TCL C9K vs Philips OLED770

As we mentioned regarding black levels 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 can achieve... 4000 nits of brightness! It sounds out of this world, but – and here's where the pattern unfortunately repeats – the numbers say one thing, and the practical experience says another. In real movie scenes, the situation looks different. In the best-case scenario, when light effects occupy a large part of the image and the local dimming algorithm doesn't have to ponder too much about what to do with thousands of zones, the effect is really quite good. At that point, the C9K can hit around 1500 nits, which delivers a pleasant, intense burst and can indeed leave a positive impression.

The problem arises 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 to as low as 400–500 nits. That's a huge difference from the potential 4000 nits we saw in lab tests. Why does this happen? Most likely, the television is trying to protect the black levels in this way and minimize the halo effect around bright objects. Unfortunately, this comes at the expense of detail – some details simply vanish, and the scene loses its nature.

The Philips OLED770 doesn't try to compete with the brightest OLEDs on the market, and it's actually hard to expect that, as it's the entry-level model in Philips' range for 2025. In our measurements, it reached a maximum of around 700 nits, which allows for enjoyment of HDR effects in scenes where light appears in spots – for instance, in the flash of headlights or a starry sky. In such moments, the picture can truly amaze. However, it's different when there are more bright elements on the screen. The TV, like many cheaper OLEDs, restricts luminance at that point, and the entire image noticeably dims. This was best seen in a scene from the movie The Meg, where the sun rises behind an oil platform – the brightness dropped to around 250 nits, which is almost three times less. The HDR effect remains pleasing to the eye, but it's worth being aware that this model performs best in scenes with less intense light. Fortunately, the OLED770 also has an ace up its sleeve – the coverage of the DCI-P3 colour palette is as high as 99%, so colours in movies and games are vibrant and very close to what the creator intended.

For colour tests, we once again reached for the Filmmaker mode – a new feature in TCL televisions for 2025. While the direction is a step in the right way, the execution leaves a lot 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 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 – brightness management. Regardless of whether we were watching SDR or HDR content, the image tended to wash out the entire scene, giving it an unnatural, almost grotesque character. Therefore, it’s hard to call this a "director's mode" – because no director has ever seen such an image.

The first measurements already show that the factory settings of the Philips OLED770 have a lot to improve, even in Filmmaker mode. The white balance chart clearly indicates a lack of blue, giving the image a slightly yellowish tint. In practice, white is not snow-like, but leans towards warmer hues – which some may even find appealing, but from a precision standpoint, this is a deviation from the norm. The gamma, on the other hand, tends to be on the darker side – the average value is around 2.6 instead of the reference 2.4. In mid-tones, the image appears muted and more saturated, which can look too "cinematic" but detracts a bit from the naturalness. However, the most significant issues are visible in colour reproduction. The average error is relatively high, and some colours – particularly shades of grey – deviate significantly from what should be seen. In everyday viewing, this means that sometimes colours may look less natural than we would wish.

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 on 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 brightness management also managed to be brought into order in SDR content, and the effect was more than satisfactory. 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 darkened the darkest parts too much. Just like we saw in the scene from the movie Billy Lynn. Colour-wise, the improvement after calibration makes a great impression, but brightness management in HDR remains the Achilles' heel of the C9K and presents a certain technological limitation.

Philips OLED770 had shown signs from the start that it harboured significant potential, but it was hard to fully appreciate this in its factory settings. The image was often too warm, and some colours appeared as if they had lost their naturalness along the way. Calibration revealed that this television was very amenable to work – it responded to every adjustment and almost immediately unveiled another layer of its capabilities. The white balance was set in both SDR and HDR so that the yellowish haze disappeared and a neutral, clear white emerged. Gamma stabilised closer to perfection, which helped restore the naturalness of mid-tones, while shadows ceased to be artificially darkened, perhaps even with a slight brightening effect. The result was obvious... Movies are watched with greater ease; the image has cinematic depth without the feeling that something is overly darkened. However, the most interesting aspect was working on the colours. Factory errors were not dramatic, but slightly noticeable – skin tones could be too warm, and grey wasn’t always the shade we expected. After calibration, the error values dropped to around 2, and in many cases even below 1. This is a level that is definitely lower than the threshold of discernibility for the human eye. In other words, after correction, the colours finally “clicked” into place. Looking at the screen, we felt like the television had begun to speak with a full voice. Like an instrument that had finally been properly tuned.

