This image is in the public domain in Denmark because the DanishConsolidated Act on Copyright of 2010 specifies (§91, 5) that all photographic images not considered to be "photographic works" that were created before 1 January 1970 are exempt from protection (details).
Note that "photographic works", which must display artistic merit or originality, enter the public domain 70 years after the death of the photographer and that photographs that are not considered works but created 1 January 1970 or later become public domain 50 years after they were created. See Licensing for details.
Some countries have a lower threshold of originality and may therefore apply a longer protection term for this image, so it may not be usable in such countries.
To uploader: For this to be applicable, creation year must be known (or known to be at least before 1970)
You must also include a United States public domain tag to indicate why this work is in the public domain in the United States.
Public domain works must be out of copyright in both the United States and in the source country of the work in order to be hosted on the Commons. If the work is not a U.S. work, the file must have an additional copyright tag indicating the copyright status in the source country. Note: This tag should not be used for sound recordings.PD-1923Public domain in the United States//commons.wikimedia.org/wiki/File:Oluf_Nicolai_Olsen.jpg
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