What's the brightest LED ? what's the chance they will replace Flourescent lights in

[NewBie]

Reference?

These lamps maintain 95% output after 10,000 hours.

Actually, I'm seeing a 10% drop in lumen output at 10,000 hours from multiple references, for the T8, others state an early 8% drop to 92% output from the get go, then it stays there for awhile. Example:

http://www.alliantenergy.com/docs/groups/public/documents/pub/p012398.hcsp


Rapid starting fluorescents sacrifices life:
High-performance T8 systems:
A dedicated program-start electronic ballast provides longer lamp life than standard systems. The average rated life is 30,000 hours, compared with 20,000 hours for rapid-start systems and 15,000 hours for instant-start systems.

There are some other quirks...
You can get 37,000 hours of life if you operate them 24 hours a day.

But, if the bulb spends half its time off, and half it's time on, only being turned on once a day, the life drops to 28,900 hours.


However, not all T8 bulbs are rated the same for life specs.
3 years* (7,500 hours rated life)
http://www.gelighting.com/na/home_lighting/products/fluorescent/36_inch.htm


However, there are fancier high end commercial bulbs (instead of consumer bulbs), which have higher life ratings, and better lumen maintenancee, with things like the fancy starcoat and such:
T8 Ecolux - TCLP Compliant 4' w/ Starcoat F32T8/SP30/ECO
http://genet.geappliances.com/Light...rescent&subcat=L2-49&viewcode=IDS&chkView=IDS


When looking at life on fluorescents, you have to acertain how the test was actually done. Some companies use the 3 hour on, and 3 hour off. Others use a continous 24 hours per day burn. This is very important for comparing life and lumen depreciation...

As usual, the devil is in the details.

100lm/W for T8 is for the ultra premium high end T8.
There are plenty of 74lm/W consumer grade T8 bulbs, and even more 83lm/W consumer grade bulbs.

Then you have to buy more expensive high end electronic ballast (and those also have a wide range of efficiencies). Some folks like to claim the ballasts are 100% efficient, but they aren't. LRI did some testing, and on the last report I saw, they actually ranged from 83 to 92% efficient. This lowers the lumens per watt...

Forget the low cost magnetic ballasts, especially those sold with many T8 fixtures, you loose alot of efficiency there...


Oh, and before I forget, long life bulbs often get dust, dirt, oil films, and such on them and in the non-sealed fixtures. This also causes a drop in lumen output, as well as many of the white reflector paints dim or yellow with age add in an additional lumen loss. Some companies offer high end fixtures, with very special paints, and even silicone gasketed fixtures, to seal them from dust and such. It is easy to get a 10% drop in lumens for typical fixtures in typical areas over just a 36 month period. Here are some numbers for extra clean filtered areas:
"The Figure above contrasts the new LDD function with lensed and louvered fixtures in clean conditions. It assumes better-than-average air filtration and some generated or ambient dirt. At 18 months, the LDD factor is 0.92 versus 0.84-0.85 using the traditional IESNA procedure. And at 36 months, the LDD factor is 0.89 versus 0.75-0.80."
http://www.ecmweb.com/mag/electric_designing_lighting_systems/index.html

One more thing...
Since fluorescents radiate all around them, it is usually necessary to have reflectors in most applications. It is not uncommon to see an additional 15 to 40 percent loss in lumen output due to the reflector in the fixture. Yes, you can get high efficiency fixtures, which have uber expensive coatings, but these will cost you a pretty penny. It is also not uncommon to have a diffusion grating/plastic patterned diffuser in front of the T8 fluorescent bulbs, which results in further lumen loss, which will range an additional 8 to 15% loss in lumens.

In reality, one must look at the entire picture, taking in account all the factors...

 

[jtr1962]

You can reach a CRI of ~95 or ~100 lumens/watt, but not at the sametime.
A 32W 4' lamp can make 3,100 lumens with the CRI of 86, but if you get a 92 CRI lamp, you will only get around 2,000 lumens.

You can do better than that with pentaphosphor lamps. Look at these, for example. CRI 91, 3300 lumens, 32 watts, and a rated life of 34,000 hours. Besides that, at only $5 each in 100s these don't have ultra-premium pricing. At this point these are the only T8 lamps I buy.

 

[NewBie]

You can do better than that with pentaphosphor lamps. Look at these, for example. CRI 91, 3300 lumens, 32 watts, and a rated life of 34,000 hours. Besides that, at only $5 each in 100s these don't have ultra-premium pricing. At this point these are the only T8 lamps I buy.

