TCL C9K vs LG OLED C6 (WOLED)

As we mentioned regarding black levels and contrast – the C9K can make a huge impression in synthetic tests. Our measurements showed that on a screen 10% filled with white, the television can achieve... 4000 nits of brightness! It sounds out of this world, but – and here's where the pattern unfortunately repeats – the numbers say one thing, and the practical experience says another. In real movie scenes, the situation looks different. In the best-case scenario, when light effects occupy a large part of the image and the local dimming algorithm doesn't have to ponder too much about what to do with thousands of zones, the effect is really quite good. At that point, the C9K can hit around 1500 nits, which delivers a pleasant, intense burst and can indeed leave a positive impression.

The problem arises with smaller elements – such as stars in the sky, the moon, or individual reflections. That's when the proverbial cat comes out of the bag: the algorithms are not yet refined, and brightness drops to as low as 400–500 nits. That's a huge difference from the potential 4000 nits we saw in lab tests. Why does this happen? Most likely, the television is trying to protect the black levels in this way and minimize the halo effect around bright objects. Unfortunately, this comes at the expense of detail – some details simply vanish, and the scene loses its nature.

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.

For colour tests, we once again reached for the Filmmaker mode – a new feature in TCL televisions for 2025. While the direction is a step in the right way, the execution leaves a lot to be desired. The white balance in SDR content turned out to be too warm – there was an excess of red. On the other hand, in HDR, it swung in the opposite direction: the image became excessively blue. The Colour Checker test revealed quite a few colour inaccuracies that were noticeable to the naked eye. An even bigger problem turned out to be what we mentioned above – brightness management. Regardless of whether we were watching SDR or HDR content, the image tended to wash out the entire scene, giving it an unnatural, almost grotesque character. Therefore, it’s hard to call this a "director's mode" – because no director has ever seen such an image.

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.

After calibration, we finally managed to tame the white balance – and it immediately translated into a more natural image. Colours finally started to look as they should, and the overall presentation was incomparably better than on the factory settings. In other words – it’s worth taking a moment to improve this, as the gain is really significant. The gamma responsible for brightness management also managed to be brought into order in SDR content, and the effect was more than satisfactory. Unfortunately, when we turned on HDR materials, the situation quickly became complicated. No matter how we set the local dimming, the television had a tendency to do what it liked with the image – either it overexposed everything or darkened the darkest parts too much. Just like we saw in the scene from the movie Billy Lynn. Colour-wise, the improvement after calibration makes a great impression, but brightness management in HDR remains the Achilles' heel of the C9K and presents a certain technological limitation.

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.

Digital image processing on the TCL C9K is rather average. The smooth tone transition feature seems to be present, but activating it practically changes nothing – colour bands are still visible, and it can unintentionally highlight elements we’d rather keep hidden, such as object textures. Fortunately, it doesn’t remove film grain, but that’s poor consolation given that the effects are still meagre. It’s therefore hard to recommend using this option.

On the other hand, image scaling presents itself much better. Lower quality materials look quite decent – characters and backgrounds are rendered clearly, although of course, with sources like 576p, the laws of physics cannot be fooled. Occasionally, there’s characteristic edge distortion of objects, but that’s the fault of the source itself, not the algorithm. A plus for not having issues with overscan – the image isn't artificially cropped or enlarged.

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.

Similar to the C8K, the C9K is also a really fast TV – both figuratively and literally. It features a 4K panel with a refresh rate of 144 Hz, and at lower resolutions, the panel can even ramp up to 288 Hz. Such speed translates into practice – while watching sports or playing games, the image looks very smooth and clear. Additionally, in movies, we get an extra motion smoother called Motion Clarity, which allows you to adjust the smoothness to your own preferences – from cinematic "judder" to almost theatrical smoothness.

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.

From a gaming perspective, the TCL C9K is a complete tool. It features two (out of four) full bandwidth 48 Gbps HDMI 2.1 ports, so all the key technologies work: VRR (Variable Refresh Rate) and ALLM (Auto Low Latency Mode). Additionally, the manufacturer has included a really intuitive Game Bar that allows you to quickly check the most important parameters and adjust settings without fumbling through menus. Also, TCL's policy is a plus – the TV isn’t afraid of any HDR formats, even in game mode. Whether it's HGiG or Dolby Vision for the Xbox Series S/X console – everything works as it should, giving the player plenty of freedom.

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.