Here is a snippet from an article I'm reading: it displays perfectly on screen:
However, when printed some lines appear to be bold (line 5 and 11 in the picture):
Another strange behavior; this is how it looks if I select text on the pdf:
And this is the result when print to xps:
What exactly is causing this? It seems that everything is all right in viewing mode, but goes wrong during the print.
The document is produced with pdfTeX-1.40.3, it's a pdf v1.4 (Acrobat 5.x) and I'm opening it on Adobe Reader 10.1.9, running on Windows 7 x64.