TCL C8L / QM8L vs LG OLED B6

When it comes to HDR, the TCL C8L turns out to be a hellishly bright television – and I mean that literally. On a synthetic test pattern of 5%, our measuring equipment indicated a result exceeding 4500 nits. That's an almost cosmic result, considering that reference director's monitors, which we often refer to in our materials, usually operate around 4000 nits. Does this mean the C8L breaks barriers and climbs to the technological peak of Mini-LED? Not quite. Dry synthetic tests are one thing, and real film images are another. In real, varied scenes, the C8L hits around 1600 nits at its peak. That's still a very good result, ensuring a very high level of HDR dynamics, but it's clearly lower than what the manufacturer boasts in the specifications. The trouble begins with very small bursts of light – then the brightness can drastically drop to around 600 nits. The algorithm does everything it can to maintain deep blacks and minimise halo effect, but it does so at the cost of HDR impact. This is ideal evidence that laboratory test patterns rarely correlate with what we ultimately see on the screen.

Huge applause is due for colour 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 jaw-dropping measurements come from the notoriously demanding BT.2020 space. The C8L achieves an impressive 90% in this area, placing it alongside today’s top screens that feature RGB backlighting. Importantly, unlike some screens with Micro/Mini RGB backlighting, this effect is stable regardless of the scene being displayed. Of course, it’s important to remember that content mastered for such a wide gamut in films or series is still a rarity. However, the very fact that the panel has such a "reserve of colours" deserves huge admiration.

LG B6 is a moderately bright OLED. After calibration it reaches around 800 nits, roughly 200 nits more than last year's B5. That's down to LG Display's new budget OLED SE panel. In practice this simply provides a bit more headroom and makes HDR look fuller in many scenes than on last year's lower-end OLEDs. That doesn't mean the B6 has no limitations. In very bright shots, when a large part of the screen is brightly lit, brightness can fall below 400 nits. This behaviour is typical of OLED TVs (especially in this segment), and it's then you see the biggest difference compared with pricier models. All the same, we rate the B6's results as really solid. It's still not a TV built to break brightness records, but the HDR effect is strong enough that films really feel like a step up from ordinary SDR picture.

Colour gamut

Using the OLED SE panel has had some impact on wide colour-gamut coverage. Compared with last year's model the figures have dropped by a few percentage points. DCI-P3 reaches about 96%, and BT.2020 around 71%. That doesn't mean the colours on the LG B6 are weak. In most films and TV series they look vivid, well saturated and simply pleasing to the eye. You only notice the difference in very bright, highly colourful scenes. Then colours lose some intensity compared with QD-OLED panels. This is due to the WOLED panel structure. In addition to the red, green and blue subpixels it also uses a white subpixel that helps boost brightness. This comes at a cost: at very high luminance some of the colour is effectively 'diluted' by the white light, so saturation of some hues can be slightly lower. Day-to-day it's not a big problem, but you can see it in the most demanding scenes.

We tested the TCL C8L in the best factory mode available in the TV's menu for picture fidelity. I’m of course talking about Filmmaker Mode, which was introduced into this brand’s software relatively recently (a year ago in the K series). Thanks to it, the average user can get pretty good colour reproduction straight out of the box, although it’s certainly not perfectly tuned. Looking at the factory white balance of our unit, in both SDR and HDR content, there was a clear lack of the red component, which made the picture noticeably cooler and slightly shifted towards bluish‑green hues. The issue of brightness management is also ambiguous, as we mentioned earlier. While in SDR content the linearity of the gamma parameter is really good and consistently holds the reference value of 2.4, things are much worse in HDR. Tracking the EOTF curve clearly shows the TV’s brightness is considerably boosted across the range, which can make the final image overly bright and inconsistent with the creators’ intent, and that is in a mode that by definition should avoid this. Of course, like every unit in our lab, this one was also subjected to professional calibration, and you can find the results below.

We tested the LG B6 in Filmmaker Mode, the best picture setting available straight out of the box. ISF modes give very similar results, but in our tests we always stick to Filmmaker Mode for better comparison with other TVs. Each of them is a far better starting point than Vivid or Eco, where the picture is heavily boosted and noticeably less natural. For SDR content the factory settings perform really well. Colour errors are small, gamma behaves correctly, and the picture looks natural during regular viewing and does not seem overly enhanced.

It's a bit worse with HDR. Once you start playing that kind of content it's quickly apparent the white balance isn't perfectly set. Too much blue and red makes the image take on a slightly pink tint. Colour gamut measurements and the ColorChecker confirm this, with samples clearly shifting in that direction. It's not a defect that completely ruins the picture, but you can notice it with HDR films. So anyone who wants the most faithful image should consider calibration, which we cover later in the review.

As you can see, the results of a professional calibration of the TCL C8L are genuinely promising, thanks to the extensive adjustment tools the manufacturer made available in the menu. Most importantly, we were able to fully correct the white balance, eliminating a lack of red so the image finally stopped drifting into unwanted, cool tones. After this step, errors in the ColorChecker test fell to near-reference values, regularly sitting below a Delta E threshold of 2, which is under the level noticeable to the human eye.

