Homebrew PCBs

The first exposure is long enough that the areas you want to stay on are 
somewhat hard, take it out, remove the artwork, wash off the uncured 
pads, then re-expose (without artwork since you have cleaned off the 
areas you were masking anyway) to fully cure.

Paul Alciatore wrote:
>  
>
> I have not heard of this soldermask and am puzzled. You expose it the
> first time with the artwork and then expose it again for a lot longer
> time without the artwork. I am curious as to how this works. It seems
> like it would all just harden. Can you post some links to this that
> may explain it better?
>
>