Giving up the searching for true neon

I use to think that if I concentrated hard enough and compared known neon sources I would be able to identify neon lights just by their shade of reddish orange color. And I've written about this before.


http://tainanchineseclass.blogspot.tw/2010/02/neon-signs.html
http://tainanchineseclass.blogspot.tw/2009/11/neon-everywhere.html
http://mikeess-trip.blogspot.tw/2011/06/searching-for-true-neon.html

Living in one of the older sections of Taipei means that there is still true neon(uses neon gas) versus uses of fluorescent technology and a phosphor coatings. This NOT true neon:

Investigating further, my problem is that the emission spectrum of neon is not a single pure color but a mixture of wavelengths.

So the light we see from a light using neon is a mixture of colors(mostly in the reddish/orange range). By varying the current, voltage and glass absorbency,  all true neon light don't have the same color. And for the fluorescent technology, varying the composition of the phosphor coating let them mimic any color spectrum.

There are only two ways, I know of to be sure the sign is true neon.

1. When the light is turned off, the glass tubes are transparent, i.e. there is no coating of phosphors that implement the fluorescent technology. Here the tubing is transparent(better seen in daylight).  True neon.

2. The sign has to be pretty old to be true neon. The florescent technology is just more efficient. The mercury vapor and phosphor coatings are cheaper than using neon(also more colors are available) and the power requirements are less. So
any modern sign is NOT true neon. These old style Christian crosses are neon, close inspection shows the tubes are transparent.

But there are lots of nonfunctioning neon signs in our area of Taipei, that are just too dangerous to remove, kind of like fossils of a bygone age.

Well it's nice to put this one to bed, even if the result is not what I hoped for.