Wow. A week or so ago, as I sometimes do, I feel asleep wearing my watch. I woke up at some point, and was surprised to see that a watch I was wearing was glowing, faintly. This was concerning, because it was a '50s Timex. Maybe I've been naive, but I have about 15 or so of the Timex 'Marlin' series from the '50s and although the luminous material never glowed on any of them, I had previously assumed they were the non-rad dials and hands, made with the light-activated type of luminous material "glow in the dark", now lost its charm.
I thought, 'these are post-radium pre tritium, they must be a light activated glow in the dark type lume, lost its kick.' For unknown reasons, it never ocurred to me that these may have been radioactive dials. Maybe I thought that by 1953, Timex wasn't using radium? Well, I was wrong! (more below)
I suspected a radioactive radium dial, and hauled in a dozen or so Timex and non-Timex watches, and tested them with a GM counter. Every single one of the '50s Timex with luminous material were hot, though with varying levels of intensity. The persistence of tremendous activity means this is
radium which lasts, effectively, forever. It can't be tritium. I'm not even sure if they had started using Tritium in '53, but in any case if so the Tritium would have decayed down to nil and the dial would have been cold. So after confirming that the dials and hands were hot with the GM counter, I then laid five Timex watches face down on a sheet of x-ray film in the dark, and let them sit for about half an hour, developed the film. You can see the five autoradiographs created. Note in particular the intense activity in the hands, which 'bloom' far beyond the actual boundary of the hands themselves. This was greatest with the 'Dauphine' type hands. The most obviously pretty image is from the black dial Timex auto pictured below. I forgot that most of them were wound and running, which is why the minute hands left a blurred swath on the x-ray. On the pictured watch, you can see that the triangle markers at 12,3,6,9 are less intense than the round markers. What does this all mean? For one, that Timex was using radium on dials in the 1950s. When were these 'officially outlawed' anyway?