Star Trek IV is not a bad film, but I really feel the high esteem with which it's regarded is misplaced. It's a fun experience the first time around, but it's an artificial high that decreases significantly with every rescreening. Sharpness is one concern. Print defects mar the image mainly during effects shots, especially if there's a composite. At those times, we see fairly high levels of speckles and grit, whereas these issues are not a substantial concern during other parts of the film.
Colors generally appear accurate and natural, but a fair amount of oversaturation intrudes at times.
The general smoky murkiness of starship bridges also creates picture flaws. These images often look rather fuzzy and ill-defined. More satisfying is the Dolby Digital 5.1 soundtrack of ST IV . The forward soundstage is very broad but nicely spatial, with convincing imagery that places audio in specific spots but blends it together nicely. The surrounds aren't tremendously active, but they add to the experience with some effective backing, and we even hear some decent split surrounds on occasion.