TCL C8L / QM8L vs LG OLED C6 (WOLED)

In terms of HDR, the TCL C8L turns out to be a hellishly bright television – and I mean literally. On a synthetic chart of 5%, our measuring equipment indicated a result exceeding 4500 nits. This is a result that is downright cosmic, considering that reference director monitors, which we often refer to in our materials, typically operate around 4000 nits. Does this mean that the C8L breaks barriers and climbs to the technological peak of Mini-LED? Not exactly. Dry synthetic tests are one thing, and real movie images are another. In real, varied scenes, the C8L achieves a peak of around 1600 nits. This is still a very good result, ensuring a very high level of HDR dynamics, but also clearly lower than what the manufacturer boasts in the specifications. The trouble starts with very small flashes of light – then brightness can drastically drop to around 600 nits. The algorithm tries at all costs to maintain deep black and minimize halo effect, but it does so at the expense of HDR impact. This is perfect evidence that laboratory charts rarely correspond to what we ultimately see on the screen.

Huge applause is due for color 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 true jaw-dropper is the measurement of the extremely demanding BT.2020 space. The C8L achieves as much as 90% in it, placing it alongside today's top screens that boast RGB backlighting. Importantly, unlike some screens with Micro/Mini RGB backlighting, this effect is stable regardless of the scene displayed. Of course, one must remember that content mastered for such a wide gamut in films or series is still a rarity. However, the mere fact that the panel has such a "color reserve" deserves immense admiration.

The HDR effect on the LG C6 is really very good. LG Display's new WOLED panel primarily brought a significant increase in brightness. In our unit we measured around 1,500 nits and, importantly, the TV can show similar values in many normal movie scenes. That gives HDR the proper impact. Bright highlights, lamps, or sunlight can be really strong, and most HDR movies simply look very impressive. Of course it's still an OLED, so brightness drops in scenes with a lot of white. The fifth scene of The Meg illustrates this well, where the C6 reached about 600-700 nits. That's still a very good result, but it also shows the new panel hasn't removed all the limitations typical of OLEDs.

Colors

When it comes to color, there is also little to complain about. The C6 covers about 99% of the DCI-P3 gamut and roughly 75% of BT.2020. In practice the colors are very saturated and, importantly, stable regardless of the scene. That's worth emphasizing, because not every TV behaves the same in this respect. In some RGB Mini LED models color saturation can depend more strongly on image brightness. Today a wider color gamut is mainly offered by QD-OLED TVs and new SQD models with a new generation of quantum dots. However, the C6 still performs very strongly here and is able to generate appropriately saturated colors in most movie scenes.

We tested the TCL C8L in the best factory picture mode available in this TV’s menu for image fidelity. That, of course, is Filmmaker Mode, which appeared in this brand’s software relatively recently (a year ago in the "K" series). Thanks to it, an average user can get a pretty good color reproduction straight out of the box, although it is certainly not a perfectly tuned mode. Looking at the factory white balance of our unit, both in SDR and HDR material, the red component was clearly lacking, which made the image noticeably cooler and caused a slight shift toward bluish-green tints. The issue of brightness management is also ambiguous, as we mentioned earlier. While for SDR content the gamma linearity is actually correct and holds steadily at the reference value of 2.4, in HDR things look much worse. Tracking the EOTF curve clearly shows the TV has a significantly boosted brightness across the range, which can make the final image overly bright and inconsistent with the creators’ intent, and that in a mode that by definition should avoid that. Of course, like every sample in our lab, this one also underwent professional calibration, and its results are shown below.

Right out of the box the LG C6 is pretty well set up, especially if you choose Filmmaker mode. In SDR material the white balance is decent, although as brightness increases it starts to lack a bit of red. The picture becomes a little cooler as a result, but it’s not such a big difference that it stands out during normal viewing. More happens in the brightness response itself. Gamma is a bit low and instead of holding at 2.4 it sits closer to 2.1–2.2 over much of the range. In practice the C6 slightly brightens midtones. Shadows are therefore more readable, but the image loses some depth compared with how it should look in a dark room. In HDR the situation is a bit more interesting. The start of the grayscale looks very good, but from about 20–30% brightness the white balance starts to drift more and more. As brightness rises there’s more red and a noticeable lack of blue. In the brightest highlights the difference is already significant and also affects reproduction of some colors. The EOTF curve itself is handled fairly well over most of the range. The C6 only has a tendency to slightly brighten the image, which we also saw during our film comparisons. The largest deviation appears around the brightest highlights, where the TV begins to adapt the signal to the panel’s capabilities. So the out-of-the-box Filmmaker mode in HDR isn’t perfect, but overall it performs well. The biggest room for improvement is the white balance, especially at high brightness.

As you can see, the results of a professional calibration of the TCL C8L are really promising, thanks to the extensive adjustment tools the manufacturer put at our disposal in the menu. Above all, we were able to completely correct the white balance — we eliminated the red deficiency, so the image finally stopped drifting toward unwanted cool tones. After that adjustment, errors in the ColorChecker test fell to near-reference levels, regularly landing below a Delta E of 2, which is below the threshold of human perception.

If the test patterns look this perfect, you might ask: why then the lower final score in this category? The answer lies in the brightness management discussed earlier. Although the menu includes sliders that let you precisely straighten the EOTF curve on synthetic signals, when confronted with actual movie material (I recommend enabling the EOTF filter when watching movies), you can see that in most scenarios the TV still reacts to HDR metadata its own way. As a result, the picture can be slightly over-brightened and not faithful to the creators' intent, and it was precisely this lack of consistency with real films that cost the C8L a few points.

