This work is in the public domain in the United States because it was published in the United States between 1929 and 1977, inclusive, without a copyright notice. For further explanation, see Commons:Hirtle chart as well as a detailed definition of "publication" for public art. 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 (50 p.m.a.), Mainland China (50 p.m.a., not Hong Kong or Macao), Germany (70 p.m.a.), Mexico (100 p.m.a.), Switzerland (70 p.m.a.), and other countries with individual treaties.
The photograph was included in Seeing the Unseen: Twelve Photographs by Harold Edgerton, a portfolio published in 1977. Museum and auction listings with descriptions and photographs of the portfolio show no trace of any copyright notice. Examples: [1][2][3][4][5]
It was published again in the portfolio Harold Edgerton: Ten Dye Transfer Photographs, 1985. Again, images of the portfolio show no copyright notice. Most clearly, this can be seen in a LA Modern auction listing showing the title page and colophon page. Other examples: [6][7][8][9][10][11][12]
Furthermore, copyright may have expired for lack of renewal even if all copies included proper copyright notice. Other prints of the photograph exist from 1963 and earlier, for example the print in the collection of the Museum of Modern Art. No relevant copyright renewal is found in the U.S. Copyright Catalog. It is not clear that these prints were ever published though.
Captions
''Milk Drop Coronet'', an ultra-high-speed photograph of the splash of a drop of milk.