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Re: Lumens per liter
George Booth <booth at frii_com> wrote:
> >Date: Wed, 6 Dec 2000 08:53:49 -0700 (MST)
> >From: "Roger S. Miller" <rgrmill at rt66_com>
>
> >Well, all those details are far too involved to constitue a "rule of
> >thumb". I suspect that the 30-50 lumen per liter rule is based on nominal
> >lumens -- i.e. on the lumen rating of the light source. If you need to
> >base something on actual lumens then probably you're better off getting a
> >meter, measuring lux and converting to lumens.
>
> Gosh, once you have a lux meter, why go back to goofy lumens? That's sort
> of like figuring out how many gallons of gas you put in your fuel tank by
> dividing miles traveled by what your car thought it did in miles per
> gallon. Why not just read the gas pump meter? Lux is what you really want -
> the actual intensity as produced by the lumens coming form the bulb and
> bouncing off the reflector. Hey you can even tell how bright it is at the
> bottom after all the shading and light piping takes place. Cool!
OK, but I guess the idea here is to have an estimate of the illuminance level
*before* you buy/build/design the lighting system. The light meter will
only work with an existing, operational system, not with one still in the
design phase.
- Ivo Busko
Baltimore, MD