This seems to be an utterly confused discussion. There is no indication that the vase that started this discussion is, in fact, from the 1930s, or that the ash tray which turns out to be a cigarette box is from that age. The introduction of Uranium has been pretty well documented (Riedel, 1830 - but that is an entirely different discussion) and so has the introduction of Neodymium (Moser, 1928). In both cases the technique spread to many other companies within months, not years, and any assumption on who produced or did not produce colours or variations thereof will have to remain just that. We have a starting date, so we know it cannot have been produced before that time. But that is all it proves.