Since the test patterns look so 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 real film material (I recommend turning the EOTF filter on when watching films), it becomes clear that the TV in most scenarios still responds to HDR metadata in its own way. As a result, the image can be a touch too bright and not in line with the creators' intent, and it was precisely for this lack of repeatability with real-world films that we had to dock the C8L a few points.

During calibration we focused mainly on HDR material, because that’s where the factory settings needed the most correction. We didn’t neglect SDR, though. After tuning it was brought almost to perfection. Colours are very accurate and brightness is controlled as it should be. The biggest change in HDR came from improving the white balance. After removing excess red and blue the pinkish tint disappeared and the image became much more natural. Skin tones, whites and all colours that had previously leaned towards pink improved. After calibration most errors fell below Delta E 2-3, the threshold at which an average viewer stops noticing differences with the naked eye. So the LG B6 can produce a very accurate picture, especially for the manufacturer’s entry-level OLED model.

This year the C8 series and the higher-end models have probably received the biggest and most eagerly awaited upgrade in TCL's history, and it's to do with digital image processing. The C8L is the entry-level model in the manufacturer's line-up to be fitted with the latest flagship MediaTek Pentonic 800 chipset (shown in the menu as MT9655). It is thanks to its processing power that the feature called "Gradual Smoothing" finally works the way it should. The algorithm effectively removes unwanted posterization (ugly tonal transitions / colour banding) from the picture, 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 judging this element can be purely academic, because the differences between today's TVs in this class are very subtle. The most important point is that TCL finally has nothing to be ashamed of compared with the competition.

LG B6 copes very well with lower-quality material. Much of that is down to effective digital image processing, which can mask some source imperfections without excessively smoothing the whole scene. The "Smooth Gradation" feature proves particularly useful. It lets you noticeably reduce posterization mentioned earlier, especially in dark parts of the image. The safest choice is to set it to Low or Medium. The feature still effectively smooths out harsh tonal transitions, but doesn't yet interfere too much with fine details. Die-hard purists can of course leave it off. Upscaling to 4K also performs very well. Full HD and 720p content retain a fair amount of detail, and the image is neither overly sharpened nor heavily blurred. Some limitations are only noticeable with very poor sources below 720p, where the smallest text and fine elements aren't always perfectly sharp, but this is true for almost every other TV on the market.

The TCL C8L is equipped with a fast panel with a native 144 Hz refresh rate. That spec will be most appreciated by demanding PC gamers, while most users, relying on consoles or TV broadcasts, will use a steady 120 Hz. And it is at 120 Hz that the motion-processing algorithms take care of image processing for films, series and sports. In the TV's menu you'll find a "Motion Clarity" option that lets you customise the motion smoothing to your preferences. The algorithms handle both cinematic productions at 24 or 30 frames per second and fast-paced sports broadcasts at 50 or 60 frames per second, maintaining the right level of smoothness.

One of the biggest advantages of OLED panels is their very fast pixel response time. That keeps the picture sharp and prevents visible smearing that often appears on LCD TVs. It does have a downside, though. During slow camera pans motion can look a bit choppier than on LCD screens, where the slower panel naturally masks some of that effect. Fortunately, on the LG B6 this is easy to tame with TruMotion. With the motion smoothing set correctly you can get smoother motion without giving the picture an exaggerated soap-opera effect.

For gamers – especially for owners of powerful PCs and multiple consoles simultaneously – the TCL C8L is a true beast. This is the first model in this manufacturer's lineup that is equipped with four full HDMI 2.1 ports with a maximum bandwidth of 48 Gbps. This is directly due to the use of the new Pentonic 800 processor, which we've mentioned before. Additionally, the TV seamlessly supports practically every gaming feature. It has an automatic game mode (ALLM) that reduces latency to minimal levels, as well as full variable refresh rate (VRR) operating in an impressive range of up to 288 Hz. It also supports standards such as G-Sync and FreeSync from Nvidia and AMD. When it comes to image display standards, there are no compromises either: the C8L offers complete support for HDR formats in gaming, including gaming Dolby Vision and the HGiG profile. We can conveniently manage all these features from a very readable gamer bar (Game Bar), which we can customise according to our own preferences. From a purely gaming perspective, the C8L really has no flaws – well, maybe apart from the previously mentioned slight ghosting. But other than that? It’s a no-nonsense machine for gamers.

LG OLED B6 has plenty going for gamers; it's a complete base for the PS5, Xbox Series X/S or a solid PC. It comes with four full-size HDMI 2.1 ports with 48 Gb/s bandwidth, so you can forget about annoying cable swapping when you want to connect several newer devices at once. We get a full package of sync technologies, from classic VRR to G-Sync and FreeSync. The panel effortlessly syncs its refresh rate to the frame pacing produced by your console or graphics card. Of course ALLM is present: the B6 automatically recognises when a game is running and immediately cuts latency to a minimum. HDR support is also excellent. The TV supports Dolby Vision, and a correctly implemented HGiG means that after an initial calibration in the console settings the picture won't suffer from blown-out whites or lost detail in bright areas. The icing on the cake is the Game Bar. Instead of digging through the full menu mid-game, a single click lets you correct shadow visibility, tweak chosen parameters or simply check the display's current mode. All of this makes the LG B6 a great choice for gamers.