Digital technology.

During the 1990s, digital sound, editing, photography, and special effects revolutionized movie making, creating the biggest change in how movies are made since the introduction of synchronized sound in 1927. The use of digital editing in Forrest Gump (1994) demonstrates the enormous strides made in motion-picture technology during the 1990s. Gary Sinise plays a character whose legs are blown off in battle. While in earlier movies an actor would have played his scenes with his lower legs taped behind his thighs, digital technology could remove Sinise's legs after the footage was shot. Moviemakers used a blue screen and 3-D digital technology — developed by George Lucas's Industrial Light and Magic, the special-effects division of LucasFilm — to create the illusion of a legless actor so successfully that viewers could not tell the scene was digitally enhanced. Also in Forrest Gump, director Robert...