Date: Wed, 19 Mar 1997 14:57:02 -0500 (EST) From: Perry Malouf <pmalouf@access.digex.net> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg990$foo@default> Subject: Re: Lights
Chris Teichreb wrote:
> ...The light itself is about 25inches long
> ...It puts out 33 watts. Pretty good for a little light.
It's more probable that the light _consumes_ 33 Watts.
The luminous output is a different matter.
The field of photometrics is somewhat complicated and
uses obscure terminology, but it is precisely this field
which accurately describes light intensity, luminous
flux, and other concepts that are important.
Since the various terms are pain to deal with for most
people, lamps are rated according to the power they
consume.
Let's say you're comparing fluorescent lights: a 25 Watt
tube and a 50 Watt tube. Let's also say that you have a
visual impression of what the 25 Watt tube puts out. You
can then gauge (roughly) what the 50 Watt tube puts out.
But don't compare the 25 Watt fluorescent with a 25
Watt incandescent source. The two technologies have
different power-to-light conversion efficiencies (and
different effective temperature)and so the visual
impressions won't be the same. This is so, despite
the fact that they both consume 25 Watts of power.
Want to vastly simplify things for yourself? Purchase
a good light meter. With very little trouble you
can gauge the light output of any source you intend
to buy. You may also be surprised at how
your visual perception differs from an objective
measurement of light.
Regards,
Perry Malouf
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