Maybe an unpopular opinion but I always adored color shifted MV and MH lights. 

I remember as a kid, looking out the window at night and looking at all the different coloured MV lights on those old Powerlite Gumballs streetlights.

It was always cool to see on high bay lights too, but I hear they try to replace them all simultaneously with the same brand if one is burnt out to avoid that effect.


Does anyone else just find it super pretty?

We had MH low bays in the main hall in high school, it was always one reason you could tell they were all MH, as they all had different ‘tints’ of red and blue in them!   
Can’t say I’ve ever seen it with MV though?, we had a supermarket called Fine Fare when I was a kid, lit entirely by 1000 watt MV, and as I remember, colour uniformity was excellent throughout the whole store, which also suggests they were bulked re-lamped together?

They sure have something that makes them stand out.

Especially mercury lamps, since they seldom completely fail. They'll get dimmer and dimmer. At extreme levels they basically become high-power decorative lamps    And their colour is something you just won't get with coloured lamps made for that purpose.

Oh, yes, I do. Greened out mercury lamps are very interesting to me. There used to be an old MV day burner on my way to and from work, and I would always look at it to see what shade of green or greenish white it appeared. It was interesting to see how its appearance would change (=the degree of "greenness") with different weather conditions. It would be at its greenest on sunny days when I would wear brown tinted sunglasses. At night, you could barely tell it was greened out.

Another cool effect now gone were the lights in the skating arena at my alma mater. They were 1000W probe start MH. A couple of the fixtures had the lamps slowly oscillating between redder and bluer light. The cycle lasted about one minute. If you stood still, you could see the changeover, kind of the effect that a very thin cloud has when it passes under the sun. Those lights were replaced with fluorescent, but they reappeared in the swimming pool, with the same effect. Unfortunately, they are now gone. It was the fixtures that were responsible for the cycling as when they were put in the pool, they all had new lamps and the effect was visible.

Yet another cool thing was rows of MH track lights in supermarkets. For some reason, they seemed to escape the group relamps. There was the odd greened out one which was cool.

There were quite a few malls and buildings here with MV recessed downlights with varying degrees of maintenance so I saw quite a few places with colour shifted MV cans next to a freshly relamped one. Some of these still remain to this day with the lamps are varying degrees of brightness/greenness.

Interesting!


I’ve seen some colour shifted lights that would have a more pinkish hue, and some that were more warm white/almost beige.


Can mercury lamps develop a pinkish hue with age or any other colours depending on the phosphor?

Or are you more likely to see more diverse colour shifting on metal halide?

Not at all. My school has a bunch of 2x4 troffers, and 90% of the time, more than one color temperature is seen in the same room. I like everything to be consistent and organized. I also see it when spot replacement LED fixtures are surrounded by a bunch of HPS.

The gym at my HS still has 400w metal halide highbays and they have a nice variety of colors since they aren't group relamped. Some also have clear lamps while others have coated.

Interesting!


I’ve seen some colour shifted lights that would have a more pinkish hue, and some that were more warm white/almost beige.


Can mercury lamps develop a pinkish hue with age or any other colours depending on the phosphor?

Or are you more likely to see more diverse colour shifting on metal halide?

Colour shifting in mercury lamps is caused by the blackening of the arctube which absorbs some wavelengths. This reduces the amount of UV converted into visible light. The phosphor also degrades over time, decreasing the red light output. And then you've got your greenish MV oclour. 

In metal halide lamps, it's a different phenomenon. Some of the halides in the arctube are chemically pretty active, compared to mercury. These tend to escape the arctube over time. In that case some wavelengths simply disappear instead of being barely absorbed by arctube blackening (though that still happens too). Depending which particular halide calls it quits, it's produce a different colour shift. But I'm not knowledgeable enough when it comes to MH lamp chemistry to know which halide produces which colour LOL. Aside from the obvious mercury's green & blue and sodium's orange, I think scandium produces green light.

Interesting, makes sense.



As for the pink lighting I heard how some of the other chemicals can burn off and then you’re just left with argon, which will give off the pink light. Apparently metal halides can turn pink near EOL.


Not sure if this could happen with MV too. Hmmm 🤨🤔

I remember all the shops of the 1980s which had double ended 70W MH spotlights and some of them turned green or blue as they aged. Same at grocery stores which had white HPS spotlights and the light there was always a mix of different shades of gold. New bulbs lit almost white while the older shifted their colour to gold and the even older ones almost red.

Here in cities the street lights always have been group replaced so there was almost not any colour change of aged lamps visible within a road as they aged altogether the same.

The car wash I like to go to has many colour shifted lowbays. I think they are MV?

Some are pinked out, some very greened out, some bluish, some warm-white/beige, very interesting. Some of them have been spot replaced by LED though

The car wash I like to go to has many colour shifted lowbays. I think they are MV?

Some are pinked out, some very greened out, some bluish, some warm-white/beige, very interesting. Some of them have been spot replaced by LED though

From the way you describe their colors, they sound like MH.

From the way you describe their colors, they sound like MH.

Ah interesting, makes sense I guess due to the possibility of more chemicals in the arc to change.



Makes me wonder if some of those old streetlights where I lived as a kid could have been retrofitted with MH 🤔🤔🤔