Homebrew PCBs

I'm interested in that approach too.
But little extended. The old fashion PCB process have aperture wheel. 
and there was different shapes on it. So instead just thiny dot there 
can be bigger dot's too. And this can speed up process a lot. Now the 
light source. It's need to be UV period. And some laser's can do that 
but there is problem as we can't(easy) build that as is invisible and 
commercial UV laser (0.5 to 1W) isn't cheap. The scrap source is blueRAY 
disc. But managing the optic is near inposible. The other source is UV 
LED. But led light should be collimated too. But least the UV led has 
little visible light so we can manage to focus them. Another UV source 
is mercury light. It's just BIG but can be used.

We just need to know how long the dot must be developed and then we know 
if process is ussable or it's to slow.