LG OLED C4 vs TCL C9K

The HDR performance of the LG OLED C4 is impressive, firmly placing it in the higher tier. Most films exceed 700 nits, delivering a highly realistic image. While none surpass the 1,000-nit mark, the combination of these results with the TV’s infinite contrast and perfect blacks significantly enhances the visual experience. The final scene, with a full-screen flash of sunlight, is slightly less bright than the others but still maintains a solid level of brightness. Another highlight is the excellent DCI-P3 colour gamut coverage, which ensures incredibly vibrant colours. The HDR technology in the LG OLED C4 delivers exceptional colour and detail reproduction. The dynamic tone mapping feature optimises brightness levels, ensuring ideal light reproduction in every scene, even in the most demanding high-dynamic films.

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 best factory mode on the tested television was "Filmmaker," which served as the basis for all evaluations. In terms of colour reproduction, this mode performed reasonably well; however, certain flaws significantly detracted from the overall viewing experience. The most fundamental issue was the white balance, which exhibited a noticeable dominance of red, skewing the image characteristics. This resulted in a pronounced yellow tint to whites and a general shift of all colours towards warmer tones.

The gamma, an equally crucial—if not more important—aspect, was notably lowered, leading to a marked reduction in contrast. Additionally, the television frequently lost detail at the start of the gamma curve. These issues were most apparent in SDR content.

When examining HDR materials, the same yellowing effect in the white balance was observed, as seen with SDR content. However, the EOTF curve, which replaces the gamma curve for HDR, was near perfect and left little room for criticism.

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.

As mentioned, LG televisions come with advanced tools to facilitate an accurate calibration process. By utilising these tools, we meticulously adjusted the image to align with the director’s original vision. Without overstating, the results were outstanding. Both SDR and HDR content now achieve a level of visual fidelity that reflects how films are intended to be seen.

Examining the colour accuracy on the "ColourChecker" palette reveals impressive results, with almost all colour errors falling below a delta of "1," aside from two minor exceptions. Post-calibration, the LG OLED C4 demonstrated a marked improvement in colour reproduction, particularly in SDR and HDR modes. Testing the TV after calibration highlighted its capacity for delivering exceptionally accurate colours, underlining the high calibre of this model. The LG C41LA offers a stunningly precise colour palette, sure to satisfy even the most discerning viewers.

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.

Let us revisit the function responsible for smooth gradation and consider its role in improving lower-quality materials. The default smoothing of tonal transitions, while decent, can be further enhanced. The feature includes a slider for adjusting its strength, and we recommend selecting the first option. This setting strikes a balance, offering excellent results without compromising important details through unnecessary blurring.

The image scaling on the LG C4 is commendable, though not entirely without flaws. By default, the image appears slightly sharper, though not to an intrusive degree. While jagged edges on elements like trees are occasionally visible, this issue is relatively minor compared to similar offerings from other manufacturers.

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 G4 supports a maximum refresh rate of 144 Hz, achievable only when connected to a high-performance PC. Otherwise, the television operates at a maximum of 120 Hz, the recommended setting for viewing sports or content with fast-paced motion. For those prioritising smooth image quality, LG has included a versatile motion smoothing feature called "TrueMotion." This function is split into two adjustable sliders: De-Blur, which sharpens moving images, and De-Judder, which reduces jitter. Both sliders offer a range of settings from 0 to 10, enabling users to fine-tune the motion smoothness to their preference.

The LG OLED C4 boasts an impressive average response time of less than 1 millisecond, as confirmed by our measurements. This results in exceptional image clarity, far surpassing LCD televisions, which often have response times of several milliseconds. This clarity is evident in tests like the "UFO Test," where no trailing blur is visible behind moving objects.

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.

The LG C4, like nearly all OLED televisions from the manufacturer, excels in its compatibility with consoles and PCs. With the inclusion of four full-bandwidth HDMI 2.1 ports supporting 48 Gbps, the TV incorporates a range of features to enhance the gaming experience. Notably, it offers simultaneous support for FreeSync and G-Sync, making it an ideal choice for gamers using AMD or Nvidia graphics cards. For those seeking the best possible gaming quality, the integration of HDR Dolby Vision and HGIG mode is particularly impressive. HDR Dolby Vision operates with remarkably low input lag across all settings, ensuring smooth and responsive gameplay.

A standout feature in LG's televisions is the GameBar, which allows users to adjust settings in real-time without leaving the game. This includes options for customising the image for viewers with visual impairments, a thoughtful addition. Additionally, enabling VRR (Variable Refresh Rate) does not result in a loss of contrast—a benefit of the OLED panel's self-emissive technology, eliminating the need for conventional backlighting. While some slight flickering of grey tones may occur, this is a characteristic of VRR technology across all manufacturers.

In summary: The LG C4, like the brand's other OLED models equipped with high-refresh-rate panels and HDMI 2.1, provides a seamless and immersive gaming experience. For gamers demanding top-tier performance, this TV is an outstanding choice.

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.