Terminology

A record says what an object is made of, what kind of thing it is, when it was made, how it was made and what state it is in. PHOTARCH stores each of these as a code from a controlled list, never as free text, and anchors every list in a vocabulary or a standard that institutions in other countries already use. That is what lets a record from one collection be searched, compared and combined with a record from another.

The codes belong to no language. CORRODED is shown as Corroded to an English reader and as Korroderad to a Swedish one, and further languages can be added without touching a single record. An organisation that has its own words for things can map them to PHOTARCH's terms, so its staff keep working in the language they are used to while the archive stays consistent.

From the field to the format

Each field takes its words from one list. Each list points to the vocabulary or standard it is anchored in. When a record leaves PHOTARCH, the codes travel with it, and in Linked Art they travel as links.

The Getty Art & Architecture Thesaurus

The Getty AAT is the shared vocabulary of museums, libraries and archives worldwide, maintained by the Getty Research Institute. Every term in PHOTARCH's lists for material, object type, period and technique is linked to an AAT concept where one exists: 55 links in all.

A link says one of two things. Equivalent means the two terms name the same concept; 52 of the links say that. Broader means PHOTARCH's term lies inside a wider AAT concept without being the same: a scraper is one kind of scrapers (finishing tools), and the Nordic Roman Iron Age and Vendel Period are periods the AAT knows only by their wider names. A broader link never claims more than it means. A term with no AAT concept, such as Other, stands on its own, at its own PHOTARCH address.

Every link was checked against the Getty's own data at vocab.getty.edu on 22 September 2026. For the Nordic periods, PeriodO, the gazetteer of dated periods, is the planned next anchor, because it can name a regional period exactly where the AAT can only name a wider one.

What a term holds

A term in PHOTARCH is more than a word. Each one is kept as a small record, so that what it means and where it comes from can always be checked:

Linked Art and the terms

Linked Art is a community model for describing cultural heritage as linked data, built on CIDOC-CRM, the reference model museums use for exchanging information (ISO 21127). PHOTARCH publishes every object's record as Linked Art, and the model shapes how PHOTARCH handles its terms in three ways.

Linked Art classifies with the Getty AAT. Its records do not say "this is a fibula" in words; they say the object is classified as an AAT concept, and the same goes for the kind of every name, identifier, text and dimension. PHOTARCH follows that pattern. An object's title is classified as AAT Primary Name (300404670), its inventory number as Accession Number (300312355), its description as Description (300435416), and its length, width, thickness and weight by the AAT terms for those dimensions, in millimetres and grams.

A term PHOTARCH defines is still a concept with an address. Where PHOTARCH's own term and the AAT's are the same, the term's Linked Art record says so with equivalent. Where the AAT's is wider, it says broader. A period is a special case: the AAT describes periods as concepts, not as spans of time, so a PHOTARCH period is a Linked Art Period with its own years, classified as its AAT term. PHOTARCH links to the shared vocabulary and never replaces it; a term the AAT does not have keeps its PHOTARCH address and is not forced onto the nearest AAT word.

Dates before the common era. Linked Art writes dates as ISO 8601 date-times. PHOTARCH stores historical years, in which there is no year 0, so a year before the common era moves by one: 793 BCE is written as the ISO year −0792. Linked Art's JSON schema checks dates against RFC 3339, which only covers the years 0000 to 9999, so a date before the common era is valid JSON-LD but fails that one check. PHOTARCH writes the true year rather than a date that would pass.

Condition and alterations are kept in the archive's records and in exports from the PHOTARCH app. They are not yet part of the Linked Art record.

Condition: one scale, defined

EN 16095, the European standard for recording the condition of movable cultural heritage, asks that any scale used to score a condition be defined where it is used. PHOTARCH uses one scale, in the archive and in the PHOTARCH app alike, and defines each step:

The definitions are PHOTARCH's own. The standard requires that a scale be defined; it does not prescribe one.

Alterations: the terms of CEN/TS 17135

A condition step says how bad; it does not say what is wrong. For that PHOTARCH uses the terms of CEN/TS 17135:2021, General terms for describing the alterations of objects, the European vocabulary conservators use in condition reports. It builds on EN 15898:2019, the main general terms of conservation, and both are meant to be used together with EN 16095.

An object can carry as many alterations as apply. Each is stored by its code and keeps the clause number it has in the specification, so that anyone can look up exactly what the term means. The definitions themselves are CEN's text and are read in the specification; PHOTARCH carries the names only.

The general terms of §3.1 (alteration, damage, deterioration, object) define the words used in the rest of the specification. They are not something one sees on an object, so they are not in the list.

European, and published in every member country

The conservation standards are written by CEN/TC 346, the committee of the European Committee for Standardization for the conservation of cultural heritage. Each member country publishes them unchanged as its own national standard: as DIN EN in Germany, BS EN in the United Kingdom, NF EN in France and SS-EN in Sweden. A museum in Munich that follows DIN EN 16095 follows the same text as one in Lund that follows SS-EN 16095. CEN/TS 17135 is published in English, French and German.

At world level, ISO/TC 349 Cultural heritage conservation was formed in 2025. Read with the Getty AAT, which is used far beyond Europe, the lists described here are international from the start, and a national edition of a standard changes nothing in them. The page on the European conservation standards goes through what those standards ask of a photograph, clause by clause.

How the terms travel

The Metadata page describes the fields of a record in full.

References · Terminology

• vocabularyGetty Research Institute. Art & Architecture Thesaurus. Linked data at vocab.getty.edu.Material, object type, period and technique; every link checked on 22 September 2026.
• specificationLinked Art. Linked Art Data Model, and its context linked-art.json.Classification with the Getty AAT; Type, Material and Period; equivalent and broader.
• standardISO 8601-1:2019. Date and time — Representations for information interchange · RFC 3339. Date and Time on the Internet: Timestamps.Years before the common era, and the range RFC 3339 covers.
• committeeCEN/TC 346 Conservation of cultural heritage · ISO/TC 349 Cultural heritage conservation.
• vocabularyPeriodO, a gazetteer of scholarly definitions of historical, art-historical and archaeological periods.
• standardCEN/TS 17135:2021. Conservation of cultural heritage — General terms for describing the alterations of objects. CEN/TC 346.§3.2–3.8, the alteration terms.
• standardEN 15898:2019. Conservation of cultural heritage — Main general terms and definitions. CEN/TC 346.
• standardEN 16095:2012. Conservation of cultural property — Condition recording for movable cultural heritage. CEN/TC 346.A scale used to score condition is defined where it is used.
• standardISO 21127:2023. Information and documentation — A reference ontology for the interchange of cultural heritage information (CIDOC CRM).
• specificationLinked Art · LIDO · Europeana Data Model · DCMI Metadata Terms.