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Raphion

join:2000-10-14
Samsara
Reviews:
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reply to Mele20

Re: Another Reason to Not Use CFLs...

I agree that newer fluorescent tubes don't have as good a spectrum as the older ones. The older ones I have clearly have a smoother spectral distribution:

Old F40T12DX tube:




Newer F32T8DX tube:



The newer is more efficient, but the large missing bands of spectrum are what compromise the color rendering.


tschmidt
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join:2000-11-12
Milford, NH
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Interesting chart I have never understood fully what the CRI (color rendition index) means and the specific variation. Seems garden variety 32W T8 have a CRI of 78. Have no idea what the CRI of older T12 was.

I recently upgraded all our fixtures from T12 magnetic ballasts to T8 electronic ballasts. Can't say a see much of a difference in color and it is nice having them come on so quickly and no flicker.

I tried a pair of 3000k "kitchen" bulbs but they were so red both my wife an I agree the 4100k cool-white look much better.

/tom



Raphion

join:2000-10-14
Samsara
Reviews:
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Where CRI comes into play is with pigments or pigment mixtures that reflect colors that are in the light source's deadbands. For example, a pigment that admits light primarily around 520nm would appear much darker relative to a pigment that admits light around 545nm in the F32T8 light, while the same two pigments appear the same relative shade in natural light.

The colors seem to change from what they'd be in natural light simply because all the colors of light aren't there for the pigments to "work with".

CRI is largely determined by how complete and smooth the spectral distribution is.



Juggernaut
Irreverent or irrelevant?
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join:2006-09-05
Kelowna, BC
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1 recommendation

reply to tschmidt

One trick I used to do with 4 footers was, use one cool white, and one warm white. Seemed to do the trick very nicely for a daylight type of light.
--
"I fear the day that technology will surpass our human interaction. The world will have a generation of idiots." ~ Albert Einstein


Mele20
Premium
join:2001-06-05
Hilo, HI
kudos:5

1 edit
reply to Raphion

That is neat to see. Thanks.

For close to 30 years, I used Sylvania warm white (hard to get because the size is 36" not 48")- two of them over the bathroom sink which is outside the rest of the bathroom and is the only lighting for two big closets nearby (this is a condo in space conscious Hawaii). Then about two years ago, I went to get two new ones and was sold the new energy saver ones (but I wasn't told that and it is a small mom/pop store that should have told me) also by Sylvania and also "warm" white. They are actually blueish white but not as blue as "cool white" ones. They kill reds and so my clothes when trying to match a new hat with a dress, for instance, at night the two items match. In the kitchen with warm white Westinghouse 4 footers they don't match at all. And the next day by the window they don't match and the color is dramatically different from when I hold them in the bathroom mirror. The color of the clothes/hat in sunlight is MUCH more like that of the Westinghouse warm white 4 footers in the kitchen and if I turn on the overhead three 100 watt bulb ceiling light then I have color almost the same as sunlight. The ceiling bulbs are incandescent.

So, I really dislike the new Sylvania warm white 36" and I tried the new energy saver Sylvania "warm white" 4 footers in the kitchen too. I used the old Sylvania "warm white"there for over 30 years. I had to return them as the color for "warm" white was way too blue. I have one cool white Sylvania 4 footer that a plumber left one time thinking I used cool white so I put it away for emergencies. I got it out and tried it on one side of the kitchen and the "warm" lower energy Sylvania one on the other side. They were both cool not at all warm. So, I went to Home Depot and I could easily tell from their lighting board demo that the warm Westinghouse that I had never used were warm. So, I bought two 4 footers. Installed them and they are warm but not as bright as the old non energy saving warm white Sylvania. Sylvania did a poor job with their energy saving ones in warm white as those are bluish and not as strong a light either.

I can see from the black at the ends of the bathroom ones that they will need replacing soon and I don't know where I will find warm white 36" that actually are warm. I know Home Depot has that size in cool white but I don't know about warm white in that length.

During a brownout do the CFLs work at all? The long 36/48 inch fluorescents barely come on and constantly flicker so they are worthless during brownout. The incandescents are fine in a brownout. They just give about 1/4 to 1/3 less light but they turn on and don't flicker and you can use them. You cannot use the tube fluorescents during brown out. I have no CFLs that are designed to replace incandescent light bulbs and I am wondering do those work during brownout? We just had a one hour brown out and I would have hated to have no light if all I had was CFLs or fluorescent tubes.
--
When governments fear people, there is liberty. When the people fear the government, there is tyranny. Thomas Jefferson



SparkChaser
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Downingtown, PA
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reply to Raphion

said by Raphion:

Where CRI comes into play is with pigments or pigment mixtures that reflect colors that are in the light source's deadbands. For example, a pigment that admits light primarily around 520nm would appear much darker relative to a pigment that admits light around 545nm


Your explanation of the peaks in fluorescence are correct except that the color result is reversed. Pigments absorb light not emit it. The color is the area in the spectrum where the pigment doesn't absorb.
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--
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"Facts do not cease to exist because they are ignored." - Aldous Huxley


tschmidt
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Milford, NH
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reply to Mele20

said by Mele20:

During a brownout do the CFLs work at all? The long 36/48 inch fluorescents barely come on and constantly flicker so they are worthless during brownout. The incandescents are fine in a brownout. They just give about 1/4 to 1/3 less light but they turn on and don't flicker and you can use them.

That must be one heck of a brownout.

I just swapped out our T12/magnetic florescent light with T8/electronic ballast. The GE ballasts I used are rated for a wide voltage range, 108-305V. Not really for brownouts but so one ballast can be used in multiple locations.

/tom


cowboyro
Premium
join:2000-10-11
Shelton, CT
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reply to Mele20

said by Mele20:

During a brownout do the CFLs work at all? The long 36/48 inch fluorescents barely come on and constantly flicker so they are worthless during brownout.

During a brownout you should switch your power off. From the panel that is. Low voltage may kill devices with switching supplies and motors (pretty much all these days). It may kill TVs, CFLs, refrigerators, air conditioners, furnaces...