I was never very successful at making my own PC boards. I tried the etch-resist pens but the etchant would eat right through them. I tried painting the lines with a very thin brush, and although it worked, I could not make narrow lines. After etching, I soaked and scrubbed to get all the etchant out of the corners where the coper traces met the board, but still got corrosion sometimes after a few months because apparently I didn't get it all out. Where I worked in the mid-1980's and we did wide stripline transmission lines on PC boards for RF power amplifiers, we would cut rubiliths, put a solution on the board and spin it off in the darkroom, then put the rubilith over it and expose it to UV light, then develop it and etch it, and that worked pretty well, but I don't know where to get whatever it was we used, and I know I still couldn't get very narrow lines. A good PC board house can make traces basically no wider than the thickness of the copper, and if you look at them under a microscope, they truly look square. It's amazing. I'm not saying we go that narrow at our company now, but I regularly do .007" traces and they've proven to be 100% reliable. We go down to .008" vias on the smaller .031"-thick boards, and the thru-plating on them has also proven to be 100% reliable. In the 80's, before we had CAD, we use Bishop Graphics patterns and crepe tape we stuck down on dimensionally stable film, usually 2X or 4X actual size, then take them to a graphic arts shop to have them reduced for the PC board house. At that time however, we didn't have any lead spacing closer than .100".