This work is in the public domain because it was published in the United States between 1931 and 1963, and although there may or may not have been a copyright notice, the copyright was not renewed. For further explanation, see Commons:Hirtle chart and the copyright renewal logs. Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (70 years p.m.a.), Mainland China (50 years p.m.a., not Hong Kong or Macao), Germany (70 years p.m.a.), Mexico (100 years p.m.a.), Switzerland (70 years p.m.a.), and other countries with individual treaties. العربية ∙ Deutsch ∙ English ∙ español ∙ français ∙ galego ∙ italiano ∙ 日本語 ∙ 한국어 ∙ македонски ∙ português ∙ português do Brasil ∙ русский ∙ sicilianu ∙ slovenščina ∙ українська ∙ 简体中文 ∙ 繁體中文 ∙ +/−

Nancy Wolff, includes a similar explanation:

"There is a vast body of photographs, including but not limited to publicity stills, that have no notice as to who may have created them." (The Professional Photographer's Legal Handbook By Nancy E. Wolff, Allworth Communications, 2007, p. 55.)

Film industry author Gerald Mast, in Film Study and the Copyright Law (1989) p. 87, writes:

"According to the old copyright act, such production stills were not automatically copyrighted as part of the film and required separate copyrights as photographic stills. The new copyright act similarly excludes the production still from automatic copyright but gives the film's copyright owner a five-year period in which to copyright the stills. Most studios have never bothered to copyright these stills because they were happy to see them pass into the public domain, to be used by as many people in as many publications as possible."