TCL C6K vs TCL C8L / QM8L

TCL C6K is a moderately bright television that can showcase its full capabilities in the best movie conditions – the maximum brightness is around 600 nits. In scenes with large, intense light sources, the HDR effect can be truly satisfying, providing a sense of cinematic sparkle. However, it's important to remember that with local dimming management, there are situations where some elements become dimmed, and sometimes even barely visible. It is clear that there is a lack of proper optimization of the algorithms, although looking at the technical parameters in this price range, the build quality performs very well.

When it comes to HDR, the TCL C8L turns out to be a hellishly bright television – and I mean that literally. On a synthetic test pattern of 5%, our measuring equipment indicated a result exceeding 4500 nits. That's an almost cosmic result, considering that reference director's monitors, which we often refer to in our materials, usually operate around 4000 nits. Does this mean the C8L breaks barriers and climbs to the technological peak of Mini-LED? Not quite. Dry synthetic tests are one thing, and real film images are another. In real, varied scenes, the C8L hits around 1600 nits at its peak. That's still a very good result, ensuring a very high level of HDR dynamics, but it's clearly lower than what the manufacturer boasts in the specifications. The trouble begins with very small bursts of light – then the brightness can drastically drop to around 600 nits. The algorithm does everything it can to maintain deep blacks and minimise halo effect, but it does so at the cost of HDR impact. This is ideal evidence that laboratory test patterns rarely correlate with what we ultimately see on the screen.

Huge applause is due for colour reproduction, all thanks to the new generation of SQD (Super Quantum Dot) quantum dots. The coverage of the DCI-P3 palette reaches 97%, but the jaw-dropping measurements come from the notoriously demanding BT.2020 space. The C8L achieves an impressive 90% in this area, placing it alongside today’s top screens that feature RGB backlighting. Importantly, unlike some screens with Micro/Mini RGB backlighting, this effect is stable regardless of the scene being displayed. Of course, it’s important to remember that content mastered for such a wide gamut in films or series is still a rarity. However, the very fact that the panel has such a "reserve of colours" deserves huge admiration.

This year's TCL televisions have introduced the Filmmaker mode, and it must be said that it is definitely the best choice right out of the box. This is the mode we recommend for everyday viewing of movies and series. Unfortunately, as is often the case, the best does not mean perfect. In the case of SDR content, the image was too warm, as the red was quite prominent in the white balance. On the other hand, with HDR content, we had the opposite impression – the image became cooler than it should have been, due to an excess of blue. There is also the brightness characteristic, which at times led to overexposure. In practice, these issues combined resulted in quite noticeable errors in colour tests, which are hard to accept in a mode advertised as “by the creators”.

We tested the TCL C8L in the best factory mode available in the menu of this television for image fidelity. We are, of course, talking about Filmmaker Mode, which has only recently been integrated into the software structures of this brand (last year in the "K" series). Thanks to it, the average user is able to achieve quite decent colour reproduction straight out of the box, although it is certainly not a flawlessly tuned mode. Looking at the factory white balance of our model – in both SDR and HDR material – there was clearly a lack of red component, which made the image noticeably cooler and slightly veered towards bluish-green hues. The issue of brightness management is also ambiguous, as we mentioned earlier. While in SDR content, the linearity of the Gamma parameter is really correct and consistently holds to the reference value of 2.4, in HDR, the situation looks much worse. Tracking the EOTF curve clearly shows that the television has significantly boosted brightness throughout the range, which can result in an excessively bright final image that is inconsistent with the creators' intent – and this is in a mode that, by definition, should avoid this. Of course, like every unit in our lab, this one was also subjected to professional calibration, and you can find the results below.

Thanks to the white balance adjustment, we were able to significantly reduce the C6K's tendency to distort colours, which resulted in a very good end result. After calibration, we won't observe the effect of excessive warming of scenes in SDR or overly cooling the image in HDR. However, it is worth taking a closer look at the brightness characteristics. In SDR content, it's hard to have major objections – the picture looks really good, especially in older movies, TV shows, or material from YouTube. It performs significantly worse with HDR content. An analysis of the EOTF curve suggests that everything is fine, but in practice (EOTF in movies), the limitations of the construction become apparent. The television tends to excessively brighten the smallest fragments of the frame, and in other situations, it can overly dim the entire scene. The effect of calibration is therefore noticeable, and regarding colourimetry, the C6K has really gained a lot, but certain limitations resulting from local dimming and actually from its management by the C6K simply cannot be overlooked.

As you can see, the results of the professional calibration of the TCL C8L are truly promising, thanks to the extensive adjustment tools the manufacturer has made available in the menu. Above all, we were able to completely correct the white balance – we eliminated the red deficit, which means the image finally stopped drifting into undesirable, cool hues. After this adjustment, the errors in the ColorChecker test dropped to almost reference values, consistently placing below the Delta E threshold of 2, which is below the visibility limit for the human eye.

