Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, Russell Shaw <rjshaw@...> wrote:

> You could measure the intensity spread by using a photodiode behind
> a pinhole in alfoil.

I have a quicker, cheaper (maybe better?) idea: just put a sheet of
bright white paper in place of the PCB. They get paper white by
putting "brighteners" in it, which is just fluorescent colorants that
glow in visible under UV.

I have found it easier to see differences if the paper is not white,
though. I have a pack of that green fluorescent paper stock I use to
make my business cards, you can see the pattern fairly clearly.

Steve Greenfield