There was and is nothing wrong with the films. Each frame of an 8mm film is the size of a pinky nail. It's going to capture about as much as is to be expected, which is not much compared to 35mm and on up.
Nix was a blue-collar worker who knew absolutely nothing about film - he simply was there that day to capture the president going by, just like he was there at his house the week before capturing his family at a party. The same with Zapruder and Muchmore. Nix - and the rest of them - wouldn't have the film background to make such a profound statement as "...the film looked different."
Keep in mind, too, that this was *film* - a very organic way of capturing motion. If the original looked one way and a copy of it looked different, it's to be expected. There was nothing sinister about it.
As I've said ad nauseum numerous times, the films were NOT tampered with. The Z film actually proves that there was a conspiracy - there is no way in hell anyone could have pulled off the sharpshooting feat that Oswald was accused of doing. The Nix film merely confirms the Zapruder film, that neither was tampered with in any way as seen in this excellent sync of the two films.
This comparison is repeatedly ignored over and over and over again as "big deal." It actually IS a big deal and debunks so much BS I've read about elsewhere about the films being tampered with, about frames being removed, about the Z film being shot at 18 FPS then changed mid-sequence to 48 FPS, then 67% of the frames removed. It's all ridiculous.
