I have recently upgraded from 10.04 LTS to 12.04 LTS (fully up-to-date). Complete fresh format and install of the Linux partition.
I noticed that PDF files printed from Firefox 14.0.1 and Chromium 18.0.1025.168 (Developer Build 134367 Linux) sometimes do not contain selectable text. However, initially, I didn't realize it was in some way dependent upon the web page being printed.
After some time, I discovered that printing only some web pages result in un-selectable text [text is image only], in both Firefox and Chromium. For example. However, printing some pages result in selectable text, for example.
So far as I can tell, the problem seems to affect both Firefox and Chromium equally, although I have only tested on several web pages, including the BBC. So far, I have not found a page which affected one browser and not the other.
Initially I thought it might be a damaged CUPS-PDF (because this had always worked before in previous Ubuntu versions), but I removed and reinstalled that. I also removed and reinstalled Firefox. I believe it doesn't appear to be postscript, although I don't really understand the details of how pages are constructed for printing – (I removed and reinstalled GV). Restarts made no difference. I found that printing to PDF from LibreOffice isn't apparently affected.
So, I'm beginning to suspect that it's most probably in Linux, or in both browsers – but that seems rather less likely, but it could be something else that affects both browsers.
I have to say that I'm stumped. Please help!