I just replaced a Philips 120 cm 827 with an Osram, as the Philips was flickering badly, and replacing the ballast hadn't helped. Couldn't get a Philips near where I lived, and I doubt if anyone does 120 cm fluorescent tubes mail-order at any reasonable price, if at all.
I noticed that the spectrum emitted by the Osram was significantly different to the tube next to it - the Osram being of a more greenish cast (or the adjacent fitting more pinkish). (The tubes are adjacent to a white tiled splashback). I swore gently under my breath. So off I go to another room to extract what I thought was an existing Philips tube to swap, so I could get the same spectrum in fittings next to each other. This was working on the assumption that the phosphor mix between the Philips and the Osram 'Warn White' was sufficiently different to show up as different emission spectra.
Now here's the odd thing. The older tube had a spectrum that matched the older fitting in the kitchen - which was good news, but wasn't a Philips - but in fact another Osram. The older fitting has a Philips tube.
So, I'm lucky to get a colour match good enough for my eyes, but now intrigued: do fluorescent tube emission spectra change subtly over time as they age? It's the only explanation that makes sense to me.
It is also incredibly irritating. It looks like that if I have multiple fluorescent fixtures in a room, changing any one of the tubes will stand out like a sore thumb until it is 'run in'. Yet another irritation to deal with when using 'energy efficient' lighting.
Grump over.
Sid