Looks like nothing is free...are those bulbs really depreciating like that?

http://www.fullspectrumsolutions.com/full-spectrum-light-bulb-comparison.htm

Looks like more than one company has these.
http://www.paralite.com/3.14.0.0.1.0.shtml
http://www.bluemaxlighting.com/full_spectrum_fluorescent_bulbs_33_ctg.htm
http://www.ultra-lux.net/fluorescent_bulbs.shtml

Can you find a real datasheet anywhere for your bulbs?

Some folks don't like the extra blue in these bulbs:
http://www.irritatedvowel.com/Railroad/Layout/Lighting/Lighting.aspx


Apparently the Paralite bulbs (fullspectrumsolutions) fiddles a bit with the spectrum and converts the tri-phosphor spectrum into something called a relative spectrum, from their actual spikey spectrum, and a few other stretches.
http://www.bluemaxlighting.com/full_spectrum_fluorescent_bulbs_33_ctg.htm

From Paralite's own page, see down at the bottom for the actual spikey spectrum:
http://www.paralite.com/fluorescent_bulb_compare_lights.shtml


There is a problem with these blue enhanced bulbs, that some say is a health danger, references stated include:
"The photoreceptors in the retina . . . are susceptible to damage by light, particularly blue light. The damage can lead to cell death and diseases." Shaban H, Richter C. A2E and blue light in the retina: the paradigm of age-related macular degeneration. Biol Chem 2002 Mar-Apr;383(3-4):537-45.

"The effectiveness of light in inducing photodamage to the retina increases with decreasing wavelength from 500 to 400 nm." Andley UP,? L.T. Chylack Jr LT. Recent Studies on Photod amage to the Eye with Special Reference to Clinical and Therapeutic Procedures. Photodermatology Photoimmunology and Photomedicine 1990; 7:98-105.

See above here:
http://72.14.203.104/search?q=cache...Lite+fluorescent+T8&hl=en&gl=us&ct=clnk&cd=26

From a macular degeneration website, information on the dangers of the blue spectrum and harm caused by excessive blue of the bulbs like the Paralight brand:
http://www.mdsupport.org/library/hazard.html


One of the little tricks of these high output blue Paralite, Bluemax, etc. is to blast a huge amount of blue at your eyes, which causes the pupil to decrease in size, which has the effect of making things look sharper. (But, one really should read about the dangers of excess blue that I listed right above) Anyhow, a little discussion on the Paralite, and the "blue-storm" output of the Paralite Bluemax:
http://www.bluemaxlighting.com/choose_bluemax.htm

They like to spin things alot saying their spectrum is identical to the sun. It isn't. It's full of empty space and spikes. The color temp is the same though, but you could do the same exact thing with two narrow band lasers...or two colored LEDs. Color temp and spectrum are quite different.

Their claims in action:
http://www.bluemaxlighting.com/natural-lighting.htm


Their actual spectrum, notice the very excessive and extremely high amplitude, very narrow, huge blue spikes, near UV, and UV spikes- all of which are damaging to the human eye over time, and dangerous to folks with the propensity for macular degeneration:

 

[jtr1962]

Can you find a real datasheet anywhere for your bulbs?

Not really, but I can tell you they look as bright or brighter than any of the normal triphospher tubes with a similar claimed lumen output,and the colors are much better.

From Paralite's own page, see down at the bottom for the actual spikey spectrum:
http://www.paralite.com/fluorescent_bulb_compare_lights.shtml

All fluoro lights have some spikes. The spikes in the UV region in particular are from the primary mercury arc and those are present in every tube.

There is a problem with these blue enhanced bulbs, that some say is a health danger, references stated include:
"The photoreceptors in the retina . . . are susceptible to damage by light, particularly blue light. The damage can lead to cell death and diseases." Shaban H, Richter C. A2E and blue light in the retina: the paradigm of age-related macular degeneration. Biol Chem 2002 Mar-Apr;383(3-4):537-45.

I remember this being discussed a few times here. The general consensus is you'll be exposed to far more blue light by going out in sunlight than you would even in a brightly lit room. Also, UV exposure from sunlight will be orders of magnitude higher. Unless you're prone to macular degeneration, which most people aren't, using these fluorescents isn't an issue. The author's suggestions for alternative light are less than desireable both from a visual standpoint and an aesthetic one. The yellowish incandescent lighting he recommends both distorts colors and induces horrible headaches in quite a few people (myself included). Maybe the best recommendation if you're prone to macular degeneration is to avoid as much light as possible, period.

That spectrum is for the 5900K version of the tubes. The 5000K that I use has somewhat less blue. Also, many full spectrum light manufacturers are getting away from putting UV in their spectrums since the claimed benefits of UV are bogus, and there are definitely problems associated with it. If nothing else, it will fade paint and fabric over time. Don't forget, the diffusers present is most fluorescent fixtures will absorb a good portion of the UV coming out the tubes anyway.

