CCFT versus LED [was: Spectros better than colorimeters for monitor profiling?]
CCFT versus LED [was: Spectros better than colorimeters for monitor profiling?]
- Subject: CCFT versus LED [was: Spectros better than colorimeters for monitor profiling?]
- From: Marco Ugolini <email@hidden>
- Date: Sat, 25 Oct 2008 15:59:49 -0700
- Thread-topic: CCFT versus LED [was: Spectros better than colorimeters for monitor profiling?]
In a message dated 10/25/08 2:53 PM, edmund ronald wrote:
> ROTFL :)
> LEDs are quantum devices. The simples ones just emit one single
> spectral ray. That's why we even have LED lasers.
> It's harder to be spikier than that.
> Some LEDs have a fluorescent shell encapsulating the actual diode, I
> think this can turn them into white light LEDs, but the light here is
> re-emitted.
Edmund,
If the following graph accurately reflects the typical emissions of
phosphor-based white LEDs, their spectral output is nowhere as spiky as that
of CCFTs:
<http://en.wikipedia.org/wiki/Image:White_LED.png>
More on the subject (with emphasis on the ending statement in the quote):
<http://en.wikipedia.org/wiki/LED>
> Light quality: Most white LEDs have spectra that differ significantly from a
> black body radiator like the sun or an incandescent light. The spike at 460 nm
> and dip at 500 nm can cause the color of objects to be perceived differently
> under LED illumination than sunlight or incandescent sources, due to
> metamerism, red surfaces being rendered particularly badly by typical
> phosphor based LEDs white LEDs. However, the color rendering properties of
> common fluorescent lamps are often inferior to what is now available in
> state-of-art white LEDs.
A quick review of spectral graphs shown at the following URL makes the point
quite well about the superior smoothness of LED light when compared to CCFTs
(yes, there is some spikiness in LEDs, but *comparatively* they seem to
represent a marked step towards improved smoothness):
<http://ledmuseum.home.att.net/spectra7.htm>
Also review the fluorescent spectra on this page (scroll halfway down):
<http://en.wikipedia.org/wiki/Fluorescent_lamp>
Marco Ugolini
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