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 Hisense U7S has considerable HDR potential, but it can’t make full use of it in every scene. On a test pattern it reaches about 1100 nits, so the backlight is genuinely strong. In our brighter film scenes we measured around 640 to 745 nits. That’s still enough for the sun or bright highlights to have a distinct bloom and to show an advantage over SDR material. When the TV needs to light a larger portion of the image, it handles it quite well.
The problem appears with small lights on a dark background. Each of the 192 zones covers an area considerably larger than a tiny point on the screen. If the TV were to drive such a zone strongly, it would brighten the surrounding area along with the light. Hisense tries to avoid that and dims the whole zone. Blacks look better as a result, but a small bright object that should draw the eye also loses intensity. That’s why in two tougher scenes we recorded only 297 and 154 nits. The difference is large: in one shot HDR can impress, and in the next small highlights are noticeably muted. The U7S therefore prioritises keeping deep blacks, even at the expense of bright details. With this number of zones it’s an understandable compromise, but it’s worth remembering that the peak 1100 nits tells us about the backlight’s capability, not how brightly the TV will show every element of a film.
Colours
Hisense markets the U7S as ULED, but that’s a marketing name; the wider colour gamut here is achieved by a PFS phosphor backlight. In our measurements the TV covered about 91% of the DCI-P3 space and 71% of BT.2020. Those are good results, though a little short of the best screens on the market. The biggest shortfall is in green — the TV doesn’t even reach the DCI-P3 boundary there, so the most intense green hues will be less saturated than they should be. Most colours in HDR films and series still look suitably vivid, however. A positive is the repeatability of the results: gamut coverage on test patterns and in film scenes is practically identical.