I try to save a page as a PDF file but it loses the background colors. I figure this is a standard setting for a printer, but when I save as a PDF I prefer the background colors to stay. How can this be done?
Firstly, I'm not sure it has any relation to Ubuntu... :)
Secondly, there may not be a good generic way to save a website page to PDF while keeping the background - think of pagination, page numbering, titles etc. Think of white text on dark background. In many cases the results won't look good - that's why browsers fall back to white background. Also, many sites use separate stylesheets for printing, which additionally remove elements which are not needed on paper - navigation, menus etc.
What you need is a way to make a screenshot of the whole page - this will preserve all detais of the page how you see it. There are plugins for Firefox to do this - I suppose there may be something for Chrome too.
The Firefox plugin I used is called Screengrab