I am having trouble with tikz's way of handling colors in patterns. It seems that the problem is linked to the pdf code written by pgf at system level. Following @DavidCarlisle advice, I read some parts of the pdf specification book. But I still have some basic questions about it (googling for questions on the pdf format is not that easy...). So,
- can I ask on tex.se some questions about the pdf format (and if it's ok, should I edit my original question or create a new one)?
- if not, where should I ask?