TCL C9K vs LG OLED B6

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 LG B6 is a moderately bright OLED. After calibration it reaches about 800 nits, roughly 200 nits more than last year’s B5. That’s thanks to the new budget OLED SE panel from LG Display. In practice it simply gives a bit more headroom and makes HDR in many scenes look fuller than on last year’s lower-tier OLEDs. That doesn’t mean the B6 has no limits. In very bright shots, when a large part of the screen is strongly lit, brightness can drop below 400 nits. This behavior is typical for OLED TVs (especially those from this segment) and that’s when you see the biggest difference versus more expensive models. All things considered, we rate the B6’s results as really solid. It’s still not a TV for breaking brightness records, but the HDR effect is strong enough that you can really feel the step up from ordinary SDR in films.

Color gamut

Using the OLED SE panel has slightly affected wide color gamut coverage. Compared with last year’s model, results fell by a few percentage points. DCI-P3 reaches about 96%, and BT.2020 around 71%. That doesn’t mean the colors on the LG B6 are weak. In most movies and series they look lively, well saturated and simply pleasing to the eye. You only notice a difference in very bright, highly colorful scenes. Then colors lose some intensity compared with QD-OLED panels. This comes from the WOLED panel construction. Besides red, green and blue subpixels it also uses a white subpixel that helps boost brightness. It comes at a cost: at very high luminance some color is effectively “diluted” by the white light, so saturation of some colors can be slightly lower. In everyday use this isn’t a big issue, but you can notice it in the most demanding 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.

We tested the LG B6 in Filmmaker Mode, which is the best picture setting available right out of the box. ISF modes deliver very similar results, but in our tests we always stick to Filmmaker Mode for better comparison with other TVs. Each of those modes is, after all, a much better starting point than Vivid or Eco mode, where the picture is heavily boosted and noticeably less natural. With SDR content, the factory settings perform really well. Color errors are small, gamma behaves properly, and the image looks natural during ordinary viewing and does not seem overly "pumped up." It's a bit worse with HDR. When you play that kind of content you can quickly see that the white balance hasn't been set perfectly. Too much blue and red causes the image to shift toward a slightly pink tint. This is also confirmed by measurements of the color gamut and the ColorChecker, where samples clearly drift in that direction. It's not a flaw that completely ruins the picture, but you can notice it in HDR films. So people who care about the most faithful image should consider the calibration we describe later in the review.

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.

During calibration we focused primarily on HDR content, because that's where the factory settings required the biggest corrections. We didn't neglect SDR mode, though, which after adjustment was brought almost to perfection. Colors are very accurate and brightness is handled as it should be. The biggest improvement in HDR came from correcting the white balance. After removing the excess red and blue, the pinkish tint disappeared and the image became much more natural. Skin tones, whites and all colors that had been shifting toward magenta 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. The LG B6 can therefore deliver a very accurate image, especially for the manufacturer's entry-level OLED model.

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 B6 handles lower-quality sources very well. Much of the credit goes to effective digital image processing, which can mask some source imperfections without overly smoothing the whole scene. The feature "Smooth Gradation" proves particularly useful. It can significantly reduce posterization, which we mentioned earlier, especially in darker areas of the image. The safest choice remains Low or Medium. The function still effectively smooths harsh tonal transitions, but does not yet interfere too much with fine details. The most dedicated purists can, of course, leave it off. Upscaling to 4K also performs very well. Full HD and 720p content retain a good amount of detail, and the image is neither overly sharpened nor excessively blurred. Some limitations become noticeable only with very poor sources below 720p, where the smallest subtitles and fine elements are not always perfectly sharp, but this is true for almost every other TV on the market.

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.

One of the biggest advantages of OLED panels is their very fast pixel response time. This keeps the image sharp and prevents the visible smearing that often appears on LCD TVs. However, there is a downside. During slow camera pans, motion can look more choppy than on LCD screens, where the slower panel naturally masks some of that effect. Fortunately, on the LG B6 you can easily soften this with TruMotion. With the motion smoothing properly adjusted, you can achieve smoother motion without giving the picture an excessive 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 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 OLED B6 offers a powerful set of advantages for gamers; it's simply a complete platform for PS5, Xbox Series X/S, or a solid PC. It has four full-size HDMI 2.1 ports with 48 Gbps bandwidth, so you can skip the annoying cable swapping when you want to connect several newer devices at once. We get the full suite of sync technologies – from classic VRR to G-Sync and FreeSync. The screen seamlessly matches the refresh rate to the frame output produced by the console or graphics card. Of course ALLM is included: the B6 automatically detects a running game and immediately cuts input lag to a minimum. HDR handling is also excellent. The TV supports Dolby Vision, and a properly implemented HGiG standard means that after an initial calibration in the console settings the picture won’t suffer from blown-out highlights or lost detail in bright areas. The cherry on top is the Game Bar. Instead of digging through the full menu during gameplay, one click lets you adjust shadow visibility, tweak selected settings, or simply check the display’s current operating mode. All of this makes the LG B6 a great choice for gamers.