John Smith's Blog

Ramblings (mostly) about technical stuff

Helvetica is dangerous

Posted by John Smith on

For the past couple of months or so, I've been using the "Minefield" nightly builds of Firefox 4.0 rather than the "official" 3.6.x releases - 4.0 truly is an upgrade that merits the increment of the major version number.

It therefore came as a bit of a shock when I viewed this blog using 3.6.12 on my Mac - just about all the text was showing in an italic (or possibly oblique) typeface! My initial panic subsided when I confirmed that everything still looked as expected in every other browser, but this didn't get any closer to resolving the issue. Using Firefox's "Inspect Element" functionality gave no further clues, insisting that the text was in a regular font, despite the evidence in front of my eyes.

A quick hack-up of an HTML test file proved that I wasn't going insane, and that there is in fact a bug in Firefox 3.6:

Screen grab from Firefox 3.6 on Mac OS X, showing Helvetica text rendered at different font-weights.  The text at lower weights is italicized

Some cursory Googling didn't find any reports of exactly the same issue, but this thread (started by no less than Jeffrey Zeldman!) covers similar ground.

I did try explicitly setting the font to be Helvetica Neue Light, but it transpires that Firefox ignores this, and requires you to use font-weight, which as we've just seen is broken - thanks a bundle...

As the bug seems to have been around for a while, and is fixed in the 4.0 betas, I don't hold out much hope of it being rectified in the 3.6.x releases. As a workaround, I've fallen back to using Arial for the headings, as does work correctly with the lower font-weight values.

About this blog

This blog (mostly) covers technology and software development.

Note: I've recently ported the content from my old blog hosted on Google App Engine using some custom code I wrote, to a static site built using Pelican. I've put in place various URL manipulation rules in the webserver config to try to support the old URLs, but it's likely that I've missed some (probably meta ones related to pagination or tagging), so apologies for any 404 errors that you get served.

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About the author

I'm a software developer who's worked with a variety of platforms and technologies over the past couple of decades, but for the past 7 or so years I've focussed on web development. Whilst I've always nominally been a "full-stack" developer, I feel more attachment to the back-end side of things.

I'm a web developer for a London-based equities exchange. I've worked at organizations such as News Corporation and Google and BATS Global Markets. Projects I've been involved in have been covered in outlets such as The Guardian, The Telegraph, the Financial Times, The Register and TechCrunch.

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