National Association of Theatre Owners—cinema owner's body that sets exhibition standards for projection and sound. DCI and Dolby specs flow from their requirements.
NATO
NATO — the National Association of Theatre Owners — influences every mastering process we will see in cinemas, even though most filmmakers never meet them personally. This American association enforces the technical standards that cinemas worldwide must adhere to. Specifically, this means: anyone distributing their material for cinema is ultimately working against the standards defined by NATO. DCI projection, Dolby Atmos, color space specifications — these are not recommendations, but requirements that determine compatibility.
On set, we experience this less directly than later in color grading and sound design. However, it is worthwhile to keep NATO requirements in mind already during shooting. A DCI-compliant resolution (4K at 17:9, not 16:9) determines how we utilize the image framing. Sound guidelines — such as the level standards for Dolby or Atmos spatialization — influence how a sound designer sets up the mix suite. When preparing one's final color and sound lock, it's not the first time one encounters NATO specifications.
In practice, this means: The DCP (Digital Cinema Package) that we send to cinemas with the distributor must be built according to NATO standards. This affects not only the codec choice or metadata, but also which color space transformations we allow in the master. A colorist will tell you: the monitor must be calibrated, but not to arbitrary standards — to those of NATO. Mastering for cinema follows different rules than for streaming, and the cinema rules originate from there.
What's interesting is that while NATO standards originate from America, they are globally valid. A German cinema will have the same DCI projector as a multiplex in Tokyo. This creates planning certainty, but also forces us not to experiment independently — or to consciously work against the norm, which brings complications. Those who understand that NATO defines the infrastructure make better decisions during mastering.