With the test patterns looking so perfect, you might be wondering: why then the lower final score in this category? The answer lies in the brightness management described earlier. Even though in the menu we find sliders that allow for precise straightening of the EOTF curve on synthetic signals, when faced with actual film material (I recommend turning on the EOTF filter in movies now), it becomes clear that the television reacts to HDR metadata in its own way in most scenarios. As a result, the image can be slightly brightened and inconsistent with the creators' intentions – and for this lack of repeatability in real films, we had to deduct a few points from the C8L model.

TCL C6K performs quite well in terms of upscaling. Lower quality materials appear acceptable, and the absence of overscan issues means the image is displayed in full, without cropping. However, one cannot expect miracles – very low quality content won't come to life here, as the image processor has its limitations. On thin lines or details, there is characteristic tearing visible, which indicates a lack of advanced image enhancement algorithms. It is also a shame that the C6K lacks the function of smoothing tonal transitions – in older films or video materials, colour banding can be noticeable and may be distracting during longer viewing sessions.

This year, the C8 series and higher models received probably the biggest and most anticipated upgrade in TCL's history, which pertains to digital image processing. The C8L model is the entry-level representative in the manufacturer's offer, equipped with the latest flagship chip MediaTek Pentonic 800 (marked in the menu as MT9655). It is thanks to its computing power that the feature called "Gradual Smoothing" finally works as it should. The algorithm effectively eliminates the unwanted phenomenon of posterization (ugly tonal transitions / banding of colours), doing so smartly enough that it does not degrade the sharpness of the remaining details.

The processor also handles upscaling lower-resolution content to 4K very well. While assessing this element can be purely academic, as the differences between today's televisions in this class are very subtle. The most important information in all of this is that TCL finally has nothing to be ashamed of compared to the competition.

TCL C6K uses a 144 Hz panel, which is a significant advantage in this price range. It's an important step forward in comparison to the previous model C655 PRO, which only offered 60 Hz in 4K. The difference is especially noticeable when watching sports or playing games – the ball, players, or fast action in the game are displayed more clearly and without losing detail. An interesting fact is the panel's ability to operate at 240 Hz, which the manufacturer doesn't mention in official materials. We will return to this topic when discussing the PC gaming mode.

TCL has also added a feature for movie watchers: "Motion Clarity," which allows users to adjust the image according to their preferences with two simple sliders. You can either keep the visible film frame or opt for a very smooth, almost theatrical effect. This way, everyone can find settings that match their taste.

TCL C8L has been equipped with a fast panel boasting a native refresh rate of 144 Hz. This specification will be appreciated primarily by demanding PC gamers, while most users – relying on consoles or television broadcasts – will utilise a stable 120 Hz. It is at 120 Hz that the motion processing algorithms handle image quality (in films/TV shows/sports). In the television's menu, we can find a section called “Motion Clarity”, which allows adjustment of the smoother to suit personal preferences. The algorithms perform well with both cinematic productions at 24 or 30 frames per second, as well as with dynamic sports broadcasts at 50 or 60 frames, ensuring appropriate fluidity.

The TCL C6K is a television that can confidently be called equipment designed for gamers. We have 4K at 144 Hz, VRR support, an automatic gaming mode (ALLM), and Dolby Vision Gaming. On top of that, there's a practical Game Bar, which is a panel with the most important settings handy – useful when we want to quickly change something during gameplay (e.g. screen ratio: Yes, you can!). Notably, it has a wide range of VRR, reaching up to 240 Hz. However, this option is mainly for PC gamers who drop below the native 4K resolution. In that case, the television can spread its wings and show additional smoothness, especially in fast e-sport titles. For consoles, we stick with the classic limit of 120 Hz, but the possibilities are still quite broad. The only slight drawback is some minor motion blur that can occasionally be seen in dynamic scenes. Other than that, the C6K offers everything gamers expect from a television.

For gamers – especially for owners of powerful PCs and multiple consoles simultaneously – the TCL C8L is a true beast. This is the first model in this manufacturer's lineup that is equipped with four full HDMI 2.1 ports with a maximum bandwidth of 48 Gbps. This is directly due to the use of the new Pentonic 800 processor, which we've mentioned before. Additionally, the TV seamlessly supports practically every gaming feature. It has an automatic game mode (ALLM) that reduces latency to minimal levels, as well as full variable refresh rate (VRR) operating in an impressive range of up to 288 Hz. It also supports standards such as G-Sync and FreeSync from Nvidia and AMD. When it comes to image display standards, there are no compromises either: the C8L offers complete support for HDR formats in gaming, including gaming Dolby Vision and the HGiG profile. We can conveniently manage all these features from a very readable gamer bar (Game Bar), which we can customise according to our own preferences. From a purely gaming perspective, the C8L really has no flaws – well, maybe apart from the previously mentioned slight ghosting. But other than that? It’s a no-nonsense machine for gamers.