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

[Stephen7372]

the near future ?

These articles may be of interest
http://www.physorg.com/news4538.html

However how many lumens of light does a 60 Watt incandescent produce ? (820 lumens ??)

Is this the brightest ?
http://cgi.ebay.co.uk/ws/eBayISAPI.d...tem=8023783990

[ikendu]

I notice that Advance Mart sells these "25 watt" replacement bulbs that only draw 2.5 watts.

http://store.advancedmart.com/11acsc34whle.html

Compact Flourescents use about a 1/4 of the power of an incandescent, apparently LEDs draw about a 1/10th. ...and, LEDs aren't done yet with improvements or innovations.

I do think that in 10 years, maybe most houses will be set up to use LEDs.

If nothing else, the increasing costs for energy will start drawing attention to these technologies.

[Sleestak]

I do think that in 10 years, maybe most houses will be set up to use LEDs.

If nothing else, the increasing costs for energy will start drawing attention to these technologies.

The only way I see LED's making strong inroads into the home lighting market is for their price to come down substantially. Right now, trying to purchase an LED bulb for the house is prohibitive costwise, especially considering the performance.

Also, Flourescent technology is really coming on strong right now. Used to be you could go the the local Home Despot and find a small row or two of flourescent screw in bulbs. Now, you can go and find pallet stacks of them. So, I think that flourescent technology will generally rule for the upcoming future; however, I do think that LED technology will come along strong, and will become the 'new thing' that replaces flourescents at some point in the future. It will also come down to someone coming up with more or less of a 'Mazda bulb' standard so that all LED's perform similarly regarding color hues. Nobody wants to light their house with cold colors. Someone'll have to come up with nice sunlight hues first. That's what's pushing flourescents a little right now, that they can come in warmer colors than once they could.

It's kind of exciting, really. I'll be cuing up for LED fixtures just as soon as they get better pricewise.

[joema]

Even the most efficient white LEDs can't match current fluorescents. The above mentioned Osram Ostar has lots of output, but is apparently not an efficiency leader. Whenever Osram releases a datasheet we'll know for sure, but I've seen one source saying it's 40 lumens per watt.

The most efficient LEDs produce roughly 60 lumens per watt, but that's typically when underdriven so light output may not be useful. When normally driven, efficiency typically drops by about 1/3 to 1/2, or around 30-40 lumens per watt. More details in this thread: http://candlepowerforums.com/vb/show...ghlight=sphere

By contrast compact fluorescents reach about 70 lumens per watt, and T8 fluorescent tubes can reach about 90 lumens per watt, including ballast losses.

There's also a big difference between the efficiency of current shipping residential LED fixtures vs the datasheet efficiency of discrete LEDs. Current shipping fixtures are often around 25 lumens per watt, which may include transformer/rectifier losses.

So in a commercial or residential lighting application, current shipping T8 fluorescent tubes (inc'l ballast losses) have about a 3x efficiency advantage over the best discrete LEDs when normally driven, about a 2x efficiency advantage if the LEDs are under driven, and about a 3.5x efficiency advantage over current shipping residential LED fixtures.

Efficiency of LED residential fixtures will probably further improve, but they have a long way to go before matching the best current fluorescent tubes.

[LEDninja]

Take a look at this thread. Nice pictures by a CPFer who converted his home to LED lighting.
http://candlepowerforums.com/vb/show...household+bulb

My post (#7) has the lumen ratings for compact flouresets and also show the equivalent incandescent bulb.

WARNING
NONE of the LED bulbs I purchased are UL listed nor CSA approved. All 115 volt equipment should be tested for fire and electrical shock safety, and the approval stamp should be on it. Equipment 24 volt and under (that's most flashlights) are not required to be tested.
There was a recall of LED Christmas lights in Novia Scotia due to fire hazard from a faulty component. (And those lights were previously CSA approved)

[Cavannus]

Comparaison between incandescent, fluorescent and led lighting is not so easy...

First, there is a psychological effect, and according to Kruithof's curve, for a same subjective perception of comfort (and a good comfort is often perceived as a good light output... yes!), actually less "warm" light output is needed than "cold" light output.
(http://www.learn.londonmet.ac.uk/packages/clear/visual/people/ambience/colour/)


So, incandescent lamps have a poor efficiency, but as the light seems "warm" (3000 K), this "pleasant" efficiency is not perceived as so bad. On the contrary, a led beam may seem not very bright because its color temparature is "cold" (6000 K).
Subjectively: "not pleasant" is perceived as "not good", and at the end "not good" is perceived as "not bright enough"...


