Off topic, but ~40 years ago I was at school with a boy called who had a luminous watch which sent the Geiger Counter crazy in Physics class. The teacher got very worried as the counter didn't even have to get near this watch for it to start clicking away loudly, and when it was right next to the watch it screamed out a continuous high-pitched noise, very loud indeed.
They told him he couldn't wear the watch any more as it was dangerous - he was annoyed because he had inherited it from his grandfather. On his wrist under where he wore the watch, he had burn scarring and angry red welts. I have no idea what it was that was used in the luminous paint, but it certainly wasn't ordinary GITD powder - for all I know it must have been Plutonium or something.
I don't know what happened to the boy - I haven't seen him since leaving school. His name was Woodcock. We called him Timbertool.