From: Judy Seigel (jseigel@panix.com)
Date: 03/28/02-11:40:37 PM Z
On Thu, 28 Mar 2002, Sandy King wrote:
> Judy,
>
> As I understand from what you have written about your light source it
> has a mix of different tubes, is wired in part parallel, in part
> series, and the spacing of the tubes is not uniform? Such a unit may
> give inconsistent results depending on where the testing is done.
>
Really Sandy, I've said to the point of tedium all week (almost as bad as
S&G) that the extra spacing of the tubes was only for a test that was done
& gone months ago.... Normally all bulbs are on and as close as they can
be.
As for part parallel, part series -- I don't know where that's from, but
you force me to reveal that I don't know what it means. As I said several
times, showed in photographs & described ad nauseam, my bulbs are on
fixtures, readymade from .... well, some from my son's homegrown, um,
condiments, 25 years ago, and some from Garber & Sons, the local hardware
store. The only IRREGULARITY is that one of the fixtures, the last one in
the row (& not for that matter anywhere near the area lighting the corrent
tests) is broader than the others -- And, as I also said, this caused
absolutely no un-evenness in the print. Nor is this surprising, given that
a much GREATER gap (alternate bulbs covered) caused no irregularity
either.
True, there HAD BEEN an irregularity, but it was corrected by switching
the bulbs... as I showed with the scan in P-F #7, p. 40. If you care to
explain why that worked, be my guest... But, explanation or no, the light
is even.
True, the setup is very low tech... (Shown page 21, P-F #6.) As is the
proof cited. I trust that doesn't rule it out. The light is in fact more
even than the light from the metal halide bulb in my late plate burner,
and needless to say than from single bulbs of any sort.
Meanwhile, my observation is that Alberto's observation that at least half
of any unevenness is from the coating sounds about right. And I also
suppose that double coating would go a long way toward overcoming that...
I DIDN'T double coat because the point was to SHOW whatever unevenness
could possibly be shown.
And for those listening in who don't feel like wiring & ballasting &
grounding, my experience here, with normal supply sources (I do NOT have a
Home Depot within reach & I count my travel time as an expense), it's more
expensive to buy ballasts & other parts & wire your own -- parallel or
serious, than to buy ready to use. Or I should say ALMOST ready to use,
lest someone think I put on the plugs... Electricity is not one of my
talents. But vision is. Tone was as even as possible with single coat by
hand.
Judy
This archive was generated by hypermail 2b30 : 04/10/02-09:28:55 AM Z CST