 

[jtr1962]

Re: What's the brightest LED ? what's the chance they will replace Flourescent lights in

I also meant to add that the study of 6 different lights is fundamentally flawed because the intensities aren't the same (fluorescent can't be focused as sharply as incandescent). Therefore, the conclusions reached that the three incandescents provide the best seeing is simply because they have the highest intensity. And they purposely chose 3 fluorescents which can at best be described as mediocre even if two of them were labeled as "full-spectrum" (a catch-all label often given to any lamp with a CCT from 5000K to 6500K regardless of light quality). Another line makes the whole study suspect:

Contrast diminishes with increasing CCT. Because of their "blueness," lamps 5-6 provide noticeably less contrast than lamps 1-4. The best contrast is achieved by the opposites of black and white, and that cannot be done with blue light.

Funny because I've always heard that higher CCT gives better contrast, not worse. Long wavelengths tend to make things appear fuzzy. This is an unfortunate byproduct when using red light to preserve night vision, for example.

Another ridiculous assertion from the study:

Lamps 5-6 are not as easy on the eyes as lamps 1-4. Because of its "blueness," a cloudless day at noon (i.e. "daylight" at 5000K) is not as comfortable for our eyes as the warmer colors of late afternoon. Lamps 1-3 emit light closer to the warm yellow and orange end of the visible color spectrum, with lamp 3 being the "whitest," due to its relative evenness across the visible spectrum.

Interesting how the authors feel millions of years of evolution directed our visual systems to feel comfortable in a lighting condition which only exists for a fraction of the day as opposed to one which is usually present for most of the day. And an even, or equal energy, spectrum has a CCT of about 5800K, not the 4100K of the Solux lamp used as lamp 3.

It seems to me the authors set up the study in such as way as to guarantee the outcome they desired. I could just as easily set up a study showing narrowband blue or green or red or any other color is optimal for seeing by using the preferred lighting source in much greater intensities than the others.

BTW, I believe the increase in retinal disease each year is from a combination of better diagnosis and the thinning of the earth's ozone layer, not from the overuse of bluish light as the authors would like to believe. It was probably never a good idea to spend too much time in direct sunlight anyway, even prior to the thinning of the ozone layer. The thing is in the days when people spent more time outdoors most people were killed off by something else before dying from cell damage due to UV exposure.

 

[NewBie]

Re: What's the brightest LED ? what's the chance they will replace Flourescent lights in

It isn't the author's being biased jtr1962. In fact, it looks to be one of the least biased reports I have seen.

If you look at the tremendous list of research by various doctors, and their list of papers at the end, it is hard to say they are biased.

Also, if you have ever used a keyboard with 450-470nm blue, you'll find it is very fuzzy, blue doesn't really help much to sharpen things, in fact, there is a lack of blue receptors (just a small fraction as compared to green and "red") in the central area of the eye...

I count 81 papers listed from various authors/institutions:
- Professor and Vice Chairman/Director of Macula Service, Department of Ophthalmology, University of Kansas Medical Center

-K.A. Rezai, E.M. Gasyna, K.A. Rezaei, W.F. Mieler. AcrySof Natural Filter Decreases the Blue Light Induced Apoptosis in Human Retinal Pigment Epithelium. Ophthalmology & Visual Science, University of Chicago, Chicago, IL.

- M.Hammer, S.Richter, K.Kobuch, D.Schweitzer. Lipofuscin Accumulation in an Organotypic Perfusion Culture of Porcine Fundi Under Oxidative Stress and Blue Light Irradiation. Department of Ophthalmology, Univ. of Jena, Jena, Germany; Department of Ophthalmology, Univ. of Regensburg, Jena, Germany.

- Chair of the American Academy of Ophthalmology Vision Rehabilitation Committee. Medical Director, Henry Ford Health System Visual Rehabilitation and Research Center, Grosse Pointe and Livonia MI

- Professor Emeritus of Optometry and Physiological Optics, University of Houston College of Optometry

- Professor, Department of Ophthalmology, University of Zurich

- Professor, Department of Psychiatry, Columbia University. President, Center for Environmental Therapeutics, New York NY.

- Science 295: 1070-1073

- Ophthalmology 2004;111:297-303

- Sparrow JR, Zhou J, Ben-Shabat S, et al. Involvement of oxidative mechanisms in blue-light-induced damage to A2E-laden RPE. Invest Ophthalmol Vis Sci 2002;43:1222–7.

- Boulton M, Rozanowska M, Rozanowski B. Retinal photodamage. J Photochem Photobiol B 2001;64:144–61.

