@Michael The only instance of warm white mercury I have seen in my life was when I was around 8 years old. In the winter at night we were going somewhere and one of the cobra head street lights was glowing a strange warm white which was in contrast to all the normal mercury and sodium lights around. I do wonder if that was an incandescent lamp. or if maybe someone found an old warm white mercury bulb in the stock room at the maintenance depot. or maybe perhaps it was an extremely overdriven sodium bulb... I suppose we can never know now. 


most of the mercury lights in service back then and currently are a mixture of DX and Clear. there is a couple old color improved lamps scattered around too. lots of BT shaped lifeguards around still too. naturally all the cheap junk mercury fixtures that were built badly from the 2000s have died and been replaced with LEDs. and all the old stuff that someone did not blindly replace for no reason is still mercury/ sodium.

halide is rarer now.