TCL C9K vs LG OLED C6 (WOLED)

As we mentioned with black 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 is capable of squeezing out… 4000 nits of brightness! It sounds astronomical, but – and here, unfortunately, the pattern repeats – the numbers say one thing, and practice says another. In real movie scenes, the situation looks different. At best, when the light effects occupy a large part of the image and the local dimming algorithm does not have to think too hard about what to do with thousands of zones – the effect is really good. At that point, the C9K can reach around 1500 nits, which provides a pleasant, intense flash and can indeed make a positive impression.

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

The HDR effect on the LG C6 is really very good. LG Display's new WOLED panel primarily brought a significant increase in brightness. In our unit we measured around 1,500 nits and, importantly, the TV can show similar values in many normal movie scenes. That gives HDR the proper impact. Bright highlights, lamps, or sunlight can be really strong, and most HDR movies simply look very impressive. Of course it's still an OLED, so brightness drops in scenes with a lot of white. The fifth scene of The Meg illustrates this well, where the C6 reached about 600-700 nits. That's still a very good result, but it also shows the new panel hasn't removed all the limitations typical of OLEDs.

Colors

When it comes to color, 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 colors are very saturated and, importantly, stable regardless of the scene. That's worth emphasizing, because not every TV behaves the same in this respect. In some RGB Mini LED models color saturation can depend more strongly on image brightness. Today a wider color gamut 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 generate appropriately saturated colors in most movie scenes.

For color tests, as always, we reached for the Filmmaker mode – a new feature in TCL TVs for 2025. And while 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. On the other hand, in HDR, it went in the opposite direction: the image became excessively blue. The Colour Checker test revealed quite a few color errors 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 blow out the entire scene, giving it an unnatural, even grotesque character. It's hard to call this a "director-created" mode – because the director has certainly 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. Colors finally started to look the way they should, and the overall presentation was incomparably better than in the factory settings. In other words – it’s worth taking a moment to improve this, as the gain is truly significant. The gamma responsible for managing brightness was also brought into order in SDR content, and the effect was more than satisfying. 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 dimmed the darkest parts too much. Exactly as we saw in the scene from the movie Billy Lynn. So, the color improvement after calibration makes a great impression, but brightness management in HDR remains the Achilles' heel of C9K and presents a certain 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 color errors dropped to values below 3, often even around 2. In practice this means very accurate color reproduction in both SDR and HDR. An interesting detail appeared only with the HDR brightness characteristic. On a classic EOTF chart everything looks nearly ideal, and at first glance it would be hard to find fault. Only when we measured the TV’s behavior using filters based on actual movie 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 people may even see it as a positive, because HDR looks a bit more impressive this way. From the standpoint of fidelity to the source material this isn’t ideal — some scenes are simply a touch brighter than the filmmaker intended. Interestingly, this is somewhat unusual for LG. In previous generations, the brand’s TVs typically stuck very closely to the reference tone curve after calibration. With the C6 we’re still very close to the standard, but that subtle boost in brightness is indeed noticeable in films and series.

Digital image processing in TCL C9K is quite mediocre. The tonal smoothing feature seems to be present, but turning it on practically changes nothing – color bands are still visible, and it can unintentionally highlight elements we would prefer to hide, such as textures of objects. Fortunately, it doesn’t remove film grain, but that’s small comfort since the effects are still poor. Therefore, it's hard to recommend using this option.

On the other hand, image scaling performs much better. Lower quality materials look quite decent – characters and backgrounds are presented clearly, although, of course, with sources at 576p, physics cannot be fooled. Sometimes, characteristic aliasing on objects appears, but that’s the fault of the source itself, not the algorithm. A plus for not having issues with overscan – the image is not artificially cropped or enlarged.

The LG C6 has taken a really big step forward here. 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 big plus, because in this area LG’s processor this year performs excellently. The "Smooth Gradation" feature works especially well. With heavily compressed material it can effectively hide ugly tonal transitions and artifacts that often appear, for example, in lower-quality streaming. It’s best to leave it set to "Low." Then the improvement is clear, and the TV doesn’t yet start blurring fine details. Higher levels smooth the image more, but can already remove some of the natural texture of objects on the screen. The upscaling itself also performs very well. Lower-resolution content is sharpened properly, edges look clean, and the processor quite effectively rebuilds fine details. In this regard the C6 is already very close to LG’s best TVs, and the differences compared with the G6 are small.

Like the C8K, the C9K is also a really fast television – both figuratively and literally. It features a 4K panel with a refresh rate of 144 Hz, and at lower resolutions, the display can even ramp up to 288 Hz. This speed translates into practice – when watching sports or playing games, the image looks very smooth and clear. Additionally, in films, we get an extra motion smoother called Motion Clarity, which allows us to adjust the fluidity to our own preferences – from the cinematic "judder" frame 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, sports, or consoles we'll of course use up to 120 Hz, but even then it's hard to fault the motion clarity. As you'd expect from an OLED, the panel's response time is almost instantaneous. Moving objects therefore don't leave the characteristic smears you still see on LCD TVs. This is particularly noticeable in sports and fast-paced games, where the picture remains very clean even during dynamic motion.

For movies and TV, LG also provides the TruMotion motion-smoothing system. In the user settings you'll find two separate sliders. De-Judder is mainly for low-frame-rate content, that is primarily 24 fps films and series. It can slightly reduce the characteristic judder, or be set higher if you want a much smoother image. De-Blur is useful for higher-frame-rate material, mainly 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 key technologies work: VRR (variable refresh rate) and ALLM (automatic low latency mode). Additionally, the manufacturer added a really intuitive Game Bar, which allows you to quickly preview the most important parameters and adjust settings without digging through the menu. Also, TCL's policy is a plus – the TV is not 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 wide freedom.

LG has focused heavily on gamers for years, 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 up to 165 Hz. It also offers VRR from 40 to 165 Hz, ALLM, and properly working HGiG. A big plus is Dolby Vision support for games, so the Xbox Series X can use that format without sacrificing game mode. The package is rounded out by a Game Bar that lets you quickly check key signal parameters and change settings without leaving the game. In terms of features, the C6 is one of those TVs that’s really hard to find fault with. Whether you play on PlayStation, Xbox, or PC, practically everything you could expect from a modern gaming TV is available here.