"Derek Geldard" wrote in message
...
On Thu, 26 Nov 2009 15:58:22 +0000, Derek Geldard
wrote:


On Thu, 26 Nov 2009 15:55:10 +0000, Derek Geldard
wrote:

On Thu, 26 Nov 2009 15:23:34 +0000, Frank Erskine
wrote:

On Thu, 26 Nov 2009 14:58:02 -0000, "John"
wrote:

It is a pity we are 'stuck' with relating brightness to wattage. If we
used
a proper definitive measure of brightness then manufacturers would have
to
be more honest.
Brightness is something that can be properly measured with a calibrated
instrument. Relating everything to a poor performing incandescent is
not
good science.

(Lux - Candela - Lumens - whatever)

Foot candles.

Foot Lamberts

Apostilbs


Millinits

magnitude and absolute magnitude.