The National Library of Israel has a collection of archives that include metric books, photographs, and documents from Chornyi Ostriv*.
*Documents in this collection are in Russian
Chornyi Ostriv is specifically mentioned in this record.
The Extraordinary State Commission to Investigate German-Fascist Crimes Committed on Soviet Territory from the USSR contains selected material about victims, crimes against persons, and perpetrators, and excludes information about crimes against property. Documents include victim name lists, protocols of interrogating eyewitnesses by local members of the Extraordinary Commission, and signed depositions summarizing the commission’s findings. Also included are photos, diagrams, and maps showing the location of atrocities and graves."
*This record is only accessible in person at the United States Holocaust Memorial Museum in Washington D.C..
Alexander Krakovsky is a Jewish-Ukrainian archivist, activist, and genealogist. He is a leader in the Jewish genealogical community in efforts to legalize the digitization of Jewish records from Ukrainian historical government archives.
The records that pertain to Chornyi Ostriv would be in the Archive: Jewish town/Podilskyi province-Proskurov
The website is in Ukrainian. After translation, look for "Black Island Jews" and "Chornoostriv". The records are all in Russian.
Learn your family’s surnames and given names in the Cyrillic alphabet, and determine how they could look in Russian cursive script. This is easier than it sounds: Steve Morse provides one-step tools to transliterate and to show cursive characters. Once you learn the shape of your family’s names, you can skim and search through images of untranslated, unindexed records. (Thank you to Sarah Millspaugh for this helpful reference; more can be found on the Dnipro Community Research page in section Advanced Strategies for Finding Records)