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self-ballasted CFL bulbs


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#1 Steven Carubia

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Posted 27 January 2011 - 12:40 AM

I've done some digging on the forums for information on self-ballasted CFL bulbs. I haven't found a straight answer as to whether these globes flicker or produce a green spike. I suspect that the answer varies by brand. I've attached a picture of the globes that are readily available to me. They seem high quality, though the dimming feature is weak. Information and suggestions are welcome.

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Edited by Steven Carubia, 27 January 2011 - 12:44 AM.

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#2 Steven Carubia

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Posted 27 January 2011 - 12:45 AM

Sorry, I don't know why the picture is upside down. It happened when I uploaded it.
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#3 Ari Schaeffer

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Posted 27 January 2011 - 09:38 AM

CFL bulbs vary wildly. A lower CRI rating will mean that it will spike green for sure and you'll need -G correction (magenta)...sometimes the CRI is high but the actual glass is slightly tinted green so you'll still get a green cast.....It's crazy how long CFLs have been around now and yet there's still such variance.

I would just look at them at 5600k in camera if you don't have a color meter.
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#4 Adrian Sierkowski

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Posted 27 January 2011 - 11:42 AM

I've had some which work well, and others which don't. I've never noticed a flicker in normal temperature ranges, but I do notice that the CFLs on my outside light at home have "trouble" when it's too cold... so I'd not recommend using them outside in the winter.
To test for green spikes ect, a digital video or stills camera can shot that kind of information, and I have noticed that sometimes It'll vary bulb to bulb.
One of the ways I prefer to us CFLs are in chinaballs, as I can use brighter lights with less heat in smaller china-balls and, if need be, i can throw -G on them pretty easily.
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#5 John Sprung

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Posted 27 January 2011 - 03:52 PM

Flicker, mostly not, except as noted in the cold, or as they reach the end of their life.

Green, mostly yes. It's inevitable in flourescents because it's in the spectrum of the mercury vapor that drives the phosphors. They all overdrive the phosphors, saturating them and a little more, to get a constant output. That'll vary with voltage and temperature, so the amount of extra green in that narrow spike, the height of the spike, is random.




-- J.S.
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#6 Steve London

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Posted 01 February 2011 - 12:05 PM

I've used the Home Depot 5600K house brand for years in China balls and not had a problem anyone complained about although the green has to be there. Skin tones have been rendered quite attractively.

I like the CFLs because I can put daylight in the lantern and get a usable amount of of light with low temperature and no worries about fire.

I used to use three Y-adapters screwed together so I could put up to four globes in the fixture, controlling the output by the number of globes screwed in but have since found some adapters that give me four sockets from one Edison base, so a little tidier and tighter than all those Y adapters.

Home Depot used to list CRI on their packaging but no longer. I've also often found there is more info on the ballasts of the globes than there is on the box. Manufacturer or distributor websites are often useful too.

I don't think a color temperature meter is terribly useful with these things because of their spiky discontinuous spectrum but still and movie camera tests tell the tale.
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#7 Steven Carubia

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Posted 02 February 2011 - 02:30 AM

I've just learned that the CFL I posted a picture of has a CRI rating of 82. Does that help narrow your responses?
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#8 Steven Carubia

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Posted 02 February 2011 - 02:38 AM

This product also claims to have a color temperature of 2700K (accurate?) if that has any bearing on green spikes.
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#9 Hal Smith

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Posted 02 February 2011 - 04:59 AM

This product also claims to have a color temperature of 2700K (accurate?) if that has any bearing on green spikes.


No, the green spike is generated by the green spectral line in the mercury vapor arc that is the electrical basis of operation of a fluorescent. It "leaks" through the phosphors on the inside of the glass envelope.
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#10 Stuart Brereton

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Posted 02 February 2011 - 02:38 PM

I've just learned that the CFL I posted a picture of has a CRI rating of 82. Does that help narrow your responses?


A CRI of 82 is not particularly good. Generally, you would want >90. That said, all cameras differ in their response to the green spike, so you may get away with a lower CRI.
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#11 John Sprung

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Posted 02 February 2011 - 02:45 PM

CRI is defined in terms of human visual response, and is kinda bogus at that. You really have to test to know for sure.





-- J.S.
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