Bit OT. CFLs revisited.

Do you suppose that joint went out and bought Top Dollar CFLs, or the very cheapest -- like their toilet paper? :-)

One thing I noticed is that, since they last so much longer than an incandescent, they get dusty/dirty! I had ocassion to clean the decorative glass shields on the light fixture above the bathroom mirror.

It was a 'rack assembly' with 4 lights. I had to unscrew the CFLs to get the glass shields out. So, as long as I had to handle them anyway, I used a damp, soapy rag to wipe down the tubes of each CFL. The dust and grime being removed was quite apparent as I did it. And, upon reassembly, the light in the room _was_ noticably brighter.

Incandescents just don't often last that long to get that grimy.

Jonesy

--
  Marvin L Jones    | jonz          | W3DHJ  | linux
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That will just make things worse. Compact fluorescent lamps all use trichromatic phosphors, they emit in fairly narrow peaks in blue, green, and reddish orange, you can't create wavelengths that aren't there with filters.

Highest CRI I've seen from a compact lamp is 82, though you can get linear lamps with 90+ CRI but they're slightly less efficient.

I have a nice spectrometer-grade grating, but you CAN just use one of the transparent (unsilvered) blank CDs that you often get at the top of a stack of recordable CD blanks, and just look through it.

The red response from CFLs is interesting. The red is quite narrowband from what I've seen. It also is in CRT TVs. The latter use a yttrium compound to produce red, I believe.

For good colour rendition, you need a nice broad, continuous spectrum, from far-red to far-blue.

You COULD produce "white" using just a red laser, a green one, and a blue one (i.e. all VERY narrowband) so you've effectively got just 3 wavelengths present! BUT the colour rendition would be AWFUL if you used it as room illumination, AND you could come up with coloured cards, or filters, that looked (say) green in sunlight, and looked TOTALLY BLACK under this laser "white" light - for obvious reasons.

Martin

--
M.A.Poyser                                                  Tel.: 07967 110890
Manchester, U.K.          http://www.livejournal.com/userinfo.bml?user=fleetie

It won't look totally black, colored cards or filters are not nearly narrow enough for that, but the color rendering will not be perfect if the emission bands don't exactly match the sensors in the eye. You can in fact have very good color rendition with three fairly narrow emitters, but the problem is finding a good red phosphor. The modern Yttrium based phosphor used in color CRTs and trichromatic fluoescent lamps is orange-red, rather than a pure deep red. It's much more efficient and longer lasting than the old true red phosphor but the CRI will not exceed the mid 80s using it.

Generally speaking, a light source that does a good job rendering reds will have good all around color rendition, red is the hard part.

"James Sweet" wrote >

enough for that, but the color rendering will not be

I disagree a bit, but this is indeed a very complex field. As you say, there are also the response curves of the eye's sensors to consider, but in this case, IF you could find a narrowband-ISH (say) green filter that looked green in sunlight, but whose green peak didn't match the (e.g. 532nm) wavelength of the green laser, it'd look damn near black.

Actually I first thought about this a long time ago, and it's something I'd love to try!

Mostly unrelated, but I believe that the eye's "red" sensor doesn't actually peak in what we call "red". It's more orange, IIRC. It's just that the other

2 sensors drop off so much "earlier" (as lambda increases), that at the red end of visible, that's the only one with ANY response, so we do get a different unique overall perceived colour (i.e. what we think of as "deep red").

Also, there's the thing about the eye's "red" sensor also having response in far-blue/violet, which leads to the confusing things that happen when we look at sources in that part of the spectum, as well as the confusion that arises between violet/purple.

It's interesting stuff!

Martin

--
M.A.Poyser                                                  Tel.: 07967 110890
Manchester, U.K.          http://www.livejournal.com/userinfo.bml?user=fleetie

There's no such thing as a 'white' LED. And even the closest is far far worse than a decent fluorescent.

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    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

Gromit? I just picked up a DVD of "Wallace & Gromit", "The Curse of the Were-Rabbit" :)

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Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Just so ! In Wallace and Gromit - A Fine Day Out, Gromit makes toast for Wallace, and Wallace declares "Cracking toast Gromit !", meaning really good. The phrase has now become firmly lodged in the language over here, and is often used to say that anything is good, or a good idea. The words 'cracking' and 'Gromit' are also used on their own, like I did, for much the same purpose. For what it's worth, although I enjoyed "Curse", for me, the best ones are still the original TV 'shorts' that were turned out by Nick Parks each Christmas. Have you seen them all ? I think that "The Wrong Trousers" is my favourite. All of the story twists and turns are so well observed.

