TCL C9K vs LG OLED B6

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 LG B6 is a moderately bright OLED. After calibration it reaches around 800 nits, roughly 200 nits more than last year’s B5. That’s down to the new, budget OLED SE panel from LG Display. In practice it simply gives a bit more headroom and makes HDR look fuller in many scenes than on last year’s lower‑end OLEDs. That does not mean the B6 has no limitations. In very bright shots, when a large part of the screen is strongly lit, brightness can fall below 400 nits. This behaviour is typical for OLED TVs, especially in this segment, and that’s where you see the biggest difference compared with more expensive models. Even so, we judge the B6’s results as genuinely solid. It’s still not a TV for breaking brightness records, but the HDR effect is strong enough that films truly feel like a step up from ordinary SDR. Colour gamut Using the OLED SE panel has had a slight impact on wide colour gamut coverage. Compared with last year’s model the results have fallen by a few percentage points. It covers roughly 96% of DCI‑P3 and about 71% of BT.2020. That doesn’t mean the colours on the LG B6 are weak. In most films and series they look lively, well saturated and simply pleasing to the eye. You only notice the difference in very bright, highly colourful scenes. Then colours lose some intensity compared with QD‑OLED panels. This stems from the WOLED panel structure. Besides red, green and blue subpixels it also uses a white subpixel, which helps to boost brightness. However, this comes at a price. At very high luminance some colour is effectively 'diluted' by the white light, so the saturation of certain colours can be slightly lower. In everyday use this isn’t a major issue, but in the most demanding scenes you can notice it.

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.

We tested the LG B6 in Filmmaker Mode, the best picture setting available straight out of the box. ISF modes produce very similar results, but in our tests we always stick to Filmmaker Mode for better comparison with other TVs. Each of them is, in any case, a much better starting point than Vivid or Eco mode, where the picture is heavily boosted and noticeably less natural. On SDR material the factory settings perform really well. Colour errors are small, the gamma response is correct, and the picture during normal viewing looks natural and does not feel overly "pumped up". It's a bit worse with HDR. When such content is played you quickly see that the white balance hasn't been set perfectly. Too much blue and red gives the image a slightly pink tint. This is also confirmed by colour gamut measurements and the ColorChecker, where samples clearly shift in that direction. It's not a flaw that completely spoils the picture, but it is noticeable with HDR films. Therefore anyone who wants the most faithful image should consider calibration, which we cover further on in the review.

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.

During calibration, we concentrated mainly on HDR content, because that's where the factory settings needed the most correction. We did not, however, neglect SDR mode, which after adjustment was brought almost to perfection. Colours are very accurate, and brightness is controlled as it should be. The biggest improvement in HDR came from fixing the white balance. Removing the excess red and blue eliminated the pinkish tint, and the image became much more natural. Skin tones, whites and all colours that had previously shifted towards pink improved. After calibration most errors fell below a Delta E of 2–3, the threshold at which the average viewer stops noticing differences with the naked eye. So the LG B6 can deliver a very accurate picture, particularly for the manufacturer's entry-level OLED model.

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.

The LG B6 handles lower-quality material very well. This is largely thanks to effective digital image processing, which can mask some of the source’s imperfections without overly smoothing the whole scene. The "Smooth Gradation" function proves particularly useful. It noticeably reduces posterisation, especially in dark parts of the image. The safest choice remains the Low or Medium setting. The function still effectively smooths out unsightly tonal banding, but does not yet interfere too much with fine details. Purists can of course leave it switched off. Upscaling to 4K also performs very well. Full HD and 720p material retain a good amount of detail, and the image is neither overly sharpened nor heavily blurred. Some limitations only become apparent with very poor sources below 720p, where the smallest text and fine elements are not always perfectly sharp, but this applies to almost every other TV on the market.

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.

One of the biggest advantages of OLED panels is the very fast pixel response time. This keeps the picture sharp and free of the visible smearing often seen on LCD TVs. However, there is a downside. During slow camera pans motion can look choppier than on LCD screens, where some of that effect is naturally masked by the slower panel. Fortunately, on the LG B6 this can be easily mitigated using the TruMotion system. With the motion smoothing set correctly you can achieve smoother motion without giving the picture an exaggerated soap opera effect.

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 OLED B6 has plenty to offer gamers; it’s simply a complete base for PS5, Xbox Series X/S or a capable PC. It has four full-size HDMI 2.1 ports with 48 Gbps bandwidth, so you can avoid irritating cable swapping when connecting several newer devices at once. It offers a full suite of synchronization technologies, from standard VRR to G-Sync and FreeSync. The screen synchronises the refresh rate seamlessly with the frame output from the console or graphics card. Of course it includes ALLM: the B6 automatically recognises when a game is running and immediately reduces latency to a minimum. HDR support is also excellent. The TV supports Dolby Vision, and a correctly implemented HGiG standard means that, after initial calibration in the console settings, the image won’t suffer from blown-out highlights or lost detail in bright areas. The cherry on the cake is the Game Bar. Instead of digging through the full menu during gameplay, a single click is enough to adjust shadow visibility, tweak selected parameters or simply check the current display mode. All of this makes the LG B6 an excellent choice for gamers.