wanted to share some Samsung HDR experience with the group. I have a NU7100 (firmware 1251.0, picture mode=movie) and spent hours trying to get good HDR performance but the colors seemed slightly off, and the light level was too low. I tried many combination of color, contrast, ... settings to no avail. finally I set all numeric picture settings back to the default numbers, set color tone to warm1, contrast enhancer to LOW, and st2084 gamma value to +3. this made the colors look accurate and vibrant and stunning, just like HDR is supposed to be. These settings look great on several devices (including M7500 plaiying Alita: battle angel and apple TV 4K playing blade runner 2049), I had to back down to gamma +1 for the firestick 4K because higher gamma numbers were too bright in you tube and raised gray levels too much for prime video. my theory is that with contrast enhancer = OFF the TV was not performing color mapping or maybe choosing rec709 color space instead of rec2020 (even though I had color space = Auto). not sure if this issue just affects my model, or all Samsung TVs. if you are having HDR issues (too dark, seems like a gray filter is on, colors are muted, ...) give this a try.