Arfa

Some, but I don't know how many were made. I saw them when I had Direct TV, but with this 20 channel basic Cable service there is very little, other than local channels.

That was a good one. :)

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Energy Saving Bulbs 'Can Cause Migranes' Warn Experts.

.......Larry

snipped-for-privacy@webtv.net wrote in news:23303-477D5872-1992@storefull-

3258.bay.webtv.net:

Slightly different CFL 'headache'.

Wife bought a couple of 4 packs of '40 watt equivalent' CFL bulbs [mfgr unknown].

I put 3 of them in a fixture in the kitchen. Even with the kitchen dimmer at minimum, and the other kitchen lights very dim, the CFLs are almost full brightness.

Shows that they are rather efficient but dimming them may be a bit of a headache.

Also, I note that the package warns about possible radio frequency interference and advises not to use near vital communications equipment.

Argh!

I am going to look for some LED lights.

--
bz    	73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an 
infinite set.

bz+ser@ch100-5.chem.lsu.edu   remove ch100-5 to avoid spam trap

Of course. Their inbuilt power supply tries to overcome any waveform modification a dimmer produces. And you're lucky the dimmer survived.

Which will produce even more nasty light than CFLs. There are more productive ways of saving energy at home without having to pay the price of inferior results.

--
*I don't work here. I'm a consultant

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

The dimmable CFL's typicall cost $15 to $20 ea. Most packages clearly indicate what type they are.

greg

I have one CFL light bulb in my kitchen and one in my bathroom, I never turn those two lights off.I use them only because they last for years.The other light bulbs in my house are General Electric Reveal incandescent light bulbs.In my opinion, CFL light bulbs should be outlawed in America. cuhulin

In my opinion, they should be outlawed world-wide. Period. Suddenly, just as the government here in the UK looks set to ban sales of incandescents, a movement is rearing up to bring to the attention of the great unwashed ( and the dumb politicians ) the potential hazards of using, accidentally breaking, and safely disposing of CFLs. I sincerely hope that it gains sufficient momentum to cast enough doubt over this dreadful knee-jerk technology, to knock its viability as a direct replacement for incandescents, firmly on the head ...

Arfa

I don't want to see either one banned. Most any ban is a knee-jerk reaction from politicians who know little or nothing about the subject at hand. There's ways to encourage use of more energy efficient technology where possible, but there are some applications where incandescent is still the most suitable, and some climates where the waste heat they produce is not really waste. Likewise, I feel that much of the hysteria over lead and mercury in CFLs is unfounded, fluorescent lamps are not the only source of mercury in the environment, and they are not impossible to recycle or dispose of properly. I do feel that any store that sells them should accept dead ones for recycling though, just as is the case with rechargable batteries.

replacement

The amount of mercury in any single bulb is small. And it's elemental mercury, not an organic mercury compound, which is not as toxic as the latter.

We've been using fluroescent lamps for almost 70 years. Their presence didn't seem to cause much in the way of environmental problems. Or scratched hands.

I've replaced several incandescents with CFLs, and I'm very, very pleased. Part of it is that they're in glass fixtures that have a slightly warm cast. You'd never know they're CFLs.

Why do you suppose elemental mercury has been so demonized in the U.S., such that glass thermometers, manometers, barometers, mercury switches, classroom stores and much more are deemed hazards of the highest order and subject to various recalls, seizures and hazmat raids? I had always suspected that vastly more mercury is introduced into the environment from burning coal than could ever reach the food chain from elemental mercury containing devices.

Any idea on the amount of accumulated environmental contamination from lamp tube disposal over the past 70 years? It was never uncommon to observe commercial tubes being smashed into dumpsters for decades...

Regards,

Michael

Gives people something to be hysterical about I suppose. I feel the same way about asbestos and PCBs, I wouldn't spread them on toast or dump them on the ground outside, but I feel they're unfairly demonized and made out to be far more dangerous than they are while other toxic substances are practically ignored.

I can't vouch for this, but a friend commented recently that the asbestos removal guys are running out of work and the latest hysteria is formaldahyde in fiberglass insulation.