LG OLED C4 vs LG OLED C6 (WOLED)

The results of HDR materials are definitely among the better ones. Practically every film significantly exceeds the 700 nits barrier, allowing for a very realistic image. Of course, none of them surpasses the magical thousand, yet the combination of such results and unlimited contrast and black effectively boosts the outcome optically. The last of the scenes, featuring a full-screen burst of sunlight, is actually less bright than the others, although it still represents a commendable level. It is also worth mentioning the excellent coverage of the DCI-P3 colour palette, which will allow for achieving extremely vivid colours.

The HDR performance of the LG C6 is really very good. LG Display's new WOLED panel has primarily brought a considerable increase in brightness. In our unit we measured around 1,500 nits and, importantly, the TV can deliver similar values in many typical film scenes. That gives the HDR the necessary impact. Bright highlights, lamps and sunlight can be really intense, and most HDR films simply look very impressive. Of course it's still an OLED, so brightness falls in scenes with a lot of white. This is well illustrated by the fifth scene in the film The Meg, where the C6 reached around 600 to 700 nits. That's still a very good result, but it also shows that the new panel hasn't shed all the limitations typical of OLEDs.

Colours

When it comes to colours, there is also little to complain about. The C6 covers about 99% of the DCI-P3 gamut and roughly 75% of BT.2020. In practice the colours are very saturated and, importantly, stable across different scenes. This is worth emphasising, because not every TV behaves the same in this respect. In some RGB Mini LED models colour saturation can depend more strongly on image brightness. A wider colour palette is nowadays offered mainly by QD-OLED TVs and new SQD models with a new generation of quantum dots. However, the C6 still performs very strongly here and is able to produce suitably saturated colours in most film scenes.

The best factory mode implemented in the tested television was "Filmmaker". It was this mode that we used during all tests. This mode proved to be quite good in terms of colour reproduction; however, other shortcomings effectively detracted from the enjoyment of viewing. Starting with the most basic aspect, the white balance, it was easy to notice that it was marked by a dominance of red, which overall changed the characteristics of the image. We could thus see a strong yellowing of the whites and a shift of all colours towards warmer shades. The gamma, which is a curve just as important, if not more so, was quite significantly lowered, resulting in a considerable drop in contrast, except at the beginning of the graph, where the television insidiously lost details. That’s all regarding SDR materials. Taking a closer look at films with a wide dynamic range, we can observe exactly the same phenomenon of yellowing of the white balance as in films with a standard colour palette. The EOTF curve, which replaces our gamma curve, is practically perfect and cannot be faulted.

Right out of the box the LG C6 is pretty well set up, especially if you choose Filmmaker mode. In SDR material the white balance is decent, although as brightness increases it starts to lack a bit of red. The picture becomes a little cooler as a result, but it’s not such a big difference that it stands out during normal viewing. More happens in the brightness response itself. Gamma is a bit low and instead of holding at 2.4 it sits closer to 2.1–2.2 over much of the range. In practice the C6 slightly brightens midtones. Shadows are therefore more readable, but the image loses some depth compared with how it should look in a dark room. In HDR the situation is a bit more interesting. The start of the grayscale looks very good, but from about 20–30% brightness the white balance starts to drift more and more. As brightness rises there’s more red and a noticeable lack of blue. In the brightest highlights the difference is already significant and also affects reproduction of some colors. The EOTF curve itself is handled fairly well over most of the range. The C6 only has a tendency to slightly brighten the image, which we also saw during our film comparisons. The largest deviation appears around the brightest highlights, where the TV begins to adapt the signal to the panel’s capabilities. So the out-of-the-box Filmmaker mode in HDR isn’t perfect, but overall it performs well. The biggest room for improvement is the white balance, especially at high brightness.

As we mentioned earlier, LG televisions are equipped with advanced tools for carrying out the calibration process. We therefore used them to model the image in the way that the director intended. And without modesty, we must admit that we achieved this phenomenally. Both SDR and HDR materials present a level that clearly indicates that this is how a film should look. It is worth looking at the colour errors on the "ColorChecker" palette here, where practically none of them exceeds "1", apart from two samples.

LG TVs have been very receptive to calibration for years and the C6 is no exception. After adjustment the white balance was set almost perfectly, and most colour errors dropped to values below 3, often even around 2. In practice this means very accurate colour reproduction, both in SDR and HDR. An interesting quirk only appeared with the luminance response in HDR. On a standard EOTF chart everything looks almost ideal and at first glance it would be hard to criticise. Only when we measured the TV's behaviour with filters based on actual film scenes did it become clear that the C6 has a slight tendency to artificially boost image brightness.

This is not a huge difference and many people may even view it positively, because HDR consequently looks a little more striking. From the perspective of fidelity to the source material this is not ideal, however, as some scenes are simply a touch brighter than the filmmaker intended. Interestingly, this is rather unusual for LG. In previous generations the brand's TVs typically stuck very closely to the reference picture characteristic after calibration. With the C6 we are still very close to the standard, but this subtle brightness boost is indeed noticeable in films and TV series.

