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
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.