To you, do they all seem too dim?
They say it uses only 15 watts or whatever but puts out 100.
They are really dim to me.
Any brands not dim?
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Yes, they all have that subjective dimness. It could be that they're going by photometric measurements that count the two narrow green spectral spikes from the mercury vapor that the human visual system has to discard in order to adapt to flourescent and see reasonable colors.
-- J.S.
John it is the phosphors.
Here is message posted in Woodnet forums by Jack Lindsay, a retired lighting engineer.
"Bill,
Thanks for your kind comment.
I'd like to expand on your comment about the perceived brightness of high CRI lamps. The concept actually has its roots in research performed in the early 1980's by Bill Thornton, an engineer for Westinghouse Lighting.
But first it is necessary to briefly discuss the human visual system. Please bear with me if you already know this but I'm sure that not all readers are familiar with it.
The human eye contains two sets of photoreceptors (cells that respond to stimulus by light). These are called "rods", and "cones". Rods are responsible for vision under low levels of light such as moonlight, while cones respond to stimulation at higher levels of illumination. Rods respond only to low-level stimulus and cannot perceive color. That is why we don't see different colors at low lighting levels.
Cones respond to higher levels of light, and are the color receptors. There are three sets of cones, each responding to a different color: red, green, and blue. Cones do not react uniformly to all wavelengths within a color. Their sensitivity varies according to wavelength, with each color peaking at a specific wavelength. For example, the blue cone has a low sensitivity at about 400 nanometers (violet) but rises rapidly to a peak at about 450 nanometers (bright blue), and drops rapidly to nearly nothing at about 550 nanometers (green/yellow). The green and red cones have similar curves in the green and red zones, respectively, and the red cone has a secondary but much lower peak in the blue region. The bottom line: we don't see all colors equally. There are peaks in visual sensitivity at specific wavelengths (colors).
Thornton theorized that a lamp that utilized phosphors that had their peak outputs in the same regions as the peaks in sensitivity of the three color receptors would be perceived as being brighter, and colors would appear brighter. He was right, and a new family of tri-phosphor lamps was born. Bill's name for them was "Prime Color" since they were based on the primary colors of light.
Over the years the phosphors have been improved but the concept remains unchanged. The lamps are now called "Rare Earth, or RE Phosphors, but they have their roots in the original tri-phosphor lamps based on the tri-stimulus eye sensitivity curve.
As a not of interest, color blind individuals generally prefer the standard phosphor lamps since their visual systems are deficient in one or more color regions and the eye doesn't blend the colors of light in the same manner as an eye with normal color vision.
Bet that's more than you really cared to know about the subject."
Most of the CFL's that I have seen have realitively high CRI (80-85). Where as the cool white/warm white have CRI's in the 60-70 range.
I noticed huge increase in apparent brightness in my shop when I replaced my cool whites with SPX series tubs.
I think that there are a couple of things going on with the CFL's. First I suspect that they are pushing the "equilant" ratings. The other is that incandenscent have a more destinct light source where the CFL is spread around the bulb.
> it is the phosphors.
The phosphors are the thing the lamp makers can vary and control. The quantum spikes caused by electrons jumping around in the mercury atoms are something they're pretty much stuck with. The blue line at 435.8335 nanometers and the green line at 546.0750 nm are each a good eight times brighter than the phosphors over an equivalent passband anywhere in the visible spectrum. They use mercury because most of its energy is in the ultraviolet, mainly the 253.6521 nm line, which beats the problem lines by about 30 to one. It's the UV that powers the phosphors.
Photographic film certainly sees the blue and green mercury lines in flourescents, and represents them using dye primaries that cover bands over 100 nm wide. Somehow our eyes and brains are able to discard the narrow spikes in the real world, but not the wide band blue-green we see in pictures and in video.
So, a purely physical measurement that counts the spectral lines would give you a higher value than one that dropped them and only counted the phosphors.
-- J.S.
I bought three of the screw in kind for a light that stays on all the time.. They did not last more than 3 or 4 months,seemed real expensive for that little time...Been using those 40w round things for bath fixtures and they last a couple years...
I have had bad experices with some cheap ones such as Lights of America.
But I have a pair of 28watt panasonic units that are mounted outdoors ona pole with a photocell. The first set lasted 3 years and then only one failed and when I took it apart it was a mechanical failure, possibly caused when I hit the pole with the arm on an excevator.
I use them in my kitchen and I love them,but the fixture takes 4 bulbs. To me they only seem dim as the heat up to temp, or I've just got used to it. Either way just wait a few years and there will be better ones than now. I remember the first ones that came out were not much better than office light, now at least they look similare to reagular icandesents.
Jason
Yes, they often seem dimmer than the "equivalent" incandescent. There are two reasons for this:
1) It takes about 5 minutes for the fluorescent to achieve full brightness. Prior to that it will seem strangely "brown".
2) The manufacturers habitually overstate the brightness of the fluorescents.
I generally replace an incandescent with one size larger fluorescent. Ie, replace a 60W incandescent with an "equivalent to" 75W fluorescent. This seems to get the job done.
I started buying CF bulbs well over 10 years ago and they've come a long way.
The latest best buy has been at Target.
4 pack packages of GE Soft White 100 bulbs for $15.
26 watt 1650 lumens rated for 6000 hours.
$15 and more is what I used to pay for the dim and unpleasant early generation bulbs that were rated at only 15 watts, and I still have some of them (but not using.)
The current crop of CF bulbs are noticeably brighter and whiter and nearly instant-on.
