From: John Campbell (tojohn@texas.net)
Date: 12/11/01-10:47:04 PM Z
Sandy,
It's John, not Jeff-and I'm with both you and Judy (if I read you rightly).
I'm betting against banding from UV tubes at any distance from the glass on
out.
A Million Monopoly Bucks.
And there's more where that came from.
I will take issue with the claim made by someone (you, as I recall) that the
inverse square property applies to point-source light, but not to diffused
light. How can this be? Granted, the filtering agent limits certain
wavelengths-but the rule still applies to the escaping waves, right? (or
particles, depending on your persuasion)
Are there no physicists or astronomers at Clemson who could clarify these
matters? Gosh. I had always heard it was a good school.
Regards,
John
www.photogecko.com
-----Original Message-----
From: Sandy King [mailto:sanking@clemson.edu]
Sent: Tuesday, December 11, 2001 12:35 PM
To: alt-photo-process-l@skyway.usask.ca
Subject: Re: I'll see that bet, and raise you (Was: UV Article)
Jeff,
I missed something in your message. Are you betting for or against
Judy? Please clarify. Inquiring minds want to know.
Sandy King
>Okay-deal me in: Given (1) the relationship of brightness to distance; and
>given (2) the diameter of fluorescent tubes (other than the late "thin"
>varieties, fashionable for kitchen cabinet applications, but not widely
>respected for UV radiation); it would seem to reason that a print in direct
>contact with the glass of a given set of tubes on 1/4" or greater centers
>would experience (not consciously, of course) as equal a distribution of
>light as one at 3" distance-or one at 30", for that matter; or 30
yards-from
>the light source. The difference would be in intensity, not in
distribution
>of radiance. (Note, also, that the hypothetical 1/4" centers are less than
>possible under the conditions of (2) above, confirming the premise.)
>
>Hence, no banding1
>
>N'est pas?
>
><<John dramatically throws down a cool million Monopoly Dollars>>
>
>Has anyone out there actually experienced banding or stripping from UV
>tubes?
>
>If so, Judy will gladly cover my bet-while l am looking for a new tanning
>salon.
>
>(Personal aside to Sandy: please give my regards to Beth Daniels in the
>English Dept. at Clemson, a fine Rhetorictician, and Very Clear Thinker.
>She knows much about light and is a de-light-full human being.)
>
>Regards to all,
>John
>
>www.photogecko.com
>
>1- a term better suited to my Epson 3000 printer, but I won't quibble.
>
>
>
>
>-----Original Message-----
>From: Sandy King [mailto:sanking@clemson.edu]
>Sent: Monday, December 10, 2001 10:56 PM
>To: alt-photo-process-l@skyway.usask.ca
>Subject: Re: UV Article
>
>Judy Seigel wrote:
>
>>
>> > I think this is a legitimate concern. If you are using the two-tube
>>> holders with 3/4" spacing between the tubes there is some point in
>>> bringing the tubes closer to the contact frame where you are going to
>>> get so close that banding (or stripping) will take place. I will bet,
>>> for example, that if you place the contact frame at 1-2" from the
>>> tubes there would be some banding on the print.
>>
>>
>>How much is that bet? I'm finishing some tests that I will show in
>>upcoming P-F, and though, as noted, I rarely bet less than a million
>>dollars, I'm very soft-hearted.
>>
>>J.
>
>
>
>I won't take your bet on this because I actually hope you are right.
>I recently replaced my bank of 24" tubes with very close spacing
>(about 1/4") with a larger bank of 48" tubes with 3/4" spacing and
>have assumed up to now that it would be necessary to use the new bank
>farther from the exposing plane than the old bank, which I was using
>at about 2". If I can actually use the new bank at the same distance
>as the old one, without banding, so much the better.
>
>
>
>Sandy King
>
>
>
>
>
>
>--
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