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I.N. Galidakis
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 Posted: Sun Jul 13, 2008 8:31 am Post subject: CRI and FSI |
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The following just occurred to me, but because I haven>t calculated any CRIs
yet, I am not 100% sure about it.
Has anyone figured out a relationship between FSI and CRI?
It looks to me like these two should be very closely related.
Can anyone think of an example of a source with CRI 100 and FSI 0?
Or a source with an FSI 100 and CRI 0?
In general, can anyone think of a source with a CRI of x and an FSI of y, with
|x-y| maximal?
"maximal" in the sense that the two values are different by a considerable
amount, say > 10?
If not, it seems to me that FSI, by definition, _is_ another label for CRI.
What doeth thy ekthperts thinketh?
Many thanks,
--
I.N. Galidakis |
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Don Klipstein
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| Posted: Sun Jul 13, 2008 4:01 pm Post subject: Re: CRI and FSI |
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In article <1215919912.880122@athprx04>, I.N. Galidakis wrote:
[quote]The following just occurred to me, but because I haven>t calculated any CRIs
yet, I am not 100% sure about it.
Has anyone figured out a relationship between FSI and CRI?
It looks to me like these two should be very closely related.
Can anyone think of an example of a source with CRI 100 and FSI 0?
Or a source with an FSI 100 and CRI 0?
In general, can anyone think of a source with a CRI of x and an FSI of y, with
|x-y| maximal?
"maximal" in the sense that the two values are different by a considerable
amount, say > 10?
If not, it seems to me that FSI, by definition, _is_ another label for CRI.
What doeth thy ekthperts thinketh?
[/quote]
I haven>t checked into what the FSIs of triphosphor fluorescents are,
but I would think that they are less than those of other light sources of
same CRI.
In addition, FSI can only be its maximum possible value at a specific
CCT, while CRI can be 100 over a very wide range of color temperature.
- Don Klipstein (don@misty.com) |
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Victor Roberts
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| Posted: Sun Jul 13, 2008 4:40 pm Post subject: Re: CRI and FSI |
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On Sun, 13 Jul 2008 06:31:51 +0300, "I.N. Galidakis"
<morpheus@olympus.mons> wrote:
[quote]The following just occurred to me, but because I haven>t calculated any CRIs
yet, I am not 100% sure about it.
Has anyone figured out a relationship between FSI and CRI?
It looks to me like these two should be very closely related.
Can anyone think of an example of a source with CRI 100 and FSI 0?
Or a source with an FSI 100 and CRI 0?
In general, can anyone think of a source with a CRI of x and an FSI of y, with
|x-y| maximal?
"maximal" in the sense that the two values are different by a considerable
amount, say > 10?
If not, it seems to me that FSI, by definition, _is_ another label for CRI.
What doeth thy ekthperts thinketh?
Many thanks,
[/quote]
I don>t have the time right now to revisit the whole FSI
saga from a few months back :-) but I do not believe they
will necessarily track.
CRI is based on comparing the SPD of the source to eight
specific color samples. It therefore doesn>t "count"
emission at wavelengths that fall between the eight standard
color samples. This is not an issue for conventional, broad
band sources, but there are many cases where the SPD of an
RGB LED system is changed dramatically by moving the narrow
emission band of one or more of the three colors.
The FSI system, for all its faults, is calculated
continuously over the range of visible wavelengths, so it
should not be susceptible to small shifts in the wavelength
of any particular radiator.
--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
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I.N. Galidakis
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| Posted: Sun Jul 13, 2008 11:42 pm Post subject: Re: CRI and FSI |
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Don Klipstein wrote:
[quote]In article <1215919912.880122@athprx04>, I.N. Galidakis wrote:
The following just occurred to me, but because I haven>t calculated any CRIs
yet, I am not 100% sure about it.
Has anyone figured out a relationship between FSI and CRI?
It looks to me like these two should be very closely related.
Can anyone think of an example of a source with CRI 100 and FSI 0?
Or a source with an FSI 100 and CRI 0?
In general, can anyone think of a source with a CRI of x and an FSI of y,
with
x-y| maximal?
"maximal" in the sense that the two values are different by a considerable
amount, say > 10?
If not, it seems to me that FSI, by definition, _is_ another label for CRI.
What doeth thy ekthperts thinketh?
I haven>t checked into what the FSIs of triphosphor fluorescents are,
but I would think that they are less than those of other light sources of
same CRI.
In addition, FSI can only be its maximum possible value at a specific
CCT, while CRI can be 100 over a very wide range of color temperature.
[/quote]
Thanks Vic and Don.
Btw. I have added some CRI values in my Amici document. If either one of you or
anybody else would like to make any corrections, please do and I will consider
updating the values.
[quote]- Don Klipstein (don@misty.com)
--[/quote]
I.N. Galidakis |
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