Gary Oldman wanted to wear elaborate prosthetic makeup to closely resemble the historical Herman J. Mankiewicz but was persuaded otherwise by David Fincher, who wanted minimal makeup for capturing a more intimate performance.
Mank (2020) has a monaural sound mix, similar to what films had before the stereophonic sound system was introduced in the mid-20th century. This means that instead of multiple soundtracks dedicated to dialogue, music, and other sound effects, all of the aforementioned were shared on one single track.
Shot on RED's Helium Monochrome 8K cameras, no color version of this film exists.
For most of December 2019, the film was shot at the Kemper Campbell Ranch in Victorville, California, where Herman J. Mankiewicz wrote Citizen Kane (1941). Considering the ranch changed very little over the years, the location helped reflect the time period of the late 1930s.