RE: Measuring "standard IT8.7/4 Random" on iSisXL using ColorPort 2.0
RE: Measuring "standard IT8.7/4 Random" on iSisXL using ColorPort 2.0
- Subject: RE: Measuring "standard IT8.7/4 Random" on iSisXL using ColorPort 2.0
- From: Roger Breton <email@hidden>
- Date: Sat, 22 Jan 2011 10:40:22 -0500
OK, I rest my case, Graeme, not much energy below 400nm, which, effectively
makes these WhiteLEDs "UV-poor" or "UV-devoid" or "UV-depleted" or
"UV-starved" or "UV-missing" kind of light sources but I realize that
sticking with "UV-cut" terminology as a descriptive term is meaningless.
"UV-cut" only makes sense when some part of the spectrum is physically
absorbed. Here, there's no absorption involved but rather a "hole" in the
spectrum, making these white LEDs discontinuous spectral devices. And we're
stuck with these for a long time...
Thank's Graeme for straightening me up.
BTW, would you have a quick and dirty algorithm up your sleeves, in Argyll,
for smoothing out the kind of spectrum shown in
http://www.kolumbus.fi/michael.fletcher/wht_led.gif>?
Roger
-----Original Message-----
From: colorsync-users-bounces+graxx=email@hidden
[mailto:colorsync-users-bounces+graxx=email@hidden] On
Behalf Of Graeme Gill
Sent: January-21-11 11:52 PM
To: undisclosed-recipients:
Cc: 'ColorSync'
Subject: Re: Measuring "standard IT8.7/4 Random" on iSisXL using ColorPort
2.0
Roger Breton wrote:
> But according to the graph, there is still some light energy below 400nm?
I wouldn't take that graph to literally. Perhaps the measuring instrument
wasn't zero'd (ie. it's suspicious how flat the residual level is.)
See also:
<http://www.trainweb.org/girr/tips/tips7/white_led_plot.jpg>
<http://www.ecse.rpi.edu/~schubert/Light-Emitting-Diodes-dot-org/chap21/F21-
08 Spectrum white P LED.jpg>
<http://qubitsystems.com/wp-content/uploads/2010/04/LED_spectrum.jpg>
<http://www.kolumbus.fi/michael.fletcher/wht_led.gif>
Graeme Gill.
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