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In article <1h5ehoINN707@cronkite.Central.Sun.COM> pstryjew@colsun.Central.Sun.COM writes:
->
->How does the human eye perceive "Neon/Florescent" color (i.e. hot pink, blaze
->orange, the Crayola Florescent Crayons)?  
->
->I assume it has something to do with absorption of UV light, but where in the
->spectrum do they reside?  Are they hiding in the "visible" spectrum?  How are
->the dyes made, I can't make them with additive mixing of the three primaries.
->

I believe they are made by mixing normal dyes with a fluorescing substance
such as phosphorous. Thus it appears that it reflects more light than is
incident on it (actually, it's just convering invisible radiation to light).

-- Race Dowling

Pete Stryjewski (pstryjew@colsun.Central.Sun.COM) wrote:

>How does the human eye perceive "Neon/Florescent" color (i.e. hot pink,
blaze
>orange, the Crayola Florescent Crayons)?  

>I assume it has something to do with absorption of UV light, but where in
the
>spectrum do they reside?  Are they hiding in the "visible" spectrum?  How
are
>the dyes made, I can't make them with additive mixing of the three
primaries.

>I haven't been able to get an answer to this question for years (well, I
just
>asked a couple people, that is the extent of my research).

>Answers/Ideas?

My understanding is that these colours actively floresce in the presence of
the UV in natural light, you can't expect to reproduce their properties with
any mix of conventional dyes.

I believe similar stuff is put in washing powder to make your wash "whiter"
and "brighter" [than what one wonders...].

--
Geoff, Sysop Equinox (equinox.gen.nz) +64 (3) 3854406 [4 Lines]
                               Voice: +64 (3) 3852101
        "Hi. You have just entered the fourth dimension. Small isn't it?"

In article <1h5ehoINN707@cronkite.Central.Sun.COM> pstryjew@colsun.Central.Sun.COM (Pete Stryjewski) writes:

>How does the human eye perceive "Neon/Florescent" color (i.e. hot pink, blaze
>orange, the Crayola Florescent Crayons)?  

>I assume it has something to do with absorption of UV light, but where in the
>spectrum do they reside?  Are they hiding in the "visible" spectrum?  How are
>the dyes made, I can't make them with additive mixing of the three primaries.

>I haven't been able to get an answer to this question for years (well, I just
>asked a couple people, that is the extent of my research).

When a high energy foton, such as a UV wavelenght foton hits an electron in an
atom, the electron usually absorbs at least a part of the fotons energy, by
taking a "higher" orbit around the nucleus. Usually, this high energy state
doesn't last very long, and the electron drops back into it's normal orbit,
releasing the just absorbed energy. If the amount of absorbed energy was in the
visible wavelenght spectrum, you can see the foton emitted.
So, the fluorescent colors look brighter than they should in the lighting,
because they show not only the visible light falling on them, but also drop
a portion of the UV lights energy level to a visible wavelenght.
If the above sounds difficult, remember that energy and wavelenght are just
about the same thing. The higher the frequency, ie. the shorter the wavelenght,
the more energy it contains.
--
Osma Ahvenlampi  -  oahvenla@snakemail.hut.fi   * Workstation power for micro-
All my opinions are not necessarily really mine * computer price: Amiga := FUN