Homebrew PCBs

Quoth Andrew at 2008-06-06 08:46...

> Matthew - it is kinsten stuff I had that I
> found to have lost a lot of sensitivity and
> a little bit of contrast when many year out
> of date.
> 
> However sometimes when I order the Kinsten
> boards from Perth they come in different
> shades depending on batch.  They range from
> drab green to bright green.  So there may
> even be marked difference in the "past used
> by" performance in the one brand.

Thanks Andrew.  The moral of this story is, therefore, to run a test 
strip on every batch of stock.  Have a small strip of board and a film 
of parallel lines.  Partially cover the strip, expose for a minimum 
length of time.  Uncover a bit more strip, expose for a little longer. 
Rinse, then repeat.  Develop - and possibly even etch - the strip and 
see which exposure time worked best.  I think that the term is 'bracketing'.

Cheers

M


-- 
Matthew Smith
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