A polymeric film is often applied to tablets by subjecting them to an atomizer-produced spray while simultaneously tumbling them inside a rotating circular, perforated drum. The quality of the film coating has been found to depend upon the process operational parameters. This review focuses on how those parameters influence spray characteristics, and on how the spray characteristics in turn influence the quality of the film coat. Emphasis is placed on experimental results and analytical solutions that help identify factors that either improve coating quality or impair it. In particular, the available literature has demonstrated that much of the observed film "defects" can be explained by droplet wetting characteristics and by understanding how mechanical stresses are developed in film coatings. Inter-tablet (i.e., tablet-to-tablet) coating non-uniformities, on the other hand, likely arise from non-uniformities in the sprays. Issues to be addressed, and areas that require improvements, are also highlighted.