One month later...... just a trace of some aging. A lot of PL lamps brown up rather quickly. This is running 24/7 using 30 days as time it has 720 hours on it.
Powell
You see this browning when the lamp is OFF, or even when ON (lower lumen otput...)
I have experience, then even if they are nearly black, the light output is normal (side-to-side compare with new one). I expect it is the condensed mercury, what evaporate at lamp warmup...