- Sparrow JR, Zhou J, Cai B. DNA is a target of the photodynamic effects elicited in A2E-laden RPE by blue-light illumination. Invest Ophthalmol Vis Sci 2003;44:2245–51

- Rozanowska M et al. Blue light-induced reactivity of retinal age pigment. In vitro generation of oxygen-reactive species. J Biol Chem. 1995 Aug 11; 270(32): 18825-30.

- International Commission on Non-Ionizing Radiation Protection. Guidelines on limits of exposure to broad-band incoherent optical radiation (0.38 to 3
microM). Health Phys 1997;73:539–54.

- Kremers JJ, van Norren D. Two classes of photochemical damage of the retina. Lasers Light Ophthalmol 1988;2:41–52.

- Rapp LM, Smith SC. Morphologic comparisons between rhodopsinmediated and short-wavelength classes of retinal light damage. Invest Ophthalmol Vis Sci 1992;33:3367–77.

- Feeney L, Berman ER. Oxygen toxicity membrane damage by free radicals. Invest Ophthalmol 1976;15:789–92.

- Director of Vision Program Development, The Jewish Guild for the Blind

- B.Optom., M.Sc. (Petah Tikva, Israel)

- MIESNA, Photometry Specialist SESCO Lighting, Inc., Fort Lauderdale FL

The list goes on an on and on... see more here:
http://www.mdsupport.org/library/hazard.html

I'd really have to arrive at the conclusion that it was the reader that was biased, not the article...

 

[jtr1962]

Re: What's the brightest LED ? what's the chance they will replace Flourescent lights in

It isn't the author's being biased jtr1962. In fact, it looks to be one of the least biased reports I have seen.

The study is what's biased. It was set up in such a way as to arrive at the conclusion the author wanted-namely that light with more blue in it is bad for seeing. The author did this by not using the same intensity for all the lamps, and by purposely choosing fluorescent lamps whose spectrums were far from state of the art (the much hyped Ott Lite has been shown in comparisons to other full spectrum lamps to be lacking). I have no idea as to the author's motives for wanting this conclusion. I'll hazard a guess that since many other studies on the negative effects of blue light were listed, the author wanted to show that light with more blue offered none of the claimed advantages of increased contrast or better seeing. This is counter to my own personal experience, and many other research papers I've read. I even tried it today. I lit up some things with an incandescent flashlight and then an LED one. In all cases the LED was crisper, more natural, more pleasant. I switched all my lighting to fluorescent years ago for similar reasons. Even the crappy cool-white tubes of years ago offered better seeing than incandescents.

If you look at the tremendous list of research by various doctors, and their list of papers at the end, it is hard to say they are biased.

I'm not disputing that an excessive amount of short wavelength light is hazardous. I only question whether you would receive a dangerous amount via artificial lighting. Indoor lighting levels seldom exceed 1000 lux, or 1/50 of what you'll get outside on a bright day. Given that most people who work outdoors exposed to sunlight for 8 hours a day for decades don't develop the things in these studies, I find it almost impossible to believe that any normal level of artificial lighting, regardless of spectrum, could cause them.

Also, if you have ever used a keyboard with 450-470nm blue, you'll find it is very fuzzy, blue doesn't really help much to sharpen things, in fact, there is a lack of blue receptors (just a small fraction as compared to green and "red") in the central area of the eye...

Things look fuzzy under any narrow-band light, whether red, amber, green, blue, etc. The human visual system is best adapted to work with white light.

I'd really have to arrive at the conclusion that it was the reader that was biased, not the article...

Even assuming I didn't find the study fundamentally flawed and accepted the conclusions as valid, what are the practical implications of it? That we should all go back to using incandescent light and energy conservation be damned? Given that the visual system evolved to deal with sunlight, I simply find the conclusions that incandescent light is better for seeing astonishing as they are counter to my lifelong experience. There are also many studies which show blue light to be beneficial, most of them dealing with seasonal affective disorder. I think the only valid conclusion we can draw here is that anything in excess, including blue light, is harmful. In the end studies like this remind of dietary studies. Some study will find a certain thing is harmful in quantities far greater than any person is likely to consume, and then all of a sudden everyone will try to banish the ingredient completely from their diet.

I'm not losing any sleep worrying if my fluorescent tubes are causing me any damage. Maybe they will cumulatively over 5000 years, but I'll certainly be dead long before then of other causes. Given the superior light they offer compared to anything else currently available, plus the energy savings, there is really no alternative anyway for now. Hopefully in a few years we'll all be lighting our houses with LEDs which have no UV emissions at all, and no sharp spikes of blue or any other color. RGB LED lighting would certainly fit that bill.

 

[NewBie]

Re: What's the brightest LED ? what's the chance they will replace Flourescent lights in

Funny because I've always heard that higher CCT gives better contrast, not worse. Long wavelengths tend to make things appear fuzzy. This is an unfortunate byproduct when using red light to preserve night vision, for example.

