> An alloy of berrylium and aluminium is used to coat telescope mirrors, but
> when they want the best possible coating, silver is used since it has the
> largest albido of any known substance (i.e. ratio of reflected light to
> incident light). The mirrors are then quartz overcoated to prevent oxidation.
Hi Bob & all,
After everyone's been giving Peter M. such a hard time about
do-it-yourself, I hope they're going to give it to you about "albido",
which maybe I'm not the only one keeps reading "libido". You will
probably claim that definition lets you off the hook, but really,
do-it-yourself is easier.
Meanwhile, such English-speaking people as don't know do-it-yourself
either grew up in the castle, where hard facts of life never penetrated,
or gained consciousness post-WWII. That was when all handy-man types were
suddenly in the army and those accustomed to hiring paper hangers,
painters, & general repair-persons had to learn to do it themselves. In
the immediate postwar period potential handymen all went to law or medical
school on the GI Bill and the phrase "do-it-yourself" was on every lip and
magazine cover....
Anyway, my crinkly aluminum foil was very shiny -- like a mirror. It made
prints hazy, tho I don't think "multiple imaging," unless that's figure of
speech.
So *if* one needed more light & for some reason couldn't or wouldn't bring
paper stage closer to bulbs or move the bulbs closer together, would
painting base reflector white (as mentioned yesterday) or smooth aluminum
"reflector" make much difference?
My *guess* is not, tho I shouldn't, because I know questions like that
are better answered test-wise than theory-wise....
> I think the crinkled aluminum foil generated lots of little hot spots which
> acted like a bank of point sources which resulted in multiple imaging on
> the print.
Cheers,
Judy