TCL C8K is a really bright television. In synthetic conditions – that is, during tests with brightness charts – it was able to achieve even 3500 nits peak brightness in movie mode. That's an impressive result and brings the C8K close to the market leaders, at least when it comes to panel brightness. More importantly – these aren't just numbers on paper. In films with a lot of bright scenes, such as Life of Pi or The Meg, the brightness clearly exceeds 1000 nits, providing a true sense of HDR effect. The picture in those moments looks very dynamic, colors are saturated thanks to excellent coverage of the color palette, and the lights are – spot on and intense. Exactly how it should be.
However, this doesn’t mean that everything is perfect. Just like in contrast tests, here too, in more demanding scenes, compromises appear. In sequences with very fine light elements – such as stars in the night sky or reflections in dark rooms – the local dimming algorithm can… get confused. Instead of bringing those details up, the television sometimes decides to dim them significantly – down to around 300 nits – to maintain deep blacks. On one hand, this is quite a sensible approach (better deep black than a grey/navy blue screen), but on the other – there may be moments when certain elements of the picture become difficult to see or even disappear into darkness.
TEST UPDATE (20/08/2025): The brightness control algorithm in this model is quite problematic – attempting to calibrate the picture so that it doesn’t drastically overexpose the brightest scenes results in unnatural shifts: improvement in one part of the image results in deterioration in another. The television may achieve slightly higher readings in brightness measurements, but in practice, this comes with a heavily overexposed image that looks very unnatural!
For the record, we provide brightness values without this adjustment:
1463 nits
640 nits
1368 nits
468 nits
1025 nits
The biggest difference between the 65-inch S90F and the other versions is brightness. The QD-OLED panel can reach up to 1700 nits in laboratory tests, which is over 500 nits more than the version with a WOLED matrix. This translates to a significantly stronger and more immersive HDR effect. In most scenes, the bright parts of the image look stunning, and we must admit that we were positively surprised, as we expected results closer to the WOLED version, but what we got is an effect that impresses even in films. As with every OLED, there are moments when the panel must reduce brightness a bit. This mainly concerns full-screen, very demanding scenes – for instance, in the last test scene from the movie “The Meg,” brightness drops to around 800 nits. However, it's hard to consider this a flaw because it's still an excellent result, unprecedented in OLED TVs in this price range. Everything suggests that the 65-inch S90F could be one of the best choices this year for those looking for a strong OLED at a reasonable price. Another advantage of the QD-OLED matrix in HDR content is its colour gamut coverage. Thanks to quantum dots, the television achieves nearly 100% of the DCI-P3 gamut and almost 90% of the BT.2020 gamut. These are values that place it alongside much more expensive models and make it exceptional in its class.