Digital image processing on the TCL C9K is rather average. The smooth tone transition feature seems to be present, but activating it practically changes nothing – colour bands are still visible, and it can unintentionally highlight elements we’d rather keep hidden, such as object textures. Fortunately, it doesn’t remove film grain, but that’s poor consolation given that the effects are still meagre. It’s therefore hard to recommend using this option.

On the other hand, image scaling presents itself much better. Lower quality materials look quite decent – characters and backgrounds are rendered clearly, although of course, with sources like 576p, the laws of physics cannot be fooled. Occasionally, there’s characteristic edge distortion of objects, but that’s the fault of the source itself, not the algorithm. A plus for not having issues with overscan – the image isn't artificially cropped or enlarged.

The problem of the previously mentioned colour connections can largely be mitigated thanks to the "distortion reduction" function, which is an algorithm for smoothing tonal transitions in Philips. It works best at a low level – effectively eliminating unwanted colour bands while not introducing strange artifacts or losing image detail. This is one of those features that is truly worth keeping on.

The issue of upscaling is somewhat less impressive. Images from lower resolution can be too soft, while in some parts the characteristic "jaggies" appear. The impression is that the algorithm is trying to reconcile two contradictory directions – smoothing and sharpening – and ultimately fails to find the golden mean. As a consolation, it's worth noting that the television does not have problems with overscan, meaning it does not cut off the edges of the image, which can sometimes happen in other competing models.

Similar to the C8K, the C9K is also a really fast TV – both figuratively and literally. It features 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 image looks very smooth and clear. Additionally, in movies, we get an extra motion smoother called Motion Clarity, which allows you to adjust the smoothness to your own preferences – from cinematic "judder" to almost theatrical smoothness.

The issue of the panel 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. This sounds like great news – because 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 blurring or smearing, ideal for both dynamic games and sports broadcasts. The problem only arises at 144 Hz. Unlike models with official support for this frequency, here we see the phenomenon of so-called frame skipping. This means that the television is unable to display all the frames – some of them are skipped, causing motion to lose smoothness and double outlines to appear on the screen. The effect resembles the operation of the BFI function, which Philips does not offer in this model anyway.

From a gaming perspective, the TCL C9K is a complete tool. It features two (out of four) full bandwidth 48 Gbps HDMI 2.1 ports, 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 that allows you to quickly check the most important parameters and adjust settings without fumbling through menus. Also, TCL's policy is a plus – the TV isn’t 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 plenty of freedom.

If someone is looking for a TV for gaming, the Philips OLED770 is a candidate that's hard to overlook. The mere fact that this is an OLED gives it a great starting point – perfect blacks and infinite contrast make evening sessions in atmospheric games look like they've been taken straight out of a cinema. Added to that is the Ambilight system, which uses LEDs on the back of the TV to extend the image onto the wall behind the screen. The effect is such that even just playing FIFA can look like a small spectacle, and in horror games, the atmosphere becomes really thick. On the technical side, 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 for those using an Xbox Series X, Dolby Vision support in games is also available. You just need to know that in this mode, the input lag is slightly higher than standard, although still at an acceptable level. As a bonus, we also get the 'Game Bar', which is a special tool strip for gamers. It's not the most conveniently designed solution, but it allows for a quick view of key parameters without exiting the game. Overall, this gives a picture of a TV that has all the most important gaming features on one hand, and on the other can add something unique – Ambilight. And it's this mix of technology and visual effect that makes the OLED770 one of the better screens for gaming in a home environment.