TCL C855 vs TCL C9K

TCL C855 delivers a highly varied HDR effect. On one hand, the television truly shines, while on the other, it resembles a lower model with FALD backlighting. This situation is, however, regularly observed in this brand, so it was not a surprise to us. The first and last scenes, featuring large elements of light, look almost phenomenal, "shining" with brightness levels of 1470 and 1820 nits respectively. Such effects will certainly cause more than one person to squint, while simultaneously feeling the extraordinary dynamism of the scene itself. You can truly feel as if you are inside the film. The situation changes dramatically when small or minor elements with high luminance surrounded by black appear on the screen. The TCL C855, in order to avoid the halo effect, significantly reduces brightness to a level of even 240 nits, which is a disappointing result, causing the film to not appear as if it was recorded in HDR. The HDR effect in the TCL C855 makes watching dynamic scenes more engaging, allowing the viewer to feel as though they are part of the action. Even with smaller elements of high luminance, the television manages to maintain details without excessive dimming. Moreover, the TCL C855 test shows that the brightness of the image is adjusted for scenes with a large amount of detail, which enhances viewing comfort.

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 best factory mode for the TCL C855 is "Film," and it is on this mode that we conducted all our tests. Like any mode predefined by the manufacturer, it had its drawbacks that are worth correcting to achieve an image as close as possible to what the film producer intended. We will examine the colour characteristics in both SDR and HDR materials. Looking at the first, we see a noticeable dominance of green in the white balance, which, as you might imagine, resulted in an unpleasant greenish tint across the entire image. Observing the very important gamma chart, which is responsible for the image's contrast, we see a significant deviation from the reference line marked at 2.4. From the left, we can observe a strong spike in the measured value, which at this point caused the image to be overly contrasted, merging details into a dark blob. This situation persisted for quite some time, up to 20% of the chart's value, before then dipping below the reference. This, in turn, meant a brightening of the image and a significant drop in contrast. The factory mode performed slightly better in HDR materials, as the white balance looked quite good, except for the second half, where green once again took precedence. Looking at the EOTF curve, which, unlike gamma, shows the rate of brightness increase, we see primarily two errors: the darkest scenes were too dark, and the brightest ones were overexposed. This was something we could also observe in the scene from the film "Pan" in the paragraph checking the TV's HDR.

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.

TCL, like the vast majority of manufacturers, provides advanced calibration tools in its televisions. Here we find 2- and 20-point adjustments for greyscale as well as an advanced colour management system. The results, as you can see, are very good, and in SDR materials we have significantly approached the reference image. We eliminated both the green tint and the gamma issue, although there is still a slight "kink" at the very beginning. The performance with HDR materials was somewhat poorer, as the TCL C855 did not allow us to model them adequately. We were only able to slightly adjust the EOTF curve and significantly improve the colours themselves.

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.

Once again, we will take a look at the function of smoothing tonal transitions, but this time also at image scaling. The latter is particularly important when watching lower-quality materials, such as certain television programmes or older films. We will focus on the function responsible for tonal transitions. Interestingly, just like in the scenes of the previous test, it performed excellently and smoothed out practically all the inconsistencies; however, here it had problems. Using the menu responsible for this function, we found that no setting - even the strongest - was of any help.

Image scaling in TCL C855 is described as one of the best we have had the opportunity to test so far. The image is sharp, but in a way that could be described as natural for our eyes. Even the small, fine branches do not have jagged edges, and there is no white halo around figures, which is characteristic of inferior scaling systems.

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 maximum refresh rate we can set on the TCL C855 is 144 Hz. Naturally, this is only possible by connecting the TCL C855 television to a very powerful PC. Otherwise, we will be operating at a maximum refresh rate of 120 Hz, which is recommended if we primarily want to watch sports or content with a lot of motion dynamics. For those requiring high image fluidity, the manufacturer has implemented a multi-stage motion smoother. This has been divided into two separate sliders regulating the sharpness of moving images (Motion Blur Reduction) and flicker (Flicker Reduction). Both sliders can be set in the range from 0 to 10, with each increment affecting the level of smoothing, so everyone can find their sweet spot. We present a setting that allows for slight smoothing without the soap opera effect.

The panel of the TCL C855 features a very good response time. This is particularly important as VA panels often have issues with so-called ghosting, which is the effect where a black halo can be seen behind a fast-moving object.

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.

The TCL C855 television is equipped with full HDMI 2.1 connectors with a full bandwidth of 48 Gb/s. During our tests, we confirmed the seamless operation of all functions that are part of this standard. As can be seen, all checkboxes light up green, which will certainly be appreciated by gamers, both console and those using the television as a monitor for their computer. Additionally, the TCL C855 supports both AMD FreeSync and NVIDIA's G-Sync, which can be easily activated in the graphics card settings. Those with a very powerful setup can send a 144 Hz signal to the C855, which this television handles effortlessly. It is also worth mentioning the implementation of the HGIG mode, which, however, due to the flaw of the “Game” mode, is overly brightened, making it difficult to configure properly on screen. Fortunately, the television performs excellently with the Dolby Vision format.

The TCL C855 is one of the first manufacturers to equip its televisions with a special GameBar, which allows for extensive setting changes on the fly, without the need to exit the game. It features functions such as an additional crosshair grid, black level correction, and settings for people with disabilities. In the picture, we can see the next generation of this solution.

In summary, the TCL C855 television will be an ideal solution for those seeking a screen for all sorts of electronic gaming. Thanks to all the features supporting such entertainment, it is incredibly engaging. It is also important to highlight the very low input lag, regardless of the selected settings, including with the HDR Dolby Vision format.

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.