TCL C75B offers many picture modes, but in our opinion, the best choice is the "Film" mode. Although its settings are quite good, the television struggles with certain color reproduction issues. In tests, we noticed that the image had a noticeably pinkish tint compared to what could be considered correct. This effect was particularly noticeable in skin tones, which appeared unnaturally warm. The main culprit of this phenomenon turned out to be the white balance, characterized by an excessive amount of blue and red in both HD and 4K HDR materials.
Another issue was the way brightness was reproduced. The gamma, which is responsible for the visibility of details in darker materials, was definitely boosted, causing details in the darkest parts of the screen to be invisible, lost in total blackness (e.g., the bottom part of the screen in the comparative photo - the area around the actress's ear). Similarly, the situation was reflected in the EOTF curve, which was below the correct value, suggesting that a similar problem may be encountered in 4K HDR content.
Thanks to our experience and the appropriate tools, we decided to take matters into our own hands and see how much could be extracted from this model after professional calibration. Details are described in the next section.
Well, how does the television perform with colors straight from the factory, without any intervention from our side? The Haier K85F offers a full range of picture modes, such as Dynamic or Eco, but for anyone who wants to watch movies according to the creators' intentions, only one really matters: Film mode. This is the mode we focused our tests on, and unfortunately, its name has little to do with reality. The picture in the factory settings is far from what we could call cinematic fidelity and requires many adjustments. Let's start with the white balance, which has a clear lack of red color. In practice, this means that the whole picture has a cool, bluish tint. The situation is even worse when it comes to brightness management, specifically gamma curves (for SDR) and EOTF (for HDR). Their graph resembles a real rollercoaster, which has a disastrous effect on the viewing experience. This results in unnatural dimming of SDR content, causing details in the shadows to get lost, and in the case of HDR – excessive brightness, which further exacerbates the issue of highlights. This combination, meaning too cool white combined with chaotic brightness and excessive blue color saturation, causes enormous errors in color reproduction. Our measurements on a specialized ColorChecker chart showed errors (Delta E) regularly reaching and exceeding values of 8-9. In simpler terms: errors above the threshold of 3 are easily noticeable to the naked eye, so such a result means that the colors on the screen are simply heavily distorted.