Welcome to Connecting to Collections Care › Forums › Group Forums › C2C Community Archives – 2012 through 2014 › c.1915 "Glow-in-the-Dark" Postcard-Hazard? › Reply To: c.1915 "Glow-in-the-Dark" Postcard-Hazard?
I was able to find snippets of some french articles that suggest that Zinc sulfide may have been used.
I think RAD stands for Radiana, which was either a company or the trade name of the paint/process. I believe it to be different from the Radiana trademark used in the US for “radium gowns” described here http://query.nytimes.com/mem/archive-free/pdf?res=F30811F83F5D1A7A93C7A9178DD85F468285F9
see also this french article, illustrated with photo postcards that also glow