Re: ATM Wave Length Foucault Data! :)

["Andrew Schott" <aschott@digital.net>]

True - a white LED will photograph white and for all intents and purposes
will appear white to us trichromatic humans.  My point to the original
poster was since the mirror testing he was doing appeared to be sensitive to
the particular wavelength of light he was using, the white LED would not
give him panchromatic results but more the effect of using two or three
LED's together.  If blue causes mirror surface roughness to be more apparent
and red or yellow tends to smooth the surface out, the white LED will cause
the mirror to respond more like it's being gauged by blue light.  It won't
provide a very good combination of all spectra like a simple tungsten
filament or a ray of sunlight will.  Yes, it will photograph like white
light, and fool you into thinking you're looking at a broadband light
source, but like high pressure sodium light it's a mixture of two or three
extremely narrow spectral spikes and will behave more like multiple
monochromatic sources.   Still, they're fun to play with and that's what
this endeavor is all about.  Who knows, maybe there's some unexpected
property of the white LED that may place it far and above any other type of
light for critical testing in ATM.  I know they're almost as high band as
ultraviolet in the way it excites phosphorescent and fluorescent materials.
Check out the way glow in the dark paint responds and check out an old
blacklight poster with it.


----- Original Message -----
From: Bob May <bobmay@nethere.com>
To: atml <atm@shore.net>
Sent: Wednesday, March 28, 2001 3:21 PM
Subject: Re: ATM Wave Length Foucault Data! :)


>
> Not only is it a cat toy, but kids in the 2-4 year range also have a lot
of
> fun chasing the light and stomping on it.
> The white LED may be putting out only a few colors but if the color camera
> sees it as white and a sunlight card also as white then the color balance
of

<poit>