This is an audio-visual and cinematographic work, and 50 years have passed since the year of its creation (that is, the work was made before 1974)
This is an anonymous or pseudonymous work, and 50 years have passed since the year of its creation or publication (that is, the relevant action was done before 1974)
This is a work of the government and 50 years have passed since the date when the work was published or first made available to public (that is, the relevant action was done before 1974)
This is a work of applied art and 25 years have passed since the year of its creation (that is, the work was made before 1999)
This is another kind of work, and 50 years have passed since the year of the author's death or last-surviving author's death (that is, the death occurred before 1974)
You must also include a United States public domain tag to indicate why this work is in the public domain in the United States.
Note that this work might not be in the public domain in countries that do not apply the rule of the shorter term and have copyright terms longer than life of the author plus 50 years. In particular, Mexico is 100 years, Jamaica is 95 years, Colombia is 80 years, Guatemala and Samoa are 75 years, Switzerland and the United States are 70 years, and Venezuela is 60 years.