In the theatrical release, the color wandered all over the place, even looking green in some effects shots (poorly corrected that is; the actual suit was green in some cases, they had dozens of different suits for different uses).
The DVD that came out a few years ago fixed that for the most part, and the suit remains properly blue.
But blue is a hard color to pin down, and Superman's suit, in the movies, comics and action figures - has been portrayed as a wide range of values.
- k