While the screen looks extremely bright and punchy at the lightest, most colourful end of the visual spectrum, it struggles to deliver a convincing black colour.
This takes place on two levels; the general tone of dark scenes is rather grey, leaving you squinting through a gentle fog in search of shadow details and the same problem finds dark scenes looking much less convincing than bright ones.
Worse is the appearance in each of the 47LX6900's corners of some marked backlight inconsistency. This is invisible during bright scenes, to be fair, but it's impossible to miss/ignore during very dark scenes.
Black levels improve in some ways if you activate the local dimming feature, but the aforementioned downsides to using this feature outweigh any benefit.
The other serious problem with the 47LX6900 is 3D crosstalk. Whenever you watch any three-dimensional material – regardless of whether it's Blu-ray, a console game or Sky's 3D channel – the performance is hindered by the clear and consistent appearance of double ghosting around some objects and edges, especially those in the mid to far distance.
As well as reducing the sharpness of 3D pictures, the crosstalk noise makes the overall experience rather arduous.
No 3D TVs has completely avoided crosstalk so far, but the extent to which it mars the 47LX6900 is much higher than it is with some rival screens, particularly plasmas.
Continuing the negative theme, the 47LX6900's colours don't impress as much as they have with a number of other recent LG TVs. They are undoubtedly dynamic and rich but aren't as subtle as they ought to be, resulting in slightly artificial skin tones as the TV fails to delineate small, but crucial tonal differences.
One last problem is that while the motion processing manages to keep blur on a tight leash, it also generates a few unwanted processing side effects on all bar the very lowest settings. The same can be said, of course, of many motion compensation engines, but the 47LX6900 seems less adaptive than the best rival systems.
Pictures are, however, impressively vibrant and dynamic. These innate, aggressive qualities serve the set particularly well when showing 3D, since they fight very effectively against the way 3D images lose brightness and saturation when you don active shutter 3D glasses. Certainly, the 47LX6900's 3D pictures look much more dynamic and punchy than those of Panasonic's otherwise excellent 3D plasma TVs.
The 47LX6900 also really seems to enjoy highlighting all the detail that defines high-definition material, delivering sharpness and texturing galore with Blu-rays or HD material from its Freeview HD tuner.
It's a solid standard-definition upscaler as well, delivering good sharpness and retaining convincing colours, but falling short of the very best standard-def full HD performers by tending to slightly emphasise source noise.
The 47LX6900's combination of rich colours, good detailing and high brightness can result in some really pretty blistering 2D pictures at times. It's just a pity that these times don't include any dark scenes.