From: William Laven (wmlaven@platinotype.com)
Date: 02/12/00-03:40:36 PM Z
>On Fri, 11 Feb 2000, William Laven wrote:
>>
>> ... while the Philips graph indicates such a precipitous drop, I've not
>> seen that with my printers (several of my own and several which I use in
>> workshops). That is, my exposure times didn't have dramatic increases in
>> response to the suggested decrease in lamp output.
>
>It occurs to me to wonder if the UV drops at the same rate as the visible
>light... that is, do we know that Philips was measuring the same thing
>that the Metrolux -- or your emulsion -- measure?
>
>Judy
I've wondered the same. The Metrolux is outfitted with a cell which reads a
fairly broad band of light. After using it for a couple of years I thought
about getting a cell which measured a narow band of UV only, but my
exposures were working fine so it was sort of a "If it ain't broke, don't
fix it" situtation. One could argue, theoretically, that the Metrolux,
outfitted with a narrow band UV cell would work more precisely -- basically
the light integrators everyone talks about are just that: a closed loop
system measuring light output.
BUt, you know, there are so many other variables at play and so many things
I've done to "control" them that at one point I figure, hey, this sytem is
working for me and I'm not going to spend my dying days trying to eek out a
few percentage points of "more accurate" exposures. And, anyway, sometimes
those prints which come out a little flatter or more contrasty or lighter
or darker help me imagine the imaginbe the image in different ways anyway
so they're not such a terrible thing.
I'd much prefer a system which makes politicians accountable, predictable
and consistent than I would one for my prints!
********************************************************************
WILLIAM LAVEN PHOTOGRAPHY
Tutorials in Platinum/Palladium printing and Zone System.
1931 23rd Street, San Francisco, CA, 94107
415-647-9432 (voice) 415-647-9438 (fax)
wmlaven@platinotype.com
http://www.platinotype.com
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