Homebrew PCBs

At 7:52 am ((PST)) Fri Feb 2, 2007, Lez wrote:

>On 02/02/07, Len Warner <novost@...> wrote:
> >  The exposure steps should be in a geometric progression
> >  [snip] When making the exposure steps, the times
> >  should be in the ratio: 1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32
>
>Now I should have thought of that, insyead of 1m , 2m etcm as I used
>to take photo's for a hoby many years ago, thanks for remonding me.

Also, it's probably less stressful on the experimenter
to _cover_ the board in steps, rather than uncover it.

This is because it gets the 'fine detail' of the short
exposures out of the way first and the longer ones
do not require such precise timing. Otherwise, your
stress builds up as you proceed ;-)


Regards, LenW