I've noticed something quite odd! There is a Gamma 6 (on Stanton concrete column) that I regularly pass when it is dark, and it always seems to be on pink! I have never seen anything like it around here because if anything dodgy happens with lamps, it tends to be one end pink, and one end orange... Or a black middle to the lamp.
It was always a late switcher, but the two part cell failed last year, meaning that it spent ages dayburning, then I assume the lamp blew as it was unlit for quite a while. It did get the two-part cell sorted, and it switches on OK, it just doesn't seem to warm up to anything more than pink! It's a bit bizarre considering it is a fairly new lamp [I think but am not certain]
I have read that SOX lamps are supposed to burn red when they are near the end of their life, but the lamps around here, like I said, don't seem to burn fully red, and seem to turn orange at least a little bit. Does anyone know what the problem could be?
It is located in a carpark area with an alleyway leading to it, and it looks very odd with the reflection from the water on the pavement. Another interesting point is that the Stanton column isn't set too deep into the ground, and you can see the curve at the bottom of the column above ground level. But of course this isn't anything to do with the lamp.
I'll try to get pictures on Tuesday.If the lamp is old there may not be a strong enough neon discharge to produce the required heat to vapourise the sodium. Also if there is a vacuum leak in the outer envelope enough heat will escape with the same effect. I have a lamp like that, never gets yellow, unless I give it a kick start in the oven!