LG Infinia 50PK790 50in Plasma TV - LG Infinia 50PK790

John Archer

By John Archer



Our Score:


And now to reveal that aggravating flaw mentioned right at the start of this review: image retention.

Basically, throughout the few days that I had the 50PK790, my use of it was constantly blighted by extremely distracting residual ‘echoes’ of bright, colourful image elements hanging around over subsequent images - sometimes for as much as an hour at a time.

And before you ask, no, I’m not talking about a phenomenon that only happens if I leave the Sky News logo playing uninterrupted for a good few hours. Even bright image content that’s only been on screen for a few seconds can still be clearly, annoyingly visible on the next few frames, especially if those subsequent frames are predominantly dark.

The only time I did experimentally leave the Sky News logo running on the screen for any significant amount of time - a couple of hours, I guess - I could clearly see its ghostly outline hanging over anything else I watched afterwards for at least an hour, possibly more.

Of course, plasma TVs used to suffer quite routinely with image retention, and were renowned for falling prey to permanent screen burn if you really pushed your luck. I also know that plasma TVs are more prone to image retention during the first 100 hours or so of their life, so I’d expect - though can’t guarantee - that the problem will reduce as the 50PK790 gets older.

But even so, there’s simply no getting round the fact that the retention problems on the 50PK790 are troubling even by old plasma standards, and shouldn’t exist to anywhere near this extent on a 2010 plasma model. And before you ask, I was so concerned about the problem that I ordered a second model from LG’s new range, the step-up 50PK990, and found that this suffered with the same problem, albeit to a lesser extent.

This really is a hugely frustrating issue that for me - as someone who hates anything that distracts me from what I’m supposed to be engrossed in watching - spoils what might otherwise have been a potential 'TrustedReviews Recommended' TV. Sigh.

For the record, the audio the 50PK790 produces to accompany its nearly-great pictures is above average. There’s not as much bass as I’d like, but this is a common flat TV failing, and at least the 50PK790 does better than many rivals at presenting an open, detailed, distortion-free mid-range that seldom feels underpowered.


If you’re a patient sort willing to put up with the 50PK790’s image retention problem for a good many hours after you first get the TV, then presumably - hopefully?! - your patience will be rewarded with a really good all-round picture performance once the retention problem has gone.

But why should you have to be patient with LG’s plasma TVs when similarly accomplished TVs from other brands work fine straight out of the box?


May 1, 2010, 4:55 am

Shame that as I was expecting LG to start solving IR in 2010 ... probably it will only be a problem in one or two sets perhaps??

Also not sure how you go about getting to that OVERALL score:






and OVERALL which I guess most people will use to purchase or not 7/10.

How does that work exactly??


May 2, 2010, 4:48 pm

I must agree - the overall score is 8.2/10

It is illogical to give high scores when the overall score is not reflective.

'Tis a shame indeed.


May 2, 2010, 6:48 pm

Quite simply, our overall scores are not a summation of the other scores, though more often than not they do correlate. Admitedly this is an extreme example but there is still logic to it: image quality is the most important aspect of a TV so the overall score is weighted to reflect this. Another example is if an iPod dock looks great, is easy to use, is competitively priced, but sounds rubbish, it's going to have a poor overall score.


May 2, 2010, 10:11 pm

Ah that it explains it a bit better ...

But I am guessing if it was not for the Image Retention issues on this particular TV (have seen other LG 2010 reviews and IR has not been a problem) it would Score a 9 on Image Quality and the same in the Overall scheme of things.

Does that sound about right??


May 3, 2010, 10:39 pm

Ed, with all due respect, I disagree with your usage of the word overall. Is it not supposed to reflect all factors, not just the ones you believe are the most important?

In your iPod dock example, if all other scores were say, less than 5/10, but the sound reproduction scored a 10/10, you would give it 9/10 or higher?

You could of course not give any scoring at all for the features, design etc - but just give an overall score and let the reviewer pass or fail the various factors in the written review.

This would make more sense as the reviewers comments are generally well written at TR and typically consider factors that other sites skim over.

I appreciate it is difficult when considering what final mark to give something, and it must be even harder when a 9/10 today could be a 8/10 tomorrow as new technologies and models enter the market, skewing the figures somewhat, however I feel this is an area worth consideration.


May 4, 2010, 1:39 pm

@davidcroft: That does indeed sound about right.

@Mitch: You're kind of missing the point. I'm not talking about dismissing other factors entirely, just giving them more emphasis. Also, this isn't subjective weighting here, this is cold hard consideration of the fact that the image quality of a TV is the most important element. There's just no two ways around that.

As for a single score, let's just say we're thinking about it.


May 5, 2010, 2:45 am

I am really worried now i have a LG pk590 coming any day now,cnet have tested it and no mention of ir,maybe because its a different range from the infinia, hopefully it will be ok or its going straight back.

Richard 27

May 6, 2010, 12:20 am

I was thinking about getting one too but after reading this I'm not too sure...so what would be a better alternative, for a 50" that offers all of the 790s spec costing approx 1k but without the IR prob? thanks


June 14, 2010, 9:08 pm


yeah I was thinking about getting a LG 50PK590, will that share the same IR problems as both the 790 and the 990, or will it not necesarily be so bad, considering it is not part of the "infinia" series.

@paul how did you find it? did you end up sending it back, or did it turn out ok?

I have heard very good things about the 550 and no one has mentioned anything about serious image retention problems.

Thanks in advance, Cook.


June 22, 2010, 4:52 am

cookie,sorry took so long to answer,i love the lg pk590,cant say ive seen any image retention,great hd picture sd pretty good depends what channel your watching ,quite slim with a slim frame,played cod 4 on it fantastic colours and no motion blur,

of course there are better tvs but for around £712 i cant see a better buy at the moment.

Amazon are selling it £718 and rgb direct £712 both free delivery.


July 5, 2010, 10:14 pm

Thanks a lot paul; probably gonna pick a pk590 up fairly soon then.

It seems like a much better deal than the 790 or 990, i don't know why TR don't review the "pick of the bunch".

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