Homebrew PCBs

Did you peel the protective film off after exposing?  (yes, I still make 
this mistake occasionally myself)

Note: most negative films want a 15 minute "rest" period (in the dark) 
before peeling and developing; the reaction creates some gasses that 
help with the hardening and they need to remain trapped by the film for 
that time.  Check with your board's instructions to see if your film 
needs it.