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, which allows for a very realistic image. Of course, none of them surpasses the magical thousand, however, the combination of such results along with unlimited contrast and black effectively boosts the visual outcome. The last of the scenes, featuring a fullscreen sun burst, is indeed less bright than the others, although it still represents a respectable level. It's also worth mentioning the excellent coverage of the DCI-P3 colour palette, which will enable the achievement of exceptionally vivid colours.

The HDR performance of the LG C6 is really very good. LG Display’s new WOLED panel has mainly brought a significant increase in brightness. In our unit we measured around 1500 nits and, importantly, the TV can show similar values in many normal movie scenes as well. That gives HDR real punch. Bright highlights, lamps and sunlight can be genuinely intense, and most HDR movies simply look very impressive. Of course it’s still an OLED, so brightness falls in scenes with a lot of white. The fifth scene from the movie The Meg illustrates this well, where the C6 reached around 600 to 700 nits. That’s still a very good result, but it also shows the new panel hasn’t shed all the limitations typical of OLEDs.

Colours

When it comes to colours, it’s also hard to raise major objections. The C6 covers about 99% of the DCI-P3 gamut and roughly 75% of BT.2020. In practice colours are very saturated and, importantly, stable regardless of the scene. That’s 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 gamut today is mainly offered 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 movie scenes.

The best factory mode implemented in the tested television was "Filmmaker". That was the one we used during all tests. This mode, in terms of colour reproduction, turned out to be quite decent, although other flaws effectively detracted from the enjoyment of the viewing experience. Starting with the most basic one, which is white balance, it was easy to notice that this was marked by a dominance of red, which completely altered the characteristics of the picture. We could see a strong yellowing of the whites and a shift of all colours to warmer tones. The gamma, which is a graph as equally important, if not more so, was quite severely reduced, resulting in a significant drop in contrast, except for the start of the graph, where the television insidiously lost details. That’s all regarding SDR materials. Looking closely at films with a wide dynamic range, we can observe exactly the same phenomenon of white balance yellowing as in films with a standard colour palette. The EOTF curve, which replaces the gamma chart for us, is practically perfect and cannot be faulted.

Right out of the box the LG C6 is quite well set up, especially if you choose the Filmmaker mode. In SDR material the white balance is decent, although as brightness increases there is a slight lack of red. The image becomes a bit cooler, but not enough for it to be very noticeable during normal viewing. More is happening in the brightness characteristic. Gamma is a little low and instead of holding at 2.4, for a large part of the range it sits closer to 2.1–2.2. 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 darkened room.

In HDR the situation is a bit more interesting. The start of the greyscale looks very good, but from about 20–30% brightness the white balance starts to drift increasingly. As brightness rises there is more red and a noticeable lack of blue. In the brightest sections the difference is already significant and also affects the reproduction of some colours. The EOTF curve itself is followed quite well through most of the range. The C6 only tends to slightly brighten the image, which we also saw in our film comparisons. The largest deviation appears around the brightest parts, where the TV starts adapting the signal to the panel's capabilities.

The factory Filmmaker setting in HDR is therefore not perfect, but overall performs well. The biggest area 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 used them to model the picture in line with what the director envisioned. And without modesty, we must admit that we achieved this phenomenally. Both SDR and HDR materials present a level that clearly indicates this is how a film should look. It's worth taking a look at the colour errors on the "ColorChecker" palette, where practically none of them exceed "1", except for two samples.

LG TVs have long responded very well to calibration, and the C6 is no exception. After adjustments we managed to set the white balance practically perfectly, and most colour errors fell below 3, often down to around 2. In practice this means very accurate colour reproduction in both SDR and HDR. An interesting detail only appeared with the HDR brightness response. On a classic EOTF chart everything looks almost perfect and at first glance it would be hard to find fault. Only when we measured the TV’s behaviour using filters based on real film scenes did it become clear that the C6 has a slight tendency to artificially boost image brightness.

It’s not a huge difference and many viewers may even see it as a positive, because HDR looks a bit more striking as a result. From the point of view of fidelity to the source material, however, it’s not ideal — 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 held very closely to the reference picture curve after calibration. The C6 is still very close to the standard, but that subtle brightness 'boost' can indeed be noticed in films and TV series.