Second, for an identical overall flux, light distribution is not the same for incandescent/led and fluorescent.
Incandescent and led allow to use a reflector, and the narrow beam will give a perception of a bright source.
Fluorescent, despite its very good efficiency, does not allow to use a beam, so :
- for low intensity lamps (flashlights), much light is "lost" so it doesn't seem powerful nor bright at all => led seems more efficient, more brighter (in subjective terms);
- for high intensity lamps (indoor lighting, at home or at the office,...), where general lighting is required, fluorescent lamps give much homogeneous light, so they seem brighter than leds or incandescent.

Third, don't forget life duration... Many lighting system efficiency decrease after a few hours: it is bright in the shop, it is poor at home... Especially when fluo or led lamps are boosted!

I hope this will balance the objective (true) values given above, and help to understand why a fluorescent flashlight seem less bright than a led flashlight, despite lm/w efficiency values.

(And sorry for my English, this is not my mother language)

[jtr1962]

Nobody wants to light their house with cold colors. Someone'll have to come up with nice sunlight hues first. That's what's pushing flourescents a little right now, that they can come in warmer colors than once they could.

Sunlight = ~5000K, incandescent = 2700K to 3000K. I agree that most 5mm LEDs are too cold to light a house with, coming at at 8000K and up. However, I'm starting to notice a surge in popularity of so-called sunlight fluorescents which will hopefully soon carry over to wider availability of CFLs in 5000K instead of the more common 2700K or 3000K. Sure, 5000K is somewhat "colder" than your average incandescent, but don't go on the blanket assumption that "nobody" wants anything but incandescent-like lighting in their homes. I personally can't stand incandescent lighting (and I wouldn't like 8000K LED lighting much either) but I find 5000K very nice.

What's helping fluorescents more right now isn't necessarily that they can come in warmer colors (they did have a so-called incandescent fluorescent years ago but it was even more horrid than the cool whites of the day) but rather that their color rendering has improved greatly over the horrid standard greenish cool whites from years ago, plus electronic ballasts have eliminated flicker. Those were the usual drawbacks most people complained about when asked why they didn't use fluorescents. However, I think the CFL manufacturers misinterpreted people a bit when they may have said "the color is all wrong" or something similar. They thought the people meant that the color was wrong because it wasn't like incandescent instead of meaning the color was wrong because some colors were missing or distorted. As a result, early Energy Star legislation more or less dictated CFLs with color temperature similar to incandescent, supposedly to increase acceptance. IMHO, this is exactly the reason they're still not terribly popular even though they are catching on. Quite a few of the potential early adopters of CFLs didn't want to spend $20 on a bulb which gives light exactly like the incandescent they were replacing. While the energy savings was certainly an attraction, a more immediate benefit would be more natural (i.e. closer to sunlight) lighting. Indeed, even before the first energy crisis got people interested in fluorescents there were a fair number of people who used them in their homes precisely for better lighting. As strange as it may sound, I personally preferred even the old school cool whites on a magnetic ballast to incandescent which I always found horrible, even as a kid. Anyway, yes, most of the CFLs these days are still the horrid warm white but I've noticing a gradual interest in 5000K sunlight. Daylight is also finding a niche, although for many people the jump to 6500K is just too much to tolerate in one shot, which is why it hasn't really taken off.

I'm personally looking forwards to the day, hopefully within 5 years, were reasonably-priced LED incandescent replacements start to make their way to the shelves. More recently Energy Star legislation simply requires that bulbs be labeled with their color temperature and thus has no bias to warm white as the old legislation did. This and gradually changing preferences will hopefully mean LED replacements will be readily available in 2700K, 3000K, 3500K, 4100K, 5000K, and 6500K so the end user can pick whatever suits them. Incidentally, it seems within LED circles that 3500K is becoming a sort of new standard for "warm white", implicately acknowledging the trend I'm seeing towards lighting the home with whiter light. Remember that incandescent never was ideal or even close to it. It was merely all we had for a long time, and people simply got used to it, just as they had been used to candles when they were in use. Another topic entirely there, namely how quickly people can get used to, even prefer, something that isn't necessarily optimal, or even close to it.

[jtr1962]

First, there is a psychological effect, and according to Kruithof's curve, for a same subjective perception of comfort (and a good comfort is often perceived as a good light output... yes!), actually less "warm" light output is needed than "cold" light output.

