In the article HSL and HSV <https://en.wikipedia.org/wiki/HSL_and_HSV> all the colors at the section 'swatches' <https://en.wikipedia.org/wiki/HSL_and_HSV#Swatches> are not rendered at all. Note that this also happens when printing the page with a pdf printer such as PDFCreator.
Topic on Talk:Reading/Web/PDF Functionality/Flow
This is because browsers don't print background colors and images. This is expected browser print behaviour.
1) When I use PDFCreator, in all my browsers, I have the option 'print background color and images' ticked on and it does not work anyway. Is there a way to have this work? I have the same options enabled and I get the same output when I use the Wikipedia button 'downlad as PDF'.
2) Of course, if I use PDFCreator (or any other similar pieces of software), I expect the output being browser dependent (and browser options dependent). On the other hand, when I push on the button 'download as PDF', I expect the process not being dependent on any browser options or print behavior: this is a feature kindly provided by Wikipedia and it should have nothing to do with a browser printing behavior.
The Wikipedia option is just a browser creating a print using PDFCreator on the serverside :)
The problem here is that it is hard to distinguish backgrounds that you want to include from backgrounds that you don't want to include. There is no method to make that distinction. This will be an unsolvable problem for some years to come still.
Thank you very much for your explanations.