Things look fuzzy under any narrow-band light, whether red, amber, green, blue, etc. The human visual system is best adapted to work with white light.

Humm, I find things look the most fuzzy under blue. The low count of blue receptors in the central portion of the eye, with the majority of them in the outlying areas, would definitely explain it.

As folks age, their cornea turns more and more brown. Older folks need more blue for things to seem the same color of white. I've known middle aged folks that have had their lenses replaced, and are quite surprised at how blue the sky really is.

As far as the harm to the eye, I'll have to defer to all the papers published by the doctors and researchers that he referenced. I'm not a doctor.

http://www.mdsupport.org/library/hazard.html

I do wonder, with a broad band- low amplitude blue in daylight, the somewhat broad blue of blue LEDs, as compared to the super high narrow spike amplitude of these Paralite and especially BlueMax Paralite bulbs vs. the amount of harm to the eye. At least in one of those papers the author was worried about the wide band output of a blue LED, vs. the broad band output blue of the sun. A blue LED is nothing compared to the super narrow high amplitude spike of the Paralite brand bulbs...

 

[NewBie]

Re: What's the brightest LED ? what's the chance they will replace Flourescent lights in

Has anyone ever checked out the Phillips TL-D 90 DE LUXE PRO 36W/950 SLV/10 Commercial Code: TLD36W950

With a 98% CRI?

http://www.lighting.philips.com.au/...ontent_id=163910&tab=details&subtab=technical


It is interesting to note how fluorescents hate to be turned off and on. Just turning them off and on every three hours results in a 20% loss of life, a 30k hour bulb becomes a 24k hour bulb.
http://www.nam.lighting.philips.com/us/ecatalog/fluor/pdf/p-5369.pdf

It is interesting to note the spectum on the new Phillips TL950 bulbs, which don't have the skyscraper tall blue spike of the Paralite bulbs...

But do have a 98% CRI

More info here:
http://www.nam.lighting.philips.com/us/ecatalog/fluor/pdf/P-5037-D.pdf

 

[jtr1962]

Re: What's the brightest LED ? what's the chance they will replace Flourescent lights in

Humm, I find things look the most fuzzy under blue. The low count of blue receptors in the central portion of the eye, with the majority of them in the outlying areas, would definitely explain it.

I never really compared fuzziness under different colors of narrow-band light although seeing isn't that great under any color. Might be an interesting experiment although the results aren't really that relevant here since we're really talking about shades of white light. Basically, my own personal experience plus a number of papers I've read show better contrast under white light with more blue as opposed to with more red. It's still basically white light in either case, with a far wider spectral distribution than a colored LED.

As folks age, their cornea turns more and more brown. Older folks need more blue for things to seem the same color of white. I've known middle aged folks that have had their lenses replaced, and are quite surprised at how blue the sky really is.

Well, the sky still seems very blue to me, and for what it's worth I found incandescent light horribly yellow compared to daylight as soon as I noticed things like that (probably by about age 5).

I do wonder, with a broad band- low amplitude blue in daylight, the somewhat broad blue of blue LEDs, as compared to the super high narrow spike amplitude of these Paralite and especially BlueMax Paralite bulbs vs. the amount of harm to the eye. At least in one of those papers the author was worried about the wide band output of a blue LED, vs. the broad band output blue of the sun. A blue LED is nothing compared to the super narrow high amplitude spike of the Paralite brand bulbs...

I never really trust graphs like that compared to a plot of the SPD using proper equipment. The spikes could be exaggerated for marketing purposes. Don't forget as I mentioned earlier the diffusers on most fluorescent fixtures will filter out almost all the UV and some of the blue. Besides that, the inverse square law is your friend here. It's not like most people sit 1 foot under a fluorescent tube.

Another thing I'm thinking about right now is the relative energy in that spike compared to the same wavelength band in sunlight. Sure, the wavelength band in question is inarguably a greater percentage of the total light output from the fluorescent tube as compared to sunlight, but sunlight is at least 100 times as intense, so it probably contains more total energy in the same wavelength band than the fluorescent tube (and lots more blue light outside that band which the fluoro tube only has in much smaller amounts). The real question is at what threshold is harm done? It seems we can all conclude that at least some people who are in the sun all day will suffer problems but do we exceed some threshold with our artificial lighting? I really can't answer that, although intuitively I doubt it unless you're regularly exposed to artificial light levels in excess of 10,000 lux. Far too many of those studies had results based on using narrow-band blue light. You really can't draw too many conclusions based on that. For one thing, if you're exposed to blue light only, your pupil will be open wider than the same intensity of green light, for example, and let proportionately more of it in. Since the shorter wavelength blue is more harmful than green per photon, it will of course do lots more damage. Now put the same intensity of blue but mix it with the proper proportions of other colors to produce white light. The pupil will open much less, and you will get far less, if any, damage. Yes, the studies show us that intense narrow-band blue light is something to be avoided, but that's not something you would use for general lighting anyway.

