Just be consistent.

[drbrain]

For screen layout, I prefer to use em for units as much as possible (including positioning, margin, padding and border). For print layout I use points.

[ergophobe]

people who have difficulty seeing already know where the text zoom, or whatever is on their browser

Unless you use px sizing, which does not resize in IE. I use em or % for screen layout, but the key thing is to make sure that you use a method that can be resized in IE by the user.

Tom