Guest Author: ReMasterpieces: A Machine Learning Powered Provenance Research Tool

2018 marks the 20th anniversary of the global adoption of the Washington Conference Principles on Nazi-Confiscated Art. The Principles articulate 11 strategies countries can implement to resolve issues surrounding the identification and restitution of art stolen by the Nazi’s prior to and during World War II. Renewed interest in the Principles has prompted the convening of many conferences around the world to discuss progress and implementation of the strategies. As victims of Nazi persecution pass away each year, restitution efforts become increasingly difficult, leaving some claims potentially unresolvable.


Following calls by the American Alliance of Museums (AAM) and the International Council of Museums (ICOM) after the Washington Conference, museums around the globe searched their collections, many creating digital platforms documenting the provenance of their holdings. Provenance information from these projects, as well as data from the Getty Provenance Index, have contributed greatly to the effort to return cultural property to those who suffered at the hands of the Nazis.

This valuable work is not without limitations. Every year, stories emerge detailing how a painting or tapestry adorned the walls of a middle-class family home for decades only to discover the work was taken from a Nazi hideout by a soldier during World War II. Whether discovered in a museum or in a private home, any artwork with a questionable ownership trail should be investigated to ensure that the rightful owner ultimately has control over the piece.

This begs the question, how can museums use their digital provenance platforms to engage and empower patrons with tools to recognize stolen art in the world at large?  


ReMasterpieces seeks to provide a solution. ReMasterpieces is an academic research project created with two goals in mind: first, to recreate missing works of art using computer vision and machine learning and present the works to the original owners and second, to educate and empower people to find the actual missing works of art.

The general process of using ReMasterpieces to recreate missing works of art includes the following steps:

  1. Scrape the web to identify paintings that were allegedly stolen by the Nazis, photographed before the theft, and are still missing today

  2. Use computer vision (CV) and machine learning (ML) to:

    1. Enhance the quality of the photographs

    2. Add accurate color to the photographs

    3. Develop individual heightmaps to ensure accurate surface textures for each painting

  3. 3D print the paintings

  4. Display the works to educate the public

  5. Return the works to the original owners or their heirs

To date, this process has yielded the creation of one of the most iconic works of art missing since World War II: Raphael’s Portrait of a Young Man.

3 painting pic.jpg

Now, returning to empowering patrons to find missing art. Step one in the ReMasterpieces process produced a database of over 15,000 missing paintings that were photographed before their theft. This is a powerful database that most people would not access on their own to see if the painting hanging in their home or school was a missing work of art.

To aid in the search, ReMasterpieces is developing a web application and an API called ReMasterpieces Search that museums can implement into their own provenance platforms and apps allowing patrons to take pictures of any item in the world and see if it is in the database of missing art. If a match is found, the application will direct users to report the object to the appropriate authorities, who can then ensure the rightful owner ultimately has control over the piece. Future development could include searching the FBI National Stolen Art File and the INTERPOL Stolen Art database among other databases. ReMasterpieces aims to create a crowdsourced search-party for missing cultural property.

This technology contributes to the global effort to find missing art by realizing five of the Washington Conference Principles advocated by both AAM and ICOM:

  1. Art that had been confiscated by the Nazis and not subsequently restituted should be identified.

  2. Relevant records and archives should be open and accessible to researchers, in accordance with the guidelines of the International Council on Archives.

  3. Resources and personnel should be made available to facilitate the identification of all art that had been confiscated by the Nazis and not subsequently restituted.

  4. Every effort should be made to publicize art that is found to have been confiscated by the Nazis and not subsequently restituted in order to locate its pre-War owners or their heirs.

  5. Efforts should be made to establish a central registry of such information.

Finding missing art is about education, awareness, and accessibility. On the eve of the 20th anniversary of the Washington Conference Principles on Nazi-Confiscated Art and the 75th anniversary of the end of World War II in 2020, using technology such as Remasterpieces, we may all join the search to find missing works of art and aid in reuniting victims of Nazi persecution with their cultural heritage.

To learn more about the work of ReMasterpieces and how your museum can access the API, visit:

Authors Note:

If a work or art is identified as potentially missing or stolen contact the appropriate authorities. Do not attempt to address the situation by actions such as removing, defacing, or in any way harming the work, the location of the work, or the people connected with the work. Take note of the item’s appearance, location, and circumstance of discovery. Photograph the work if possible. Email if you need further assistance.

Look for more posts from guest writer Daniel Fonner throughout the year. View Daniel’s AMT Lab archive.