LG TVs have been very receptive to calibration for years, and the C6 is no exception. After adjustment the white balance was set almost perfectly, and most color errors dropped to values below 3, often even around 2. In practice this means very accurate color reproduction in both SDR and HDR. An interesting detail appeared only with the HDR brightness characteristic. On a classic EOTF chart everything looks nearly ideal, and at first glance it would be hard to find fault. Only when we measured the TV’s behavior using filters based on actual movie scenes did it become clear that the C6 has a slight tendency to artificially boost image brightness.

It’s not a huge difference and many people may even see it as a positive, because HDR looks a bit more impressive this way. From the standpoint of fidelity to the source material this isn’t ideal — some scenes are simply a touch brighter than the filmmaker intended. Interestingly, this is somewhat unusual for LG. In previous generations, the brand’s TVs typically stuck very closely to the reference tone curve after calibration. With the C6 we’re still very close to the standard, but that subtle boost in brightness is indeed noticeable in films and series.

This year the C8 series and higher models received probably the biggest and most anticipated upgrade in TCL’s history, and it specifically concerns digital image processing. The C8L is the lowest-end model in the manufacturer's lineup to be equipped with the latest flagship chip, the MediaTek Pentonic 800 (listed in the menu as MT9655). Thanks to its processing power, the feature called "Gradual Smoothing" finally works as it should. The algorithm effectively eliminates unwanted posterization (ugly tonal transitions/color banding), doing so intelligently enough that it does not degrade the sharpness of other details.

The processor also handles upscaling lower-resolution content to 4K very well. Although evaluating this element can be mostly academic, because the differences between today's TVs in this class are very subtle. The most important takeaway is that TCL finally has nothing to be ashamed of compared to the competition.

The LG C6 has taken a really big step forward here. The TV uses the same processor found in the flagship G6, and in terms of image processing the two models are very similar. That’s a big plus, because in this area LG’s processor this year performs excellently. The "Smooth Gradation" feature works especially well. With heavily compressed material it can effectively hide ugly tonal transitions and artifacts that often appear, for example, in lower-quality streaming. It’s best to leave it set to "Low." Then the improvement is clear, and the TV doesn’t yet start blurring fine details. Higher levels smooth the image more, but can already remove some of the natural texture of objects on the screen. The upscaling itself also performs very well. Lower-resolution content is sharpened properly, edges look clean, and the processor quite effectively rebuilds fine details. In this regard the C6 is already very close to LG’s best TVs, and the differences compared with the G6 are small.

The TCL C8L is equipped with a fast panel that has a native 144 Hz refresh rate. That spec will be most appreciated by demanding PC gamers, while most users, who rely on consoles or TV broadcasts, will use a steady 120 Hz. It is at 120 Hz that motion processing algorithms handle image rendering for movies, series, and sports. In the TV’s menu you’ll find a "Motion Clarity" option that lets you adjust the motion smoothing to your preferences. The algorithms handle cinematic material at 24 or 30 frames per second (fps) as well as dynamic sports broadcasts at 50 or 60 fps, maintaining appropriate smoothness.

The LG C6 features a panel with a maximum refresh rate of 165 Hz, which is great news especially for gamers using a powerful PC. For movies, sports, or consoles we'll of course use up to 120 Hz, but even then it's hard to fault the motion clarity. As you'd expect from an OLED, the panel's response time is almost instantaneous. Moving objects therefore don't leave the characteristic smears you still see on LCD TVs. This is particularly noticeable in sports and fast-paced games, where the picture remains very clean even during dynamic motion.

For movies and TV, LG also provides the TruMotion motion-smoothing system. In the user settings you'll find two separate sliders. De-Judder is mainly for low-frame-rate content, that is primarily 24 fps films and series. It can slightly reduce the characteristic judder, or be set higher if you want a much smoother image. De-Blur is useful for higher-frame-rate material, mainly sports broadcasts and 50/60 fps television.

For gamers – especially for those with powerful PCs and several consoles at the same time – the TCL C8L is a true beast. It’s the first model in the manufacturer’s lineup equipped with four full HDMI 2.1 ports with a maximum bandwidth of 48 Gbps. This is directly thanks to the new Pentonic 800 processor we wrote about earlier. Additionally, the TV seamlessly supports virtually every gaming feature. It has an automatic game mode (ALLM) that reduces latency to minimal levels and full frame synchronization (VRR) operating in an impressive range of up to 288 Hz. We’re also talking about standards like G-Sync or FreeSync from Nvidia and AMD. When it comes to image display standards, there are also no compromises: the C8L offers complete support for HDR formats in games, including gaming Dolby Vision and the HGiG profile. All of these features can be conveniently managed from a very readable game bar (Game Bar), which we can customize according to our preferences. From a purely gaming perspective, there really isn’t anything to complain about in the C8L – well, maybe aside from the previously mentioned slight ghosting. But other than that? It’s an unflawed machine for gamers.

LG has focused heavily on gamers for years, and the C6 really lacks nothing important. The TV supports 4K at 120 Hz from consoles, and when connected to a PC it can run up to 165 Hz. It also offers VRR from 40 to 165 Hz, ALLM, and properly working HGiG. A big plus is Dolby Vision support for games, so the Xbox Series X can use that format without sacrificing game mode. The package is rounded out by a Game Bar that lets you quickly check key signal parameters and change settings without leaving the game. In terms of features, the C6 is one of those TVs that’s really hard to find fault with. Whether you play on PlayStation, Xbox, or PC, practically everything you could expect from a modern gaming TV is available here.