There are some buggy things with the scene files. Sometimes they are in effect and other times they are disabled. This is only noticeable with custom color files. I can't get a consistent situation that I can report, so it still comes and goes. Just a really poor implementation.
It could also be the "shaded with reflections" that is coming up default. Then the material properties really makes a difference.
I do a lot of work that requires good clear shaded images to get the idea across. I am always having to adjust things to have them come out bright enough or not too bright. Just going to perspective dulls everything.