This isn't what Kruithoff's curve tells us at all. Rather, it tells us that at lower lighting levels what is perceived as pleasant will have a lower color temperature than what is considered pleasant at higher lighting levels. From a practical perspective, this means that higher color temperature lighting needs to have higher intensity to "feel" right. Note that this has nothing to do with the light being good for seeing or considered "good light output". It is merely that psychologically at low light levels high color temperature lighting "feels" wrong even though it is actually better for visual acuity, and you need fewer photopic lumens to perform a given task because of this. Candles or dimmed-down incandescent might be perceived by many people as creating a relaxing atmosphere at low light levels, but the color (and light level) are horrible for actually getting anything productive done.

Subjectively: "not pleasant" is perceived as "not good", and at the end "not good" is perceived as "not bright enough"...

The first part of the sentence is correct, but it's a bit stretch to come to the conclusion that "not good" is perceived as "not bright enough". In general, a person will only complain about light levels if they're not adequate for the task. They may complain the light feels wrong if the color isn't to their liking, of course, but I've yet to hear a person say a room lit with a few LEDs isn't bright enough because the light isn't pleasant to them while one lit with an incandescent night light bulb is bright enough because they like the light. Rather, they will only complain the room is too dim if they can't perform whatever task they're trying to accomplish, which in this case might simply be moving around the room without banging into things. For a given lumen level, the LEDs would actually be superior in that regard owing to their scotopically superior spectrum even if they might not be perceived as pleasant.

One thing I find very suspect about Kruithoff's curve are the findings at very low light levels even if the findings are fairly valid at higher light levels. Supposedly the preference tends towards 1500K (candlelight) at these very low light levels (1 lux and under) but the fact is that at these same low light levels your eyes are incapable of distinguishing color at all, so how can you have any color temperature preference if you're not seeing color? If anything, what is perceived as the best light at these low levels should be whatever type of light best matches our scotopic sensitivity. For those reasons I think with a proper test the color temperature preference would start back up again at a few lux since higher color temperature lighting would be perceived as brighter at low light levels compared to the same intensity of low color temperature lighting. Furthermore, eventually at extremely low light levels there should be a marked preference not for white light, but for monochromatic cyan, since this color is at the peak of scotopic sensitivity. Note that at these low light levels the person wouldn't even be aware that the light is monochromatic since they aren't seeing in color, but merely that it seems brightest. Yes, at very low light levels brightness and pleasantness are indeed interchangeable since there is no other basis for perception due to the fact that color vision is inactive. However, at higher light levels these terms are not interchangeable. A person may indeed say a light which they don't find pleasant still appears brighter than one that they like.

[EricB]

However, I think the CFL manufacturers misinterpreted people a bit when they may have said "the color is all wrong" or something similar. They thought the people meant that the color was wrong because it wasn't like incandescent instead of meaning the color was wrong because some colors were missing or distorted. As a result, early Energy Star legislation more or less dictated CFLs with color temperature similar to incandescent, supposedly to increase acceptance. IMHO, this is exactly the reason they're still not terribly popular even though they are catching on. Quite a few of the potential early adopters of CFLs didn't want to spend $20 on a bulb which gives light exactly like the incandescent they were replacing. While the energy savings was certainly an attraction, a more immediate benefit would be more natural (i.e. closer to sunlight) lighting. Indeed, even before the first energy crisis got people interested in fluorescents there were a fair number of people who used them in their homes precisely for better lighting. As strange as it may sound, I personally preferred even the old school cool whites on a magnetic ballast to incandescent which I always found horrible, even as a kid. Anyway, yes, most of the CFLs these days are still the horrid warm white but I've noticing a gradual interest in 5000K sunlight. Daylight is also finding a niche, although for many people the jump to 6500K is just too much to tolerate in one shot, which is why it hasn't really taken off.

I always hated the brown incandescent light, and wished they would have cool white in a bulb. (I wanted mercury bulbs, until I found that they needed ballasts, even if they weren't large base size). So when CFL's first came out, that seemed the answer, except for the cost. By the time the costs came down, and they were more readily avaiable, almost all now emulated incandescent color. Actually, even though this is now called "warm white, this is really soft white, and "warm white" was the first attempt of CFL's to try to emulate incandescent color, with a sort inbetween hue that was paler than incandescent. I believe this color was in the 3000's K, and was basically close to what is called "lunar white". But then they "perfected" the incandescent color, and "daylight" became hard to find. I always wondered why they had to copy the quaint old incandescent color, and when I heard people say it was easier on the eyes or something like that; I figured that must be why. I didn't know that it was mandated that they be that color. I guess I could see why warm tans would be preferable for reading (I just liked the bluer whites because they were different, and "modern" looking). But as you said, I guess something in between, that more emulates sun color would be best.