Once again, we will take a look at the feature responsible for gentle gradation, but we will also address the one that aims to enhance the quality of lower-quality materials. The default smoothing of tonal transitions, as we could see, was not the worst, but it can be improved further. The function has a slider that allows us to adjust its intensity. We recommend using the former, as it produces very good results and does not blur important details.

Image scaling on 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. While jagged edges of trees can be seen, it is not a major issue when compared to other manufacturers.

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

The maximum refresh rate we can set on the LG G4 is 144 Hz. Naturally, this is only possible when connecting the TV to a very powerful PC. Otherwise, we will operate at a maximum refresh rate of 120 Hz, which is recommended if we primarily want to watch sports or content with a lot of motion dynamics. For those who require high fluidity of the image, the manufacturer has implemented a multi-level 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 in the range of 0 to 10, with each degree affecting the level of smoothing, allowing everyone to find their sweet spot.

The panel of the LG OLED C4 features an average response time of less than 1 ms (which directly results from our measurements), enabling the achievement of an extremely clear image, unattainable for LCD TVs, which can have response times of up to several milliseconds. This is clearly evident in the images from the "UFO Test," which show no trailing blur behind the object.

The LG C6 features a panel with a maximum refresh rate of 165 Hz, which is great news especially for gamers using a powerful PC. For movies, sport and consoles we’ll of course be limited to 120 Hz at most, but even then it’s hard to fault the motion clarity. As you’d expect from an OLED, the panel’s response time is near-instant. Moving objects therefore don’t leave the characteristic smearing you still see on LCD TVs. This is especially noticeable in sport and fast-paced games, where the picture remains very clean even during dynamic movement.

For movies and TV, LG has also included a motion smoothing system called TruMotion. In the user settings you’ll find two separate sliders. De-Judder is primarily for low-frame-rate material, namely movies and TV series at 24 fps. You can use it to slightly reduce the characteristic judder or increase it if you prefer a much smoother picture. De-Blur, on the other hand, is useful for higher-frame-rate content, mainly sports broadcasts and 50/60 fps TV.

We can now say that LG C4, like practically every OLED television from the manufacturer, is exceptionally good in terms of cooperation with consoles and PCs. Thanks to the implementation of four full-bandwidth HDMI 2.1 ports at 48 Gbps, the manufacturer has embedded all the features that enhance gaming comfort, including simultaneous support for FreeSync and G-Sync technologies. With such a tandem, players with graphics cards from AMD or nVidia can safely choose C4. However, what should please gamers demanding the highest possible quality the most is the simultaneous implementation of HDR Dolby Vision and HGIG mode. The former is particularly important as it operates with extremely low input lag in all settings.

A standard feature in televisions from the Korean manufacturer is also the implementation of GameBar, allowing for quick adjustments of settings "on the fly," without the need to exit the game. It also allows for image adjustments for people with visual impairments, which is an incredibly nice touch. Another important piece of information is that when VRR technology is enabled, we won’t experience a drop in contrast. This is, of course, due to the design of the panel and the absence of conventional backlighting. It is, however, 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 the manufacturer's OLEDs equipped with high-refresh-rate panels and HDMI 2.1 connections, creates a harmonious whole with consoles. In practice, it is a complete television, and if we expect the highest possible efficiency in gaming, C4 will be an ideal choice.

LG has long focused heavily on gamers, and the C6 essentially lacks nothing important. The TV supports 4K at 120 Hz from consoles, and when connected to a PC it can even run at 165 Hz. On top of that there’s VRR from 40 to 165 Hz, ALLM and a properly functioning HGiG. Another big plus is support for Dolby Vision in games, so the Xbox Series X can use that format without giving up game mode. The package is rounded out by the Game Bar, which lets you quickly check key signal parameters and change settings without leaving your game. In terms of features alone, the C6 is one of those TVs it’s really hard to fault. Whether you play on PlayStation, Xbox or PC, practically everything you could expect from a modern gaming TV is available here.