Re: [APD] Luxed out

["S. Hieber" <shieber at yahoo_com>]

Lux is a metric measurement (it's a European thing) of
light intensity that a lamp yields on square meter of
planar surface.  Footcandles is a measure of light hitting
a spherical area at 1 foot from the light source (asuming a
point source of light).  You can convert Lux to footcandles
and vice versa.  Since fluorescents shed light in all
directions, even the end of the bulb sheds light on a
square of area that's mostly under the other end of the
lamp.  A longer lamp is likely to have a higher lux rating,
other things being equal.

Lumens, otoh, are a measure of light intensity at the bulb
itself.

Scott H.
--- "Beek, Graham" <Graham_Beek at ds-s.com> wrote:
> Hi group,
> 
> I've become a little confused over lux and it's meaning.
> 
> Looking for a new T8 tube, I was reading the blurb on
> Hagens range which
> include LifeGlo, Sunglo, Powerglo, Floraglo etc and found
> that with
> increasing tube length the lux increased. I thought lux
> was a measurement of
> light (lumens) per metre, so surely the length of the
> tube would be
> irrelevant? Am I missing something?
> 
> Also, Hagen describe their PowerGlo tubes as 'High
> Intensity' and Sunglo as
> a 'standard tube that replicates natural sunlight',
> however the Sunglo tube
> has a higher lux measurement than the PowerGlo (150 or so
> compared with
> 110). This confused me even more.....
> 
> In case it matters the PowerGlo is 18000K, the Sunglo is
> 5000ish (can't
> remember the exact number).
> 
> Any clarification would be greatly appreciated!
> 
> Graham
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