For what it's worth, LED lighting will address these concerns. Whether we use RGB or blue + phosphor, the resulting SPD won't possess the obnoxiously large spikes present in many fluorescent tube spectra.

It is interesting to note the spectum on the new Phillips TL950 bulbs, which don't have the skyscraper tall blue spike of the Paralite bulbs...

But do have a 98% CRI

Yep, the spikes will be smaller precisely because the spectrum is more balanced. That's also what gives us the CRI of 98. The obvious downside is reduced efficiency relative to the Paralite (64 lm/W versus 103 lm/W for new tubes).

 

[Handlobraesing]

I never really compared fuzziness under different colors of narrow-band light although seeing isn't that great under any color. Might be an interesting experiment although the results aren't really that relevant here since we're really talking about shades of white light. Basically, my own personal experience plus a number of papers I've read show better contrast under white light with more blue as opposed to with more red. It's still basically white light in either case, with a far wider spectral distribution than a colored LED.


Well, the sky still seems very blue to me, and for what it's worth I found incandescent light horribly yellow compared to daylight as soon as I noticed things like that (probably by about age 5).


I never really trust graphs like that compared to a plot of the SPD using proper equipment. The spikes could be exaggerated for marketing purposes. Don't forget as I mentioned earlier the diffusers on most fluorescent fixtures will filter out almost all the UV and some of the blue. Besides that, the inverse square law is your friend here. It's not like most people sit 1 foot under a fluorescent tube.

Another thing I'm thinking about right now is the relative energy in that spike compared to the same wavelength band in sunlight. Sure, the wavelength band in question is inarguably a greater percentage of the total light output from the fluorescent tube as compared to sunlight, but sunlight is at least 100 times as intense, so it probably contains more total energy in the same wavelength band than the fluorescent tube (and lots more blue light outside that band which the fluoro tube only has in much smaller amounts). The real question is at what threshold is harm done? It seems we can all conclude that at least some people who are in the sun all day will suffer problems but do we exceed some threshold with our artificial lighting? I really can't answer that, although intuitively I doubt it unless you're regularly exposed to artificial light levels in excess of 10,000 lux. Far too many of those studies had results based on using narrow-band blue light. You really can't draw too many conclusions based on that. For one thing, if you're exposed to blue light only, your pupil will be open wider than the same intensity of green light, for example, and let proportionately more of it in. Since the shorter wavelength blue is more harmful than green per photon, it will of course do lots more damage. Now put the same intensity of blue but mix it with the proper proportions of other colors to produce white light. The pupil will open much less, and you will get far less, if any, damage. Yes, the studies show us that intense narrow-band blue light is something to be avoided, but that's not something you would use for general lighting anyway.

For what it's worth, LED lighting will address these concerns. Whether we use RGB or blue + phosphor, the resulting SPD won't possess the obnoxiously large spikes present in many fluorescent tube spectra.


Yep, the spikes will be smaller precisely because the spectrum is more balanced. That's also what gives us the CRI of 98. The obvious downside is reduced efficiency relative to the Paralite (64 lm/W versus 103 lm/W for new tubes).

Smoothness and spikes isn't what determines the CRI.

That's an SPD of a ~CRI 63 Cool white, yet it is much smoother in spectrum than the CRI 80+ tri-phosphor variant available today.

 

[Handlobraesing]

Actually, I'm seeing a 10% drop in lumen output at 10,000 hours from multiple references, for the T8, others state an early 8% drop to 92% output from the get go, then it stays there for awhile. Example:

http://www.alliantenergy.com/docs/groups/public/documents/pub/p012398.hcsp


Rapid starting fluorescents sacrifices life:
High-performance T8 systems:
A dedicated program-start electronic ballast provides longer lamp life than standard systems. The average rated life is 30,000 hours, compared with 20,000 hours for rapid-start systems and 15,000 hours for instant-start systems.

There are some other quirks...
You can get 37,000 hours of life if you operate them 24 hours a day.

But, if the bulb spends half its time off, and half it's time on, only being turned on once a day, the life drops to 28,900 hours.

Because we're talking about the best LEDs, it's only fair to compare them against the best flurosecent. The information you cite speaks rather generally and not specific to any products.

Saying T8s are.... is just like saying LEDs are... without considering the merits of specific products.

http://www.nam.lighting.philips.com/us/ecatalog/fluor/pdf/p-5369.pdf

You will see that "mean" lumen is the maintained lumen after 40% of lamp life have elapsed and these lamps are rated 24 to 30K hours, which means 95% is maintained after 9.6 to 12K hours. Note that your information comes from some dealer while what I just said comes from a reputable international lamp manufacture.

