In 2022 the State Museum and Exhibition Center ROSPHOTO received a cultural heritage object of significant interest—a wooden board with three children's portraits created in a rare photographic technique using gold powder. The performed analysis of the heritage object in combination with a detailed study using a set of complementary scientific methods allowed to clarify several blind spots related to this example of Japanese photographic art: the authorship; the period of time when the portraits were created and a number of technological aspects applied to the image during its production. The set of scientific methods, namely optical microscopy, X-ray fluorescence analysis, infrared spectroscopy and anatomical wood examination, was applied to the object in order to determine the content and technique of rare photographic image as well as to identify the wood type used as the base. It was found that the studied image was made via unique and rarely seen gold mizunotype technique and the portraits were created on the wooden board made of Chamaecyparis obtusa, also called Japanese cypress or Hinoki. To the best of our knowledge no detailed scientific and comprehensive study was performed for these XIX–XXth century Japanese photographic art relics. Such objects are one-of-a-kind exhibit, that is why the opportunity to come into contact with such artifacts is a huge success for all—art historians, curators and researchers.