I gradually replaced all the lights in my apartment with CFL's, and hunted to find some daylights for the kitchen (because I was used to cool white Circlines in kitchens; soft white doesn't look right), and the bathroom because it has a nice two tone blue tilework which looks better with daylight, and also the bedroom, because I always wanted daylight for the bedroom.

Now, they have LED's that exactly match incandescent color, but they don't seem to be catching on. You would thin they would immediately take over LED flashlights, but all the ones I've seen use the bluish white.

[jtr1962]

I always wondered why they had to copy the quaint old incandescent color, and when I heard people say it was easier on the eyes or something like that; I figured that must be why. I didn't know that it was mandated that they be that color.

It wasn't mandated in so many words that CFLs had to be warm white so much as they had to have a certain CCT range (2600K to 3100K IIRC) to receive the Energy Star label, or if not within this range they had to be labeled "Daylight". That pretty much left the consumer with only two choices-warm white which many felt was too yellow, and daylight which was sort of a catchall for anything which wasn't in the CCT range I mentioned earlier. As a result, since "daylight" fluorescent had traditionally been 6500K this was what most of the daylight CFLs were, but you could also package 4100K, 5000K, or for that matter even 8000K as "daylight". That's another thing which hurt the sales of daylight CFLs-unless the package was labeled with a color temperature, which by law it didn't have to be, it was a guessing game as to what hue you were actually getting. At the $20 a pop early CFLs sold at, nobody wanted to play such a guessing game. Later Energy Star legislation corrected this problem by simply requiring that the CCT be on the package. This practice has carried over to linear tubes as well. I no longer see tubes solely labeled as warm white, cool white, or daylight. These terms still appear on the packages, but so does the CCT.

Someone here once linked to the old and new Energy Star legislation but the search function still isn't working particularly well. If I saved these documents on my hard drive I'll post the relevant paragraphs here.

Now, they have LED's that exactly match incandescent color, but they don't seem to be catching on. You would thin they would immediately take over LED flashlights, but all the ones I've seen use the bluish white.

Which only proves that incandescent was never really ideal, and even less so in something like a flashlight were the crispness of the light takes precedence over all else. I'll go out on a limb here and say that except among lighting designers who can't fathom the idea of people wanting something other than warm light in their homes, warm-white LEDs will continue to be at best a niche market even once LEDs start to take over general lighting. I may be wrong of course, but I'm seeing more and more studies suggesting sunlight-like lighting is actually better for long-term eye health, especially when one does a lot of close work. In my walks I'm also seeing more and more family rooms, dining rooms, etc. lit these days with high CCT fluorescent lighting instead of the traditional warm lighting usually used in these rooms. It can't be that these people are all CPF light connoisseurs. More likely they went through the same things you and I did, and simply found they liked cool lighting better

[Cavannus]

This isn't what Kruithoff's curve tells us at all. Rather, it tells us that at lower lighting levels what is perceived as pleasant will have a lower color temperature than what is considered pleasant at higher lighting levels. [...]

Indeed, you're right... but this is only one way to see the curve. In fact, as you say, on two axes (intensity and light color) the curve means the point where both axes are comfortable. Follow the curve, and you'lle see that I'm right, as you are too! It is also possible to "reverse" the curve and to put "comfortability" on an axis...

From a practical perspective, this means that higher color temperature lighting needs to have higher intensity to "feel" right. Note that this has nothing to do with the light being good for seeing or considered "good light output". [...]

I agree!

The first part of the sentence is correct, but it's a bit stretch to come to the conclusion that "not good" is perceived as "not bright enough". In general, a person will only complain about light levels if they're not adequate for the task. [...]

Believe my ergonomist experience: people are not able to express why a light system doesn't fit with their task. They may complain about the light color or the light quality, even if this is mainly a problem of intensity! They may really say "the light is sad, not very nice, like a old fluorescent tube" whereas it's only a question of light output!

One thing I find very suspect about Kruithoff's curve are the findings at very low light levels even if the findings are fairly valid at higher light levels. [...]

Personally I only interpret this curve in relative terms. Again because psychological effect. For example, for the same perception of sufficient output, more output is expected in a room than in a cave or in the street... In the first case 300 lux are required, in the two other cases, 10 lux are enough...

For me, very low levels are out of scope.

[NewBie]

Check this feat out:

http://candlepowerforums.com/vb/showthread.php?t=107930

[LEDninja]

Check this feat out:

http://candlepowerforums.com/vb/showthread.php?t=107930

An article on those guys. Looks like they are doing ceiling fixtures for now.
http://www.newsobserver.com/104/story/393185.html
54 lumens/watt is impressive. Especially since they are using warm white.
900 lumens for 13 watts measured at the plug.
My '13 watt' compact flouresent is listed 800 lumens on the package. Power usage is 210mA at 120volts or 25.2 watts measured at the plug.
So those LED lamps are almost twice as efficient as compact flouresent with similar output.

