Quite an old 3500K white 8W fluorescent tube which has been coated with a really vivid pink laquer. It's unclear whether the lamp left the factory like this, whether the finish was applied by a distributor, or whether the end user applied it for a reason such as using the light for theatrical effects - which it could have provided quite an effective low intensity colour wash.
The heat of the tube as you can see has resulted in the finish shrinking and cracking quite a bit, resulting in quite an interesting crackled finish. While a bit of an issue if the tube is directly viewed - if this were to be used indirectly to provide background lighting or similar effects that's really not a problem unless a very large amount of it flakes off, to the extent that it could significantly reduce the saturation of the colour.
The colour is actually much as you see it below - really quite a saturated "hot pink" colour when lit. The tube takes on more of a magenta hue when viewed unlit though...a colour which plays havoc with any digital camera's colour balance and doesn't get treated too kindly by JPEG compression...so the images maybe aren't quite as clean looking as they might normally be.
The spectral plot did come out quite well though - the main notable function that this coating serves you can quite clearly see is that it completely suppresses the normally very visible green mercury line and significantly attenuates the somewhat dimmer blue one.
