Hmmm. Jez Ford has drawn my attention to this article on CNET, which says that the black levels of Panasonic plasma TVs become less black over time. It’s all a bit vague, but it seems to be saying that the TV has a long-term operating profile programmed into it to optimise picture quality according to the changes in the physical characteristics of the plasma cells.
I suppose that if the plasma cells do change in their performance as they are used, then it’s appropriate to optimise the picture for those changes. Presumably the cell changes are due to some kind of generalised burn-in (plasma burn in, in the sense of leaving visible after-images, hasn’t been a problem with Panasonic TVs for some years).
It would be nice if there were some indication of how much brighter the blacks will become over that time.
One thing I always feel a little guilty about with reviews is that all I can really talk about is how well something operates when it is new. For all I know every product (except for the ones I own) burst into flames after six months of use.
I simply can’t think of a way around that.