LEDmuseum got some bulbs for review.
http://ledmuseum.candlepower.us/fifth/rlbulbs.htm

[jtr1962]

My '13 watt' compact flouresent is listed 800 lumens on the package. Power usage is 210mA at 120volts or 25.2 watts measured at the plug.

The volt-amps are more than the watts because the power factor is less than one. Look at the labels on air conditioners. You get the same thing. If you multiply the volts and amps you end up with a higher number than the labeled rating in watts. Your CFL does indeed draw 13 watts, not 25.2 so its overall wall-plug efficiency is 61.5 lm/W.

[jtr1962]

Believe my ergonomist experience: people are not able to express why a light system doesn't fit with their task. They may complain about the light color or the light quality, even if this is mainly a problem of intensity! They may really say "the light is sad, not very nice, like a old fluorescent tube" whereas it's only a question of light output!

I'm really surprised that adults would use terms like that to evaluate a lighting system. Saying "the light is sad" sounds like something a 5-year old might say. And there's still that negative association of bad lighting with fluorescent despite the fact that the old drawbacks no longer exist.

I also question the methodology some of these lighting designers use for the comparisons. For example, they'll compare an incandescent with a poor color rendering old-style cool white tube on a magnetic ballast and then draw the conclusion that most people don't like high color temperature lighting. Truth is that their own bias towards warm lighting made them set up the test in such a way as to guarantee the outcome they wanted. Try the same test using high color rendering 5000K lamps instead and I beleive the results would be very different. You'll probably get a lot of people say "I like that lamp better. It looks more like sunlight than the incandescent."

Personally I only interpret this curve in relative terms. Again because psychological effect. For example, for the same perception of sufficient output, more output is expected in a room than in a cave or in the street... In the first case 300 lux are required, in the two other cases, 10 lux are enough...

At 300 lux the mean "pleasant" color temperature is actually roughly 4000 to 4500K. Truth is most people light their homes like caves, so more likely lighting levels are closer to 10 lux. I don't consider a 100-watt bulb in a lamp which shades out half the lumens to be adequate lighting, yet a lot of the general public uses exactly that. Maybe with LEDs we'll be able to economically have brighter lighting levels eventually and that will by extension lead to higher color temperatures.

[Opto-King]

http://www.optoga.se/general_newsdet...0pa&lang=en_US

[NewBie]

An article on those guys. Looks like they are doing ceiling fixtures for now.
http://www.newsobserver.com/104/story/393185.html
54 lumens/watt is impressive. Especially since they are using warm white.
900 lumens for 13 watts measured at the plug.
My '13 watt' compact flouresent is listed 800 lumens on the package. Power usage is 210mA at 120volts or 25.2 watts measured at the plug.
So those LED lamps are almost twice as efficient as compact flouresent with similar output.

It is interesting to note that the CRI for these new LED bulbs is 93% vs. 65-82 for most CFLs.

Thats much better.

[Stephen7372]

What does CRI mean ?

[bguy]

Color Rendering Index

Google for "cri lighting" gives me this:
http://http://www.sizes.com/units/CRI.htm

It's a subjective rating for color rendition for lighting sources. Scale of 0-100, 100 being best.

[Handlobraesing]

It is interesting to note that the CRI for these new LED bulbs is 93% vs. 65-82 for most CFLs.

Thats much better.

Reference?

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.

With the 8 ft fluorescent, you can reach ~100 lumens per watt using the best ballast while making around 5,000 lumens per lamp and a CRI of 86.

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

You can get them in 3,000, 3,500, 4,100, 5,000 and other color temperatures depending on market demand and the color is extremely consistent within a lot. From batch to batch, there might be a slight variation, but you really have to look for it to see the difference.

The disadvantage is reduction in life with frequent switching. Cost per lamp is $5 or less in the typical quantity they're used in, which comes to less than a dollar per thousand lumens.

[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/gr...b/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_li...nt/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/Lighti...DS&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_d...ems/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...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_...lbs_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/Railro.../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_...lbs_33_ctg.htm

From Paralite's own page, see down at the bottom for the actual spikey spectrum:
http://www.paralite.com/fluorescent_...e_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:...&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_...e_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]

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]

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]

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]

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]

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/a...btab=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/...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/...f/P-5037-D.pdf

[jtr1962]

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).