Once again, we will take a look at the function responsible for smooth gradation, but we will also address the one that aims to improve the quality of lower-quality materials. The default smoothing of tonal transitions, as we have seen, was not the worst, but it can still be improved. The function has a slider, which allows us to adjust its strength. We recommend using the first one, as it yields very good results and does not blur important details.

Image scaling in LG C4 is quite good; however, it cannot be said to be without flaws. The image is slightly sharper by default, although not in a very noticeable way. Admittedly, there are jagged edges on the trees, but this is not a major issue compared to other manufacturers.

Here the LG C6 has taken a real step forward. The TV uses the same processor found in the flagship G6, and in terms of image processing the two models are very similar. That's a considerable plus, because in this area LG's processor this year performs excellently. The "Smooth Gradation" function in particular works very well. With heavily compressed material it can effectively hide ugly banding and artefacts that often appear, for example, in lower-quality streaming. It's best to leave it set to "Low". That way the improvement is clear and the TV does not yet start blurring fine details. Higher settings smooth the image more aggressively but can already remove some of the natural texture of objects on the screen. Upscaling itself also performs very well. Lower-resolution content is sharpened correctly, edges look clean, and the processor quite effectively reconstructs fine details. In this respect the C6 is already very close to LG's best TVs and the differences compared with the G6 are small.

The maximum refresh rate that we can set on the LG G4 is 144 Hz. Naturally, this is only possible when connecting the television to a very powerful PC. In other cases, we will be operating at a maximum refresh rate of 120 Hz, which is recommended if we primarily want to watch sport or content with a lot of motion dynamics. For those requiring high fluidity of the image, the manufacturer has implemented a multi-step motion smoother called "TrueMotion". It has been divided into two separate sliders that adjust the sharpness of moving images (De-Blur) and judder (De-Judder). Both sliders can be set within a range from 0 to 10, with each degree affecting the degree of smoothing, allowing everyone to find their golden mean.

The LG OLED C4 panel features an average response time of less than 1 ms (which directly results from our measurements), allowing for an incredibly clear image that is unattainable for LCD televisions, whose response times can be as high as several milliseconds. This is clearly visible in the pictures from the "UFO Test," showing no trailing blur behind the object.

LG C6 received a panel with a maximum refresh rate of 165 Hz, which is great news above all for gamers using a powerful PC. In films, sport or on consoles we will of course make use of up to 120 Hz, but even then it is hard to fault the motion clarity. As befits an OLED, the panel's response time is almost instantaneous. Moving objects therefore do not leave the characteristic smearing or trails that we can still see on LCD televisions. This is especially noticeable in sport and fast-paced games, where the picture remains very clean even during dynamic movement.

For films and television LG has also prepared the TruMotion motion smoothing system. In the user settings you will find two separate sliders. De-Judder primarily addresses low frame-rate content, that is mainly films and TV series at 24 fps. You can use it to slightly reduce the characteristic judder or set a higher value if you want a very smooth image. De-Blur is useful for higher frame-rate material, chiefly sports broadcasts and 50/60 fps television.

We can already say that LG C4, like practically every OLED television from the manufacturer, is exceptionally good in terms of compatibility with consoles and PCs. Thanks to the implementation of four full bandwidth HDMI 2.1 ports at 48 Gbps, the manufacturer has included all features that enhance the gaming experience, among which we find simultaneous support for FreeSync and G-Sync technology. With such a tandem, gamers with a graphics card from AMD or Nvidia can confidently opt for C4. However, what should delight the players requiring the highest possible quality the most is the simultaneous implementation of HDR Dolby Vision and HGIG mode. The first is particularly important as it works with extremely low input lag in all settings.

A standard in the Korean manufacturer's televisions is also the implementation of GameBar, allowing for quick adjustments of settings "on the fly" without the need to exit the game. It also enables image adjustments for visually impaired individuals, which is a very nice touch. Another important piece of information is that when VRR technology is enabled, we will not experience a drop in contrast. This is, of course, due to the panel's design and the absence of conventional backlighting. However, it is normal for shades of grey to flicker slightly, although this is a characteristic feature of this function regardless of the manufacturer and television.

In summary: LG C4, just like all of the manufacturer's OLEDs equipped with high refresh rate panels and HDMI 2.1 ports, creates a harmonious whole with consoles. In practice, it is a complete television, and if we expect the highest possible performance in gaming, C4 will be an ideal choice.

LG has long focused heavily on gamers, and the C6 really lacks nothing important. The TV supports 4K at 120 Hz from consoles, and when connected to a PC it can run at up to 165 Hz. There is also VRR from 40 to 165 Hz, ALLM and a properly working HGiG. A big plus is support for Dolby Vision in games, so the Xbox Series X can use that format without giving up Game Mode. It's rounded off by a Game Bar, from which you can quickly check key signal parameters and change settings without leaving the game. In terms of features, the C6 is therefore one of those TVs that is really hard to fault. Whether you're gaming on a PlayStation, an Xbox or a PC, practically everything you could expect from a modern gaming TV is available here.