My father made a simple PCB himself a few years ago. He designed the PCB with http://www.geda-project.org/ http://www.geda-project.org/ (I think?), printed out

My father made a simple PCB himself a few years ago. He designed the PCB with http://www.geda-project.org/ http://www.geda-project.org/ (I think?), printed out a negative of the PCB on a (printer-safe!) transparent page, and used an old overhead projector as the light source for the etching. That being said, I suspect that methodology doesn't scale down to such small features, multiple layers etc. that you see in the link you posted, so at some point you have to give up on DIY etching.