Wow, 1650 lumens ! I bought the GE bulbs and they were 14W and only 800 lumens (more than 5% short of the incandescents they're slowly replacing). But these are in closets, the laundry romm etc., so it's a who cares - most of the lights in our home use multiple candelabra-base bulbs (in two different sizes, each of 2 different shapes, and all in 3 different wattages); and little chance of a glow-light replacement..
Phill Giles
The Unionville Woodwright
Unionville, Ontario
My outside floor lightes are Panasonic 28w/1680lumen.
You can get round and D-shape ones upto 55w/3900 lumem
And a conventional (for CFL) Philips 34w/2100 Lumen.
Also LOA has a 42w/2700 lumen, but as I have mentioned I don't trust that brand.
http://www.energyfederation.org/consumer/default.php/cPath/25_44_167_786
re - Wow, 1650 lumens !
----
well, i must confess i don't understand these figures except it being higher the better.
however, i can certainly tell the difference in brightness.
the 26W GE bulbs are more compact and shorter then the 27W rated models from several years ago.
and when they come on, it is nearly instantaneous and basically at their maximum brightness.
the color temperature is also a lot whiter/brighter thus more pleasant then the dull yellow regular bulbs or the sickening color of the earlier generation CF bulbs.
and they are truly as close as i have seen them come to the brightness of a regular 100W bulb, maybe brighter.
i have compact flourescents in nearly all fixtures in our house and another house we own.
they are excellent for leaving on for extended periods when the house is empty.
there are five entry way soffit lights that has been burning for several years all night. every night.
anyway, attached is a picture of the bulb and the 4-pak i've been buying from Target for $15.00, which is a deal i haven't found anywhere else including Sam's Club and Wal-Mart.
I'd love to have more compact fluorescent lights in use in our house. Unfortunately, they aren't quite compact enough. The compact "60W" units are really the size of a 100W incandescent and won't fit in many of our fixtures. And several of our fixtures are dimming and the dimmable CFLs are even larger (and a lot more expensive).
As it is, we have them in one table lamp, the lights in the entry way (which are hard to reach so the reduced frequency of change is a big plus), one bathroom, and the utility room. Don't have them in the bedrooms, the family room, or the dining room -- the big lightbulb users -- due to size/dimming problems.
I understand your dilemma, which I have run into.
But as the picture shows, the higer wattage units have shrunk considerably over the years.
As I discover newer more compact bulbs, they are fitting in fixtures that couldn't take advantage of them.
Case in point are the outside soffit lights, which couldn't accomodate the older longer bulbs.
The bulbs in the picture fit without protruding past the cover lens.
Used to have an older CF light in a hallyway light fixture with about a third of the bulb protruding past the shade.
The newer ones fit inside the shade.
Also, there were some fixtures that wouldn't take the bulbs with the fat ballast base that you see on the Lights of America bulbs.
The newer GE/Philips/Sylvania ones with the tapered base fit many more sockets/tapered shade combinations.
Anyway, at under $4/bulb, it's a deal that can't be passed up whenever Target has them on the shelves.
These TCP look fairly compact. Have not compared them to an A bulb to see how they compare.
http://www.energyfederation.org/consumer/default.php/cPath/169_205
I haven't checked every model and style, but I've yet to find a CFL bulb (even non-dimmable) that's the same length as the "equivalent" incandescent, especially since I prefer to "size up" one size for true equivalent brightness.
Most of my fixtures are of the globe variety, and a too-large bulb simply won't fit.
They are getting closer.
I can't use CFLs outside because this is Minnesota and they don't work too well in the winter. Besides, our two main outside lights require those "flame" bulbs.
You're right. It's difficult to find a compact fluorescent that will operate outdoors. The packaging is misleading, too. They say "outdoor" in bold letters on the front of the package, then in fine print on the back they say they are only rated down to -25°F or something like that.
In my experience, though, when installed in a fixture they warm up a bit after being on for a few minutes and do put out enough light, even if not full brightness. If you have a fixture that holds multiple lamps you can put in one low wattage long life incandescent to guarantee some light and provide enough heat for the fluroescent to work well.
they are only rated down to -25°F or something like that
Who cares if the lights are on if it's -25 out there?
Not me, I ain't going out.
Joe H
"-25ºF" ?! Gosh, the GE's have a warning on them that they may not start below 32ºF (0ºC)..
Phill Giles
The Unionville Woodwright
Unionville, Ontario
Pet peeve with these... our utility company started handing them out and giving coupons for discounts on them, without ever recognizing that some of them contain significant quantities of mercury (something we're trying to keep out of landfills and bodies of water). They should be recycled, not landfilled, but the packaging doesn't say that, and neither do the utility companies.
Sorry. I'll get off my soapbox now.
Have you seen the new "sunlight" lamps? I got one and so far it seems good--bright for its low wattage and seems to give truer colors. Expensive though.
Yeah, Ott and TruColor are brands for this, I believe. They contain a more complex mix of phosphors that produce a more uniform color spectrum. But Ott especially is very expensive.
I agree.
My rule of thumb is to use one size larger than what they recommend on the package. If you want 60 watt equivalent use what they say is a 75 watt equivalent. The price is similar and the savings still substantial.
I will say it is more important to follow this rule with cheaper discount units. I suspect that these units are being less rigorous in their ratings. The higher end name brand units seem to be more conservative in their estimations so you can often use their ratings as printed.
You can see the same general effect with cheap power tools horsepower ratings. They tend to be exaggerated, referring to 'developed horsepower', while name brand commercial units are closer to actual truth and a fairer estimation of actual performance.