In <Xns9CA6C981F59B9SntzldfrdSntzldfrdco@216.196.97.1 42>, S. Austin wrote:
>"JB" <(E-Mail Removed)> wrote :
>
>>
>> "Sarah Austin" <(E-Mail Removed)> wrote in message
>> news:Xns9CA5EAEAE9AACSntzldfrdSntzldfrdco@216.196. 97.142...
>>> Victor Roberts <(E-Mail Removed)> wrote :
>>>
>>>> On Wed, 14 Oct 2009 21:46:08 -0500, Sarah Austin
>>>><(E-Mail Removed)> wrote:
>>>>
>>>>>We're switching over from incandescent to 27 watt dual 5100k or
>>>>>5500k CFL's in the various rooms of this modular house.
>>>>>
>>>>>These CFL's specify that a fixture be open, though, so as not to
>>>>>have a heat buildup, I suppose.
>>>>>
>>>>>
>>>>>The fixtures we have now are like this:
>>>>>http://images.become.com/imageserver...0-175-150-5-0/
>>>>>
>>>>>clear ribbed bowl lights, but closed.
>>>>>
>>>>>We'd rather not have to buy all new fixtures for the whole house,
>>>>>so I was wondering if there were clear ribbed glass plates that we
>>>>>could replace the bowls with, that would make open fixtures out of
>>>>>the existing ones, and would let as much of the light out, as
>>>>>possible, too?
>>>>>
>>>>>Even if they had something like a clear glass plate with leafed
>>>>>patterns on it, and a hole in the middle to mount under the CFL's,
>>>>>it would be great, but I cant find anything like that.
>>>>>
>>>>>Suggestions?
>>>>
>>>> Why are you switching to 5100K or above? Is this a decision
>>>> you made after studying different color temperatures, or was
>>>> this suggested or mandated by someone else?
>>>>
>>>> The incandescent lamps you are taking out have a color
>>>> temperature of about 2700K. 5100K is close to the color
>>>> temperature of the sun, and most people find that a lamp
>>>> this "blue" make skin tones look terrible.
>>>
>>> It's full spectrum though, right? Most natural?
>>>
>> Sadly they will be nothing remotely like 'full spectrum'. I do so
>> hate that term when applied to fluorescents.
>> JB
>
>Even Vita-Lites?
"Full Spectrum" has no definition accepted by any significant industry
standards organization.
Meanwhile, "Vita-Lites" are high-CRI flatter-spectrum halophosphate
lamps, with CRI around 91 IIRC. I do think of those as "full spectrum".
I would prefer "850" color triphosphor lamps such as Philips Ultralume
5000, whose CRI is 84 IIRC, for 3 reasons:
1. The "Vita Lites" and similar lamps have light output being
significantly compromised, while "850" lamps do not.
2. The color distortions of the "Vita Lites" and similar lamps, although
generally small, are mostly in the direction of making colored objects
appear darker and duller.
3. Major-brand triphosphor lamps cost less than specialty brand extra-
high-CRI ones and specialty brands that tout "full sectrum".
Meanwhile, if overall color of the light is matched and
scotopic/photopic ratio is matched (in this case they will be close),
then all known photoreceptors in the human eye will be stimulated in
roughly the same ratios by both lamps. The likely-existing cirtopic
receptors will be stimulated a little less by triphosphor light than by
an equal amount of halophosphate light of the same color, but it appears
to me that the triphosphor will outweigh this due to producing more light.
And, the need to stimulate the likely-existing cirtopic receptors,
and how much need there is, is still under debate. Meanwhile, I would
not pay extra for health claims of "full spectrum" lamps.
And in the likely event high color temp. lamps in home use achieves a
"stark" or "dreary gray" effect, I would use ones of lower color temp.
(3500K or less) despite making the light less like that of "natural
daylight".
- Don Klipstein ((E-Mail Removed))
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