Many museums, galleries, and archives assign a unique identification number or code to each artwork in their collections. These systems support collection oversight and research, and help institutions manage and track artworks. Identification and cataloguing systems ensure that every object, whether a painting, sculpture, or digital file, can be unambiguously referenced.
Unique Identifiers
Museums and galleries use and to uniquely identify artworks. When a piece is formally added—or “accessioned”—into a collection, it receives a number that typically encodes the year and sequence of acquisition. For example, the British Museum (London, United Kingdom) uses a format such as “1890,0511.1”. The first part might represent the date (11 May 1890) and the last number indicates that the artwork was the first item acquired that day. When an institution is responsible for keeping track of millions of objects, such a system is crucial. If a researcher inquires about a specific artifact, for example, museum staff can gather all records using that artifact’s number, and there will be no confusion with any other item. Accession numbering systems vary between institutions, and dates may be recorded or reflected differently depending on the system used.
Commercial galleries issuing usually include a serial or reference number on the certificate, often alongside a photograph of the artwork and the artist’s signature. This number might also be physically written on the artwork (on the back of a canvas, or on the base of a sculpture) or on an attached label.
When artworks are transferred or sold, these identification numbers help verify that the certificate or record matches the piece in question. In the digital era, some galleries integrate these IDs with blockchain or database systems so that scanning a QR code on the COA can instantly bring up the piece’s info online.
Catalogue Raisonné as an Identification Tool
A is a comprehensive, scholarly record of all works known to be created by a single artist. Such catalogues are typically prepared by qualified experts, foundations, art historians, or an artist’s estate, depending on the artist and local practice. A catalogue raisonné can be another important identification tool, particularly for art historians and authenticators.
Each artwork listed in a catalogue raisonné is usually given a unique reference, such as a number or code. This reference is accompanied by essential information including the work’s title, date of creation, materials or medium, dimensions, provenance, and exhibition history, along with relevant bibliographic references. High-quality images and scholarly essays may also be included.
Because a catalogue raisonné aims to list every legitimate work by an artist, owners of a painting or sculpture will seek to have the work they own included in the appropriate catalogue raisonné. If it is included, the catalogue will often serve as a source for verification (e.g., “this painting is #137 in the 2006 catalogue raisonné of Artist X”).
Given the authority that catalogues raisonnés carry, a mistake or omission can cast doubt on a work’s status. For this reason, the process of creating or updating a catalogue raisonné is rigorous, sometimes taking many years of research. While the catalogue itself does not constitute legal proof of authenticity, once published it is an invaluable reference for identification. Anyone can check if a purported work by Artist X appears in the catalogue, and if so, under what details.
Conversely, if a work is absent from a major artist’s catalogue raisonné, buyers will be cautious. New authentic works sometimes do surface, however, and they can get added to a catalogue raisonné via supplements or addenda. Absence is therefore not proof of forgery—but it can raise the need for extra authentication.
In recent years, efforts have been made to promote professional standards in the preparation of . For example, the International Catalogue Raisonné Association (ICRA) brings together scholars, foundations, and institutions involved in projects in order to encourage best practices, transparency, and scholarly exchange in this field.
For more information, explore our page on the Role of Catalogues Raisonnés.
Object ID
Various international standards have been designed to help identify and catalogue artworks across different organizations. One of the most widely adopted is the standard, which was developed in the 1990s by the Getty Information Institute (Los Angeles, United States) in collaboration with museum professionals and law enforcement institutions.
defines a checklist of core categories of information needed to identify a cultural object if it is stolen or missing. These include the type of object, the materials and techniques used to create the object, the object’s dimensions, any inscriptions or markings found on the object (such as signatures or foundry marks), and distinguishing features (damage, repairs, or unique traits), along with the object’s title or name, a description of the depicted subject matter, date or period, and maker/artist. Object ID criteria also include guidelines for photographing the object from multiple angles.
By recording this detailed identifying information, objects can be described in a standardized way.
If a sculpture is stolen and later intercepted, for example, authorities can compare an report to the item, verifying characteristics such as dimensions, material, and markings to confirm identity.
The Object ID standard has been translated into 17 languages and is widely used by police and customs agencies worldwide.
Institutional Coding Systems
Many large institutions also have their own in-house coding systems, often combining an acronym for the museum or archive with a unique number. The Smithsonian Institution (Washington, D.C., United States), for example, has released an open data set of its collection using such identifiers, allowing researchers to query information programmatically. Similar systems are used by major institutions worldwide, such as the Louvre Museum (Paris, France). Stable identifiers like these facilitate research, accurate citation, data sharing between institutions, and the reporting and tracing of lost or stolen works.
Metadata as Identification in the Digital Environment
Metadata plays an increasingly important role in identifying artworks in digital environments.
Metadata is structured information that is embedded in, or attached to, a digital file. This information may include the artist’s name, the title of the work, the work’s date of creation, the materials or technique utilized, and the work’s copyright status and licensing terms. Depending on the country, platform, or technology used, metadata may be automatically generated, or it may be manually added by the artist, and it may be modified during sharing and publication.
Metadata functions as a digital identity layer. It helps link an artwork to its creator, supports attribution and rights management, and enables artworks to be searched, tracked, and licensed online. However, metadata can be lost or altered when files are copied, compressed, or uploaded to certain platforms. For this reason, artists are increasingly encouraged to retain original files and keep separate records of key information.
Metadata information such as the author of the work, the owner of any right in the work, the rights attached to the work, applicable licensing terms, and any numbers or codes that represent such information, is often referred to as “rights management information”.
International copyright treaties require many countries to provide legal protection for rights management information. These treaties oblige countries to ensure adequate and effective remedies against the intentional removal or alteration of such information, as well as against the distribution of works where rights management information has been knowingly removed or altered. Depending on how these obligations are implemented nationally, remedies may be civil, criminal, or both.
Explore our page on Metadata Management to learn more.
In recent years, there has been growing interest in developing more universal and interoperable systems for identifying artworks. Various initiatives involving artists, galleries, auction houses, museums, cultural institutions, and technology providers are exploring ways to assign a single, persistent identifier to each artwork.
This would function similarly to the way in which international numbering systems identify books through identifiers such as ISBNs. In the publishing sector, such systems help ensure that contributors such as illustrators and cover artists are properly identified and credited.
Many of these models are still evolving, and their long-term governance, accessibility, and acceptance will depend on collaboration among artists, institutions, collective management organizations (CMOs) and market actors worldwide.
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