The first thing on our check list as we started assessing the 50PK990’s pictures was the severe image lag noted with our 50PK790 sample last week. And we were disappointed to find that some image retention is still there, albeit at a markedly less severe level than we noted on the 50PK790.
You only have to leave, say, the Sky News or CBeebies logo on screen for a few seconds before it’s made enough of an impression to still be visible for some time over subsequent images - especially if those subsequent images contain swathes of single colour in the areas where the logos appear. However, it must be said that the ghostly shadows of pictures past are far less overt than they were on the 50PK790 - in fact, they’re generally less prone to appearing at all.
With no usage timer on the screen it’s impossible to say if this image retention improvement with the 50PK990 is just because the sample LG sent us has done many more hours of service than the 50PK790 we had; after all, the sort of image retention problems we’re talking about should diminish the longer you use the screen for. But whether it’s down to usage time or an improved panel design at the 50PK990’s heart, we can only report what we see: and that’s less evidence of ghostly remnants of bright, colourful picture elements lingering over pictures long after they should have gone.
This makes the 50PK990 a more immediately attractive proposition than the 50PK790 we tested - though the fact remains that really we don’t see why any of today’s plasma TVs should suffer any image retention at all, no matter how short-lived the phenomenon might turn out to be.
One other very curious - though possibly related - phenomenon of the 50PK990 manifests itself exclusively, so far as we could tell, when playing Xbox 360 games. What happens is that sometimes bright image elements cause a ‘cast off’ stripe to spread across the screen beyond the boundary of the area that should be illuminated.
The most obvious example of this can be seen in the Xbox Live menus of Call of Duty: Modern Warfare 2, which features a sort of ‘striped’ menu system. If you scroll between the options on these striped lists, you can clearly see a ghostly extension of your currently selected ‘stripe’ spreading for a good three or four inches across the screen beyond the point where the actual menu bar finishes. We double checked this against four other TVs we had lying around, and not one of those produced the same curious ‘streaking’ issue.
The good news here is that we never noticed a similar problem with normal video viewing - even when watching white titles against black backgrounds. And nor did we notice the streaking more than once or twice during normal Xbox gameplay conditions. In fact, our main reason for mentioning it is that it’s just another little pointer towards LG needing to tighten up its plasma image controls a tad for its next plasma generation.