TCL C9K vs Philips OLED770

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 Philips OLED770 does not attempt to compete with the brightest OLEDs on the market, and it would be difficult to expect that, as it is the entry-level model in Philips' range for 2025. In our measurements, it reached a maximum of around 700 nits, which allows enjoyment of HDR effects in scenes where light appears sporadically – for example, in the flash of headlights or a starry sky. In such moments, the image can truly be stunning. However, it is different when there are more bright elements on the screen. The television, like many cheaper OLEDs, limits luminance in those situations, causing the entire image to noticeably dim. This was best observed in a scene from the film The Meg, where the sun comes out behind an oil rig – the brightness then dropped to around 250 nits, which is almost three times less. The HDR effect remains pleasant to the eye, but it is worth being aware that this model performs best in scenes with less intense light. Fortunately, the OLED770 has a trump card – the coverage of the DCI-P3 colour gamut is as high as 99%, so colours in films and games are vivid and very close to what the creator intended to convey.

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.

The first measurements already show that the factory settings of the Philips OLED770 have quite a lot to improve even in Filmmaker mode. The white balance chart clearly shows a lack of blue, resulting in a slightly yellowish tint to the image. In practice, the white is not snowy but leans towards warmer tones – which some may even appreciate, but from the perspective of accuracy, this is a deviation from the norm. The gamma, on the other hand, tends to the darker side – the average value is around 2.6 instead of the reference 2.4. In the midtones, the image appears subdued and more saturated, which may seem too "filmic," but detracts somewhat from naturalness. However, the most issues are evident in colour reproduction. The average error is relatively high, and some colours – particularly shades of grey – deviate significantly from what one should see. In everyday viewing, this means that sometimes colours may look less natural than we would like.

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.

The Philips OLED770 from the outset signalled that it harboured significant potential, but in its factory settings, it was difficult to see this fully. The picture was often too warm, and some colours appeared to have lost their naturalness along the way. Calibration, however, revealed that it is a very responsive television – it reacted to every adjustment and almost immediately unveiled another layer of its capabilities. The white balance could be set in both SDR and HDR to eliminate the yellowish tint and introduce a neutral, clear white. The gamma stabilised closer to perfection, allowing midtones to regain their naturalness, and shadows stopped being artificially darkened, perhaps even with a slight brightening effect. The result was obvious... Films were watched with greater ease; the picture had cinematic depth, but without the feeling that something was exaggeratedly darkened. However, the most interesting aspect was the work on colours. Factory errors were not dramatic but slightly noticeable – skin tones were sometimes too warm, and grey didn’t always have the shade we expected. After calibration, the error values dropped to around 2, and in many cases even below 1. This is certainly a level lower than the threshold of human perception. In other words, after correction, the colours finally "clicked" into place. Looking at the screen, we had the impression that the television had begun to speak with its full voice. Like an instrument that has finally been well tuned.

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 issue of the aforementioned colour banding can largely be mitigated thanks to the 'distortion reduction' feature, which is an algorithm for smoothing tonal transitions in Philips. It performs best at a low setting – effectively eliminating unwanted colour bands while not introducing strange artefacts or losing image detail. This is one of those features that is truly worth leaving switched on.

The situation is somewhat worse regarding upscaling. The image from a lower resolution can be too soft, while in some areas, characteristic 'jaggies' appear. The impression is that the algorithm is trying to reconcile two conflicting directions – smoothing and sharpening – and ultimately fails to find a happy medium. As a consolation, it can be added that the television has no issues with overscan, meaning it does not cut off the edges of the image, which sometimes occurs in other competing models.

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 issue of the matrix in the Philips OLED770 is not entirely straightforward. The manufacturer claims a 120 Hz panel, but our measurements showed that the screen can accept a 4K signal even at 144 Hz. That sounds like great news – after all, who wouldn't want an additional mode for PC gamers at this price? However, the reality turned out to be more complex. With 120 Hz content, the television behaves like most OLEDs – the image is absolutely clear, with no trace of ghosting or blurring, making it perfect for both dynamic games and sports broadcasts. The problem only arises at 144 Hz. Unlike models with official support for this frequency, here you can observe the phenomenon known as frame skipping. This means that the television cannot display all the frames – some are skipped, causing motion to lose smoothness, and double contours appear on the screen. The effect resembles the operation of the BFI function, which Philips does not offer in this model anyway.

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.

If someone is looking for a television for gaming, the Philips OLED770 is a contender that is hard to ignore. The mere fact that we have an OLED here provides an excellent starting point – perfect black and infinite contrast make evening sessions in atmospheric games look as if they were lifted straight from the cinema. On top of that, there is the Ambilight system, which consists of LEDs on the back of the television that extend the image onto the wall behind the screen. The effect is such that even playing FIFA can look like a small spectacle, and in horror games the atmosphere becomes truly thick. From a technical standpoint, it's also quite decent. The Philips OLED770 supports variable refresh rate (VRR) up to 120 Hz, has an automatic mode for gamers (ALLM), and if someone is using an Xbox Series X, they can also count on Dolby Vision support in games. One must only know that in this mode the input lag is slightly higher than standard, though still at an acceptable level. As a bonus, we get the “Game Bar” panel, which is a special tool bar for gamers. It isn’t the most conveniently designed solution, but it allows you to check key parameters without leaving the game. Overall, this results in a television that, on one hand, has all the essential gaming features, and on the other, can add something unique – Ambilight. And it is this mix of technology and visual effect that makes the OLED770 one of the better screens for gaming at home.