Colorizing is an editing technique which changes black and white images into color. Some studios have colorized old black and white films, to great controversy.
Colorization has existed since the birth of film, but it was a complicated hand-drawn method. Once color film stocks became cheap, hand coloring of movies disappeared altogether.
In 1977, Italian filmmaker Luigi Cozzi decided to release Godzilla (1954) to Italian cinemas; however, he was only able to get the shorter American cut and Italian cinemas refused to screen black and white movies back then. He decided to crudely colorize the film using gel on places (grassy areas would be green and, in a rather racist manner, large crowds of people would be yellow). This is the first instance of a black and white film being colorized for a re-release.
The First Wave of Controversy (1980s-early 1990s)
In 1983, Hal Roach Studios ventured into the colorization market using digital computers to do the work. The results attracted many TV executives, including media mogul Ted Turner, who wanted colorized films as a way to attract higher advertising revenue and to get younger people to watch old movies.
The process attracted lots of controversy from film fans and purists, including Roger Ebert, Orson Welles and George Lucas (who ironically altered his own movies in the 1990s) who saw it as cultural vandalism since those movies were filmed and lit for black and white film, ruining genres like film noir, plus the poor methods of colorization in the 1980s, which often led to "color bleeding". When Ted Turner joked about colorizing Citizen Kane, Orson Welles demanded, three weeks before his death, to "get Ted Turner and his damn Crayolas away from my movies". Luckily the colorization never went through.
The controversy led to the creation of the National Film Preservation Act and the National Film Registry.
In 1990, 1992, and 1995, Warner Bros. digitally colorized select Looney Tunes shorts. This proved less controversial than coloring live-action movies (and proved better than redrawing the cartoons in the Seven Arts era in the late 1960s), mainly because it was executed better by using computer software to color the shorts while preserving the original animation (while the 1990 and 1992 colorizations were still criticized for washed-out and poor color choices, 1995 colorizations were better received). Other examples include the colorization of certain Laurel and Hardy short subjects by Hal Roach Studios, as well as the computer-colorization of Disney's B&W Mickey Mouse cartoons in 1992.
The Second Wave of Controversy (2000s-Present)
In the 2000s, Sony Entertainment released colorized editions of movies from The Three Stooges. Again, controversy erupted, but this time on a smaller scale, as the technology had improved to allow better colorization as well as allowing both the color and black and white versions to appear on the same DVD. Some industry veterans like Shirley Temple and Ray Harryhausen assisted in the colorization of their movies.
In 2018, Peter Jackson released They Shall Not Grow Old, which featured colorized and digitally enhanced World War I footage. The film received critical acclaim for the technology as well as its approach to WW1, showing that colorizing historical footage is a lot less controversial than colorizing classic movies.