I took some photos of what I mean.
I used a DVD of Frasier, a show with pretty modest colors. Here they look pretty good. This DVD player for some reason has a higher black level than true black (confirmed on other TVs) but everything else looks good.
Here is where the problem is. The red shirt is too red.
The same scene with color at 0. There isn't a green tint in real life. You can see details in the shirt that you can't see with color.
If these photos are bad, I'll take some better ones. My phone doesn't have the best camera.
The picture is not dim, and is quite sharp. The smearing goes away with color down. My conclusion is that the tube has some life left, I just need to find the right color level. No jailbars, softness, one side brighter than other etc.