Font sizing trouble

It’s pretty well known that when specifying font sizes, it’s good to use a relative unit like em or percent, since the dinosaur browser MostPeople™ use will not let you resize text when size is specified in pixels.

Some will say that they don’t care if the text on their website is resizable or not, since their target audience does not include those with poor vision. Some would even like to be able to disable font resizing in all browsers, since they feel that they know better than those visiting their site what font size looks best and is most readable.

Well, I have perfect eyesight and still like to increase the text size for many sites. I do this so I won’t have to squint when reading the text, and to be able to keep my face at least a healthy arm’s length away from my screen. Since I use Mozilla most of the time, I can resize the text of all websites, no matter what unit is used to specify font size, but all those poor people that for one reason or another stick with their old IE/Win can’t. That’s why I use ems to specify font-size here.

So what made me write about this then? Dave Shea’s post Font Size: No Happy Medium and the followup Font Size Redux did. Interesting posts, with interesting discussions going on in the comments. Anyway, I’m happy that Dave added a style sheet switcher to Mezzoblue so I won’t have to hit Command + ‘+’ every time I visit his site anymore ;)

Posted on November 29, 2003 in CSS, Usability


  1. The thing I haven’t been able to understand in all of this is that my default font size is pretty much the same as a lot of other common sites. I mentioned it a few times, but it seemed to get glossed over. Maybe you can shed some light, Roger - is the CTRL ‘+’ thing a common occurance on a lot of other sites? I think mine was just a target since the discussion was open anyway, but I’m pretty sure I’m not the only one in the world using that font size…

  2. November 30, 2003 by Roger (Author comment)

    I went through my bookmarks and noted which sites I find hard to read unless I increase the text size, hoping to find what they have in common. Most of the blogs I read are no problem. Small text is much more common on corporate sites and discussion forums. It seems like it’s a combination of many things: font size, line height, font colour, background colour, typeface and the way Mac OS X renders text. For the record I’m using a 21” CRT monitor set to a resolution of 1600 by 1200 pixels. Text that is smoothed by the OS is easier for me to read at smaller sizes. I have my threshold for text smoothing set to 10 pixels, which I believe is the default for Mac OS X. I tried changing the text smoothing threshold to 8 pixels. That made quite some difference. Mezzoblue is now much easier to read. The drawback is that text in the user interface elements of some applications will also be smoothed. Single words are easier to read when the text isn’t smoothed. Whole paragraphs of text benefit from smoothing. So if you specify a text size small enough to fall below the threshold for font smoothing, some people may find your text harder to read (depending on their OS, text smoothing settings and personal preferences). I don’t think there’s much you can do about that, other than do what you already have: make the text resizable and have a style switcher to give your visitors a choice. Good enough for me :)

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