Re: CP

Barry Meyers-Rice (barry@as.arizona.edu)
Sat, 23 Jan 93 13:01:41 MST

A final photography word or 70

>Could it be that Michael's strobe was unfiltered, but Barry's had a
>plastic diffuser/filter built-in. A powerful strobe puts out about
>50-100 watt-seconds of energy which is roughly comparable to my 10 watt
>UV bulb for 10 seconds.

Hah! Rick, I am an infrared astronomer---I hadn't thought about wavelengths
*shorter* than visible! Interesting suggestion. I don't have the original
specs or owners manual for my ring-light. I know that it is intended
for, among other things, macro work of living subjects. I truly doubt that
a ring light would be produced if it simultaneously illuminated and
sterilized photographic subjects. Anyway, my oft photographed plants are
still alive.

Earl, I still vote for the use of a (non-lethal brand of!) ring-light.
I like the very effects you are arguing against---I find that just one
conventional flash produces shadows that are too dark. A few flashes from
different angles are better, but I like the ring-light illumination. And
it is just the thing you need if the object distance is just a few cm.
But I certainly agree it is not the only way to go...I took some photos of
U. juncea flowers using only backlighting---the flowers are glowing as if
from an internal luminance. Very nice.

I was thinking about Michael's strobe this morning. Michael, your ring-light
*was* a strobe, wasn't it? I mean, it wasn't continually blasting your
plants with a bright light?

Right now in my greenhouse I have about 50 pots of seed for different types of
Sarracenia seed---either crosses I made last season or interesting pure
strains other growers have sent. Last I looked (sunday) I'm starting to
get loads of germination! Spring is on its way.

For those concerned about hibernating your Sarracenia, my new high-low
thermometer says the temperature swings around from 45F at night to 80F
in the day in my greenhouse (perils of Arizona). Even with those high values
my plants stay nicely dormant. The only bad side effects is that some of
my plants, especially S. flava, get confused in the fall by the warm
temperatures. They occasionally produce abnormal fall flowers instead of
waiting for the spring to flower like they should. I know other Arizona
growers that have experienced this problem.

B