Hi, I'm a bit late on the posting, but this takes me back to my days working in r&d with a small burglar alarm company, where we made all our own boards until the design was proven out. We used u/v sensitive photo resist, had a photo shop make a positive from our printout, sprayed the etch resist on the board blanks, and put the blanks in a box with a glass face, with the photo positive, done on clear film, over the board e.g. photo between the sun and the resist, and left it in the sun for a minute of two. In california, that was enough u.v. exposure to get a full and clear board, and washed the exposed resist off with just water, if I remember correctly. We usually had four circuits per board, and cut them separate with an old school paper cutter, the big cast iron based ones that give a dead straight line. We drilled out two of the locating holes, put four or five boards in a stack, with steel wire in the holes to keep the boards all lined up, and gang drilled the boards. Once the design was working with the rest of the system, we contracted the boards from a comercial board manufacturer by the many hundreds. The issue to me, is the simplicity of spraying etch resist on the blank pc board, laying a clear sheet with the circuit black on it on the surface of the resist, and clamping it all in a picture frame with a piece of say half inch foam on a board with hinges and a latch, to hold the positive print against the glass, the board against the print, and only about a minute of exposure to the sun, to be through with "setting" the etch resist. I'd have traded a horse for the tinning solution mentioned, we had nothing like that there, thirty years ago. We also didn't have laser printers either.