From: Judy Seigel (jseigel@panix.com)
Date: 04/01/03-02:20:00 PM Z
On Mon, 31 Mar 2003, Christina Z. Anderson wrote:
> I'm not surprised Shelley's exposure was almost 2 hr in rainy weather.
> Another one of these tidbits I've picked up from research--from Ware's
> book--is that the sun is about several times faster than artificial sources,
> and the north sky is 1/10 the speed of direct sun. North sky would even be
> more sunlight, I would think, than cloudy/rainy. So a 20 minute exposure
> under UV would equate to 7 minutes in the sun and 70 minutes under north sky
> (and who knows what under rain). Does anyone's research agree with Ware's?>
Chris, trust me, there are more variables in heaven and earth than even
Mike Ware has dreamed of .. you CAN'T make a formula of ratio of sun to
"artificial sources" unless at the VERY LEAST you quantify those sources
-- what light at what distance and what paper. Also what season, what
climate, and what time of day -- since low sun is filtered through
whatever is reigning at the moment, and that's the least of it.
Again, honest -- this is NOT something you RESEARCH !!!! It's something
you TEST. And I'll add that in october, close to mid day, my students
found that 5 minutes outdoors in Brooklyn was about equal to 6 minutes
indoors.
HOWEVER, SHELLEY ! MIX UP YOUR CHEMICALS A DAY IN ADVANCE. NOBODY SEEMS
TO HAVE NOTICED MY ADVISORY THAT VERY FRESH CHEMICALS CAN WASH OFF OR
OTHERWISE BE GOOFY. I doubt you'd get a 2 hour exposure even at the north
pole if everything else is in order.
Are you using GREEN ferric ammonium citrate?
Did you say what paper you're using?
And you're buying chemicals in such small amounts that 2 tests use them
up? From where? That's odd at best.... tho this is a perfect example of
how ordinary "classroom instruction" can make these processes seem
difficult and untrustworthy. So is lighting the stove if you don't know
what those little knobs are for.
Judy
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