I literally came to ask a similar question as I have done a side by side comparison with the original 2011 Blu ray and the dremasters.
Granted I am watching the dremaster on my 1080p phone (not sure if the phone is automatically downscaling it from 4k to 1080p through the google photos app?) but I did definitely notice less grain in the dremaster compared to 2011 Blu ray remaster.
I have also played the file on my 1080p tv and noticed the same reduction in grain.
I understand the original notes for the dremaster say it will “cleanup” the grain but I would be curious to have the 1080p edition before the upscaling process to 4k. 🤷
I never heard anything about this project saying that it will “cleanup” the grain, but that’s not my main concern.
What really concerns me is how upscaling can accidently redraw details in the picture without enough data to guide it.
The shot where Sam greets his daughter is a good example. I did a comparison of that picture in the ROTK 4K Dremastered thread, with the picture used in the Caps-A-Holic website. The pictures don’t match perfectly due to them coming from different frames, but they match well enough for me to notice how the patterns on the door archway of Sam’s house are interpreted differently in the 4K Remaster.
The patterns on the door archway in its native resolution (or in 1080p) still look a little blurry, so without enough data to interpret what the patterns look like, it looked like the program used to upscale the footage had no choice but to make a guess.