Would like to get some insights from the more experienced collectors here. The more obvious signs are, color and even application. But some of the better relumes do that well. I have noticed that some dials have a slight halo around the plots under a loupe. An area of shiny around plots of a matte dial. Is that a sign of a relume? Other things you look for?
Not sure how it works with radium but I find exposing tritium dials to a camera flash useful. It excites the paint and for a minute or so the plots light up. This lets you see any dark areas which may well have been touched up with paint. The uniformity of the glow (or lack thereof) also highlights any areas which may be non original.
learned this from @woodwkr2 - use a uv flashlight. Works with both radium and tritium. should reveal whether or not the lume is uniform, whether or not the color is the same to the naked eye