I heard some time ago that the upnoting strips in US currency glows different colors under a UV lamp. I was trying to find a list of these colors on the BEA website, but only could find that the new $20’s being released next month will glow green. Anyone have a cite for the other bills?
http://www.moneyfactory.com/section.cfm/4
If you click on each bill, it will tell you all the security features on that bill.
Nitpick: It will tell you some of the security features on each bill. Some other security features are closely-guarded secrets.
Just curious, where did you hear that?
A press release from a few years ago when BEP was announcing one of the earlier rounds of redesigns. They stated that some new security features were classified.
Canadian money has small spots of UV-fluorescent pigments that can be scratched off. Due to mass paranoia about counterfeiting, many businesses have UV lamp ‘counterfeit detectors’. A lot of cashiers have been ordered to check every bill they get, even fives, exposing themselves to UV radiation in the process.
The UV lamps have a hood over them, and the intensity is probably not very high (not even high enough to tan skin…), but I’m concerned that long-term exposure to even low-intensity UV radiation may be harmful. Thousands of people are exposed to these lamps every day; I’m sure at least a few will eventually suffer some kind of injury, possibly eye damage…
Cool. 
I wonder if it’s ever going to be declassified… I love checking security features.
Roches: Eye damage is possible from UV exposure, it’s been known to lead to early cataracts and is linked to macular degeneration. But the harmful effects are mitigated if you look though a glass screen. As long as you’re not looking directly at the UV light, I don’t think you’re getting a huge increase in risk.
Mr. Babbington: Thanks for the link.
Canadian paper currency is very interesting – a lot of the features that look absolutely identical disappear when viewed under different infrared (rather than ultraviolet) wavelengths. Looking at Canadian bills with a CCD camera and a set of bandpass or cutoff filters is kind of fun.
If you have some photos posted anywhere, I’d like to see them. Can you provide a link?
You don’t go outside much, do you?