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-----Do Cadmium rust compounds glow orange/pink in UV?
Q. So I have this old Olympia SM3 typewriter and someone on Reddit said that if you put it under UV it glows a pinkish orange. ChatGPT is telling me its not cadmium but rust particles and zinc, but Google's AI is telling me it is.
I'd like to know what anyone would think here about these pictures I am attaching showing some of the rust. I have that glow almost all over a lot of parts. I/m kind of surprised it would have that much cadmium, so I tend to want to believe ChatGPT.
Olympia Typewriters on eBay (affil link)Ty Pangburn
hobbyist - Denver Co
December 1, 2025
A. Hello Ty,
It is highly unlikely that is the CADMIUM itself glowing.
It is most likely, dirt, oils, or other materials on the surface that fluoresce, or trace elements in the plating/base steel.
NDT = non destructive testing
We do NDT with a black light and the CADMIUM doesn't glow.
Ruben Ramirez- Grand Junction
A. Cadmium Sulfide is fluorescent. And sulfides are in the air (that's why silver turns black). Even so, I doubt that it is Cadmium because I can think of no rational reason why Cadmium would be used in such an application.
Tom Rochester
CTO - Jackson, Michigan, USA
Plating Systems & Technologies, Inc.
January 10, 2026
These Olympia typewriters are from the 1950s when the toxicity of cadmium wasn't widely recognized. And cadmium plating does have some nice advantages over zinc plating, so it wouldn't surprise me if the keys were cadmium plated.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
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A. On further reflection, my best (new) GUESS is that the fluorescence comes from Zinc Sulfide. (Early in my career, when I introduced a new product to a potential customer, he told me to 'go back to the lab and GUESS again.')
Tom Rochester
CTO - Jackson, Michigan, USA
Plating Systems & Technologies, Inc.
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