However, not all T8 bulbs are rated the same for life specs.
3 years* (7,500 hours rated life)
http://www.gelighting.com/na/home_lighting/products/fluorescent/36_inch.htm

That's an older switch start type that's been around for decades rated based on switch-start application.

However, there are fancier high end commercial bulbs (instead of consumer bulbs), which have higher life ratings, and better lumen maintenancee, with things like the fancy starcoat and such:
T8 Ecolux - TCLP Compliant 4' w/ Starcoat F32T8/SP30/ECO
http://genet.geappliances.com/LightingeCatalog/Dispatcher?REQUEST=GETPRODUCTDETAILS&pcode=26666&category=FLU&text=Fluorescent&subcat=L2-49&viewcode=IDS&chkView=IDS

These are the newer, modern design, the 265mA T8 series.

When looking at life on fluorescents, you have to acertain how the test was actually done. Some companies use the 3 hour on, and 3 hour off. Others use a continous 24 hours per day burn. This is very important for comparing life and lumen depreciation...

Look in the Philips Catalog. I believe they use 3 hours.

As usual, the devil is in the details.

100lm/W for T8 is for the ultra premium high end T8.
There are plenty of 74lm/W consumer grade T8 bulbs, and even more 83lm/W consumer grade bulbs.

Please cite a source that differentiates T8 lamps between commerical and consumer grades.

Then you have to buy more expensive high end electronic ballast (and those also have a wide range of efficiencies). Some folks like to claim the ballasts are 100% efficient, but they aren't. LRI did some testing, and on the last report I saw, they actually ranged from 83 to 92% efficient. This lowers the lumens per watt...

However, the published lamp specs are under 60Hz operation. The efficacy of the lamps themselves improves when operating at higher frequency, which offsets the ballast loss you've discussed above.

Refer to IESNA Lighting Handbook.

Forget the low cost magnetic ballasts, especially those sold with many T8 fixtures, you loose alot of efficiency there...

Oh, and before I forget, long life bulbs often get dust, dirt, oil films, and such on them and in the non-sealed fixtures. This also causes a drop in lumen output, as well as many of the white reflector paints dim or yellow with age add in an additional lumen loss. Some companies offer high end fixtures, with very special paints, and even silicone gasketed fixtures, to seal them from dust and such. It is easy to get a 10% drop in lumens for typical fixtures in typical areas over just a 36 month period. Here are some numbers for extra clean filtered areas:

This is not a problem unique to fluorescent.

"The Figure above contrasts the new LDD function with lensed and louvered fixtures in clean conditions. It assumes better-than-average air filtration and some generated or ambient dirt. At 18 months, the LDD factor is 0.92 versus 0.84-0.85 using the traditional IESNA procedure. And at 36 months, the LDD factor is 0.89 versus 0.75-0.80."
http://www.ecmweb.com/mag/electric_designing_lighting_systems/index.html

One more thing...
Since fluorescents radiate all around them, it is usually necessary to have reflectors in most applications. It is not uncommon to see an additional 15 to 40 percent loss in lumen output due to the reflector in the fixture. Yes, you can get high efficiency fixtures, which have uber expensive coatings, but these will cost you a pretty penny. It is also not uncommon to have a diffusion grating/plastic patterned diffuser in front of the T8 fluorescent bulbs, which results in further lumen loss, which will range an additional 8 to 15% loss in lumens.

In reality, one must look at the entire picture, taking in account all the factors...

 

[Handlobraesing]

You can do better than that with pentaphosphor lamps. Look at these, for example. CRI 91, 3300 lumens, 32 watts, and a rated life of 34,000 hours. Besides that, at only $5 each in 100s these don't have ultra-premium pricing. At this point these are the only T8 lamps I buy.

Spec wise, they look better, but measuring the CRI is even more complicated than the actual output itself and there's a complicated calculations involved in objectively rating the CRI and they could easily get away with BS'ing, because realistically, nobody will pay thousands to get their products tested.

Same with cheap flashlights that claims outrageous lumens. Who's going to put them to test with an integrating sphere?

When I looked at the name, I thought.. "who the hell is this company?". Do they have the R&D and track record to substantiate their claims? No. I think not. Do they have their own testing facilities? Unlikely, if so, did they provide the name of the accredited lab who have conducted? No.

BlueMax lighting, what the heck?
They've filed the name with the trademarks office in Jan 2005. Been in use since April 28th 2005, per Patents & Trademarks office records. Haven't even been on the market for a year and they're already claiming the bulbs have a life of 34,000 hours?

