TCL C9K vs LG OLED C6 (WOLED)

As we mentioned with black and contrast – the C9K makes a huge impression in synthetic tests. Our measurements showed that on a screen 10% filled with white, the television is capable of squeezing out... 4000 nits of brightness! It sounds cosmic, but – and here unfortunately the pattern repeats – the numbers say one thing, and practice another. In real film scenes, the situation looks different. In the best case, when the light effects occupy a large part of the image and the local dimming algorithm doesn't have to think too hard about what to do with thousands of zones – the result is really quite good. At that point, the C9K can reach about 1500 nits, which provides a pleasant, intense flash and can indeed make a positive impression.

The problem begins 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 even to 400–500 nits. This is a huge difference compared to the potential of 4000 nits that we saw in laboratory tests. Why does this happen? Most likely, the television tries to protect the black and minimise the halo effect around bright objects. Unfortunately, this comes at the cost of details – some of the intricate details simply disappear, and the scene loses its nature.

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.

For colour tests, we once again reached for the Filmmaker mode – a new feature in TCL televisions for 2025. And although the direction itself is a step in the right direction, the execution leaves much to be desired. The white balance in SDR content turned out to be too warm – there was an excess of red. Conversely, 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 – managing brightness. Regardless of whether we were watching SDR or HDR content, the image had a tendency to blow out the entire scene, giving it an unnatural, almost grotesque character. Therefore, it is hard to call this a 'director’s mode' – because the director surely has never seen such an image.

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.

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 with 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 managing brightness was also brought under control in SDR content, and the effect was more than satisfactory. Unfortunately, when we switched on the HDR material, the situation quickly became complicated. No matter how we set the local dimming, the television had a tendency to do what it pleased with the image – either overexposing the whole picture or dimming the darkest parts too much. Just like we saw in the scene from the film Billy Lynn. Colour-wise, the improvement after calibration makes a great impression, but managing brightness in HDR remains the Achilles' heel of the C9K and constitutes a technological limitation.

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.

The digital image processing in TCL C9K is rather mediocre. The tone transition smoothing feature is supposedly present, but activating it hardly makes any difference – colour banding is still visible, and it can inadvertently highlight elements we would prefer to hide, such as textures of objects. Fortunately, it does not remove film grain, but that's scant consolation considering the effects are still poor. Thus, it's hard to recommend using this option.

On the other hand, image scaling performs significantly better. Lower quality materials look quite decent – characters and backgrounds are represented clearly, although of course, with sources like 576p, the limitations of the physics cannot be disguised. Sometimes, there's characteristic aliasing of objects, but that's due to the source itself, not the algorithm. A plus for the fact that there are no overscan issues – the image is neither artificially cropped nor enlarged.

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.

Similar to the C8K, the C9K is also a really fast television – both figuratively and literally. On board, we have 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 picture looks very smooth and clear. Additionally, in films, we get an extra motion smoothing feature called Motion Clarity, which allows you to adjust the smoothness to your own preferences – from the cinematic "stuttering" of frames to nearly theatrical smoothness.

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.

For gaming, the TCL C9K is a complete tool. Here we have two (out of four) HDMI 2.1 ports with full bandwidth of 48 Gbps, 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, which allows you to quickly check the most important parameters and adjust settings without rummaging through the menu. Also worth noting is TCL's policy – the television does not shy away from 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 a wide range of freedom.

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.