This topic came up recently...look for a thread started by DocToxyn here. Gokul and I both recommended "kits" readily available from art stores (not sure about what would be available in Holland though), and DocToxyn might have found something else as an alternative (not what he originally suggested in the thread, which involved some pretty nasty chemicals not readily available to the public). I can't quite remember now.
Ferric chloride is used to remove copper plating from PC board material. The copper you want to keep is masked. I don't know how deep you can remove with it. Sometimes there are problems where the acid 'undercuts' and goes underneath the mask.
Find someone who does laser engraving. Spray paint your copper and have them burn off the paint with the laser where you want to remove copper. I've had excellent results with this. Once etched, use laquer thinner to remove the paint.