In alt.engineering.electrical Paul M. Eldridge wrote:

| As with the halogens I identified above, incandescent lamp life is
| based on the same 50 per cent rule -- that is an industry-wide
| standard. For a graphical representation of this, see page 2 of:
|
| http://www.sylvania.com/content/disp...x?id=003694068

Then something's out of whack somewhere. I see far more than 50% of bulbs
last beyond 750 hours of usage. That didn't catch my attention before as I
did not assume something like the 50% basis.


|| If long life is important, some of the new Philips T8s fluorescents
|| have a rated service life of up to 46,000 hours but, then, as you
|| indicated in another thread you refuse to use linear fluorescents in
|| your home due to potential concerns related to Hg. On that basis, I
|| presume we can rule out metal halide as well.
|
|That's not my primary concern. It is a concern, and one that _may_ limit
|my use of them. My primary concern is the poor spectrum (not the color) of
|every fluorescent light I have ever seen. What I am referring to is that
|the spectrum is not as uniformly continuous as incandescent. These are
|therefore ruled out for critical task lighting areas (especially kitchen
|and shop).
|
|
| Sorry for my confusion. When you said "What about long tube
| fluorescent lights that I also refuse to put in my home for the same
| reason?" in relation to our other discussion pertaining to Hg, I
| understood the word "refuse" to be an absolute.

It might be absolute. I'm actually undecided at the moment. This applies
to the design of my new home, which I have not timeline, yet, for building.
I'm refusing to put fluorescent fixtures into that design unless and until
I see some solid proof I should not be concerned with it.


| If your primary concern is good light quality, there are fluorescent
| lamps with a very high CRI such as the Philips TL930 (95 CRI) and
| TL950 (98 CRI), but if you require something better than that, it's
| probably best to stick with an incandescent or halogen source. And if
| you're concerned your access to these lamps may be restricted at some
| future date, you can always stock up on whatever you use now as a
| precaution.

My primary concern is an aspect of light quality that has nothing to do with
the CRI rating. As I understand it, CRI refers to the balancing of color in
the spectrum within the confines of how human eyes perceive it so the color
of illuminated objects looks correct or natural. My concern is more with the
way the spectrum affects contrast edges given that human eyes, and worse when
corrective or magnifying lenses are involved, do not focus the light spectrum
at a single point. Under a single visible wavelength, contrast edges always
look as sharp as the viewer can see them. Under a broad continuous spectrum
of white light, the edges will be slightly blurred, but will be uniform. But,
under a the harsh light of 3 distinct single wavelengths, that edge will look
like 3 distinct colored edges. That's the worse situation. Fluorescent light
corrects this poorly because its spectrum has "hills and valleys" despite the
color balance being a reasonable white. LED has the same issue but I think
there may be more hope to correct this for LED than for FL (since FL has been
around for so long and this hasn't been fixed). Some HID has less of an issue
with it. MV and MH are bad, but HPS seems to be OK (though it has very poor
color in the eye of many).

As for stocking up, I'm not worried. There will be a black market. There
always is. It's not like they are going to put that much effort into this.
It's not like pirating software/music/movies.

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