Homebrew PCBs

Hi I've been doing some test on PCB etching and I've been getting nice 
results. But, I realized something, my boards look very different from 
profesional made boards. What I mean is that mine don't have that green 
protective film that professinally made boards have.
Is there a way to apply some kind of protective coat after the board 
has been etched? if so what is its name, manufacturer etc?
Thanks.
Gabriel O lorenzo