 

[NewBie]

Re: What's the brightest LED ? what's the chance they will replace Flourescent lights in

One of the things people miss is the SPD, which they will re-rate and diddle on the chart and fill in the spectrum like on the example that Handlobraesing showed on his cool white example. The spectral power plot of a Cool White doesn't look like that. When I see the filled in areas of a fluorescent bulb, I know folks are pulling the wool over my eyes. A simple 10 dollar spectrometer can show you this.

Here is something from a long time ago, using a spectrometer:

The same fluorescent bulb, but using my Minolta CS-1000 Spectoradiometer:

You can see down at the bottom of the page, where even Paralight takes their own spectrum, and twiddles it, like the folks did in Handlobraesing's example of Cool White, to obtain an interesting conversion which makes the bulb look extra smooth. One of those marketing ploys, imho:
http://www.paralite.com/fluorescent_bulb_compare_lights.shtml

 

[Wim Hertog]

The same fluorescent bulb, but using my Minolta CS-1000 Spectoradiometer:

This is clearly a triphosphor lamp, unlike the cheapo cool white fluorescents which use halophosphate phosphors.

 

[Handlobraesing]

One of the things people miss is the SPD, which they will re-rate and diddle on the chart and fill in the spectrum like on the example that Handlobraesing showed on his cool white example. The spectral power plot of a Cool White doesn't look like that. When I see the filled in areas of a fluorescent bulb, I know folks are pulling the wool over my eyes. A simple 10 dollar spectrometer can show you this.

Here is something from a long time ago, using a spectrometer:

The same fluorescent bulb, but using my Minolta CS-1000 Spectoradiometer:

You can see down at the bottom of the page, where even Paralight takes their own spectrum, and twiddles it, like the folks did in Handlobraesing's example of Cool White, to obtain an interesting conversion which makes the bulb look extra smooth. One of those marketing ploys, imho:
http://www.paralite.com/fluorescent_bulb_compare_lights.shtml

The height of the spike also depends on the minimum resolution of the spectrometer setting.






These are from Osram-Sylvania reference. Former is "cool white", latter is tri-phosphor type of same color temp. Note that its more spiky, yet offers superior CRI.

 

[jtr1962]

Re: What's the brightest LED ? what's the chance they will replace Flourescent lights in

What's interesting here is that triphosphor tubes have large peaks and valleys in their spectrum yet offer CRIs as high as 86 while the spectral plot of an white LED is much smoother yet the CRI is typically in the high 70s. Another thing which came up in another thread during a discussion about using RGB LEDs for general lighting was a study NewBie linked to that showed CRI wasn't terrible important. People actually largely preferred several combinations of RGB LEDs with CRI far lower than the other light sources used for comparison. Maybe we need a new metric here.

 

[Handlobraesing]

What's interesting here is that triphosphor tubes have large peaks and valleys in their spectrum yet offer CRIs as high as 86 while the spectral plot of an white LED is much smoother yet the CRI is typically in the high 70s. Another thing which came up in another thread during a discussion about using RGB LEDs for general lighting was a study NewBie linked to that showed CRI wasn't terrible important. People actually largely preferred several combinations of RGB LEDs with CRI far lower than the other light sources used for comparison. Maybe we need a new metric here.

The CRI function weighs the response curve of our eyes, so when it comes to photography, human-eye response weighed CRI becomes irrelevant. Films tend to prefer continuous spectrum as mercury lines cause high exposure of some layers and giving a green cast.

For film photography , I think Tailored Lighting's SoLux 4700K would work great.

 

[tron3]

Re: What's the brightest LED ? what's the chance they will replace Flourescent lights in

LED house lights are still a few years away for low end usage.

The article said the Osram LED bulb was 120 Lumens. Heck, any of my 5w LED's can generate that. 120 lumens is great for a flashlight, but pretty weak compared to a "weak" 40w bulb of 360 to 400+ Lumens.

Saw a 120 Lumen spot light bulb which is good for outside nightlights near the garage and such.

 

[Handlobraesing]

LED house lights are still a few years away for low end usage.

The article said the Osram LED bulb was 120 Lumens. Heck, any of my 5w LED's can generate that. 120 lumens is great for a flashlight, but pretty weak compared to a "weak" 40w bulb of 360 to 400+ Lumens.

Saw a 120 Lumen spot light bulb which is good for outside nightlights near the garage and such.

I just don't see the economical benefit in LED general lighting UNLESS, they significantly exceed the efficacy of the currently available fluorescent system with a price tag low enough to have a cost advantage and not just the stated 100,000 hour life, but actually backed by warranty.

Certain ballast/lamp combination for fluorescent systems are already available with 3 year warranty which covers lamp replacement cost labor as well.