[NJARC] Fluorescing minerals

[rho.cos3theta at att.net]

Why do you think the colors for a Traffic Signal were chosen as such in the early days when signals were first introduced.

                                    Joe Patay

-------------- Original message from amagoun <amagoun at davidsarnoff.org>: -------------- 


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> Willemite is found only in northern New Jersey and to a small extent in 
> New Mexico. RCA's Humbolt Leverenz used it as the basis for CRT 
> phosphors that were synthesized for mass production, as can be seen in 
> that green jar on display in the David Sarnoff Library next to the 721TS 
> receiver. The human eye is most sensitive to green light, it coming 
> from the middle of the visible spectrum, which is why one of the 
> challenges with red and blue in color TV was to fabricate phosphors of 
> equal brightness for a given electron beam intensity. 
> 
> Alex 
> 
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> Alexander B. Magoun, Ph.D. 
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