caolz Yes, I have changed the Nighttime Screen Brightness in 0. That works fine. At 0 there is less light and at 100 there is more light. But I need that in 0 generate less backlighting. That's what the control of my first photo is supposed to be for. But it doesn't make any difference. 15, 30, 60 is the same. My unit is dudu 7 yl888.