One of the first things I noticed after booting into Ubuntu 9.04, Jaunty Jackalope, is that Google Reader and Gmail looked a bit off. I quickly realized they were both using different sans-serif fonts than they had previously (Nimbus Sans), despite Firefox’s preferences having Nimbus set as the default sans.
I knew that Google isn’t so great with their stylesheets, in some cases declaring a font-family of just “Arial,” with no “sans-serif” backup in the font-stack (which would, of course, let Firefox substitute in whichever default sans the user had set – in my case, Nimbus).
I also knew through playing around with ~/fonts.conf that Linux allows you to define substitutions for different font names. It was my hunch that there was something new about Jaunty (which has been praised for its better presentation of text) that defined Liberation Sans – the font I determined I was looking at – as the preferable substitute for Arial.
After looking around a bit I found the culprit in /etc/fonts/conf.avail/30-metric-aliases.conf. Around line 182 you should see the beginning of a section devoted to the Microsoft typefaces, and shortly under that (around line 186), the line:
Just above that, insert the following line:
<family>Nimbus Sans L</family>
Reboot your system, and when you’re back up, Ubuntu should now replace any calls for Arial with Nimbus Sans.
Of course, this should only be done if you prefer Nimbus Sans. It’s been claimed that Liberation Sans is better hinted than either Nimbus or FreeSans, and from the looks of things, it is. Still, I just prefer Nimbus. That serif on the upper-case ‘J’ in Libertine especially bothers me.
I still love Linux Libertine as a Times substitute, however.