Homebrew PCBs

Adam Seychell <a_seychell@...> writes:
> So the photoresist professionals say you must expose the resist such
> that when you put a 21 step gauge, the resist under step 8 should be
> about "%50" cured. I assume "%50" cured means its gets heavily
> eroded by the developer but not quite enough to be completely
> removed.

More like some parts come completely off, and other parts remain
intact.  I guess the parts that remain could be thinner, but I didn't
check.

> In this situation, the actual energy during PCB exposure will then
> be 11.3137 times the amount of energy needed for "%50" cure. I think
> this is what your saying above.

Yes.