What is PHOTARCH?

Uniform, measurable photographs of archaeological artefacts

Across archaeology and cultural heritage, photography remains one of the most widely used tools for documenting material culture.

Yet despite its ubiquity, there is still little visual standardisation in the way artefacts are photographed.

From excavation reports to museum databases, images are often produced under widely varying conditions — with inconsistent lighting, angles, backgrounds, scale references, and metadata.

While initiatives such as FADGI (2023) and Metamorfoze (2025) have established important standards for digitising books, manuscripts, and archival materials, their application to archaeological artefacts remains limited.

As a result, images of artefacts are often visually isolated: they document individual objects, but rarely support meaningful comparison across collections, institutions, or research contexts.

PHOTARCH offers a photographic method and a digital framework for documenting archaeological artefacts. The method is a few principles that, if you follow them, give uniform photographs that can be measured, again and again; images made this way work not only as illustrations, but as structured visual data.

By applying consistent imaging principles across collections, PHOTARCH seeks to create a coherent visual dataset of artefacts that supports long-term research, cross-collection comparison, and future computational analysis of cultural heritage.

A method grounded in practice

PHOTARCH is a photographic method, developed through fieldwork and collaboration with museums, researchers, and heritage institutions. It is not an imaging system you are asked to adopt in place of your own.

The method is free to follow with a camera, a lamp and a digital caliper, and the file format it writes is published openly so that any program may read or write it. Three pieces of software exist to save you doing it by hand: the PHOTARCH app, where a photograph is measured, validated and exported; PHOTARCH for iPhone, which sends photographs to the Mac as they are taken; and the archive at app.photarch.com, where an object can be published, compared at true scale and cited.

The method establishes a repeatable workflow for artefact photography based on six key principles.

Consistent lighting

A single key light at a fixed angle (typically 45°), with a weaker fill light opposite to soften the shadow, ensures consistent modelling of surface form and shadow.

White background

A pure white base allows clean separation of the object while preserving natural shadow depth and enabling histogram-based exposure control.

Named camera angles

Camera positions are named on a sphere rather than chosen from a list: F, Front, for the plumb view straight down and B, Back, for the underside — the two faces, like a coin; T and D for the top and down ends; L and R for the sides; and ATL, ATR, ADL and ADR, A as in angle, for the diagonals looking down at 45° at the corners. The object lies on the board and the camera moves round it; the lamp never moves. Each picture therefore carries both its position and the light that position gives.

Accurate colour management

ICC profiles and calibrated colour targets ensure reliable colour reproduction across different cameras and lighting conditions.

The record travels in the file

Every exported picture carries its own documentation: Dublin Core, IPTC and PHOTARCH's own fields as XMP, the measurement as Image Scale Metadata, and — under a paid licence — a signed C2PA manifest saying how the picture was made and what one pixel covers on the object. The file can be read, measured and trusted wherever it ends up, without asking the archive.

Open adaptability

The method is equipment-agnostic and scalable, and can be implemented using mirrorless, DSLR, or medium format camera systems.

How the method is carried

1. PHOTOGRAPH — white ground, key at 10:30, shadow kept; a card every sitting
2. MEASURE — the board's markers give mm per pixel: Image Scale Metadata
3. CHECK — what the picture is fit for: 4, 12 or 24 px per mm
4. HAND OVER — export or publish; record and seal go in the file

From photographs to visual data

The lack of consistency in artefact photography is not merely an aesthetic issue.

It affects the scientific usability of images.

Photographs that lack scale, show ambiguous colour information, or present objects from undocumented angles cannot be reliably compared or integrated across studies.

PHOTARCH approaches photographic documentation as data generation rather than illustration.

By producing images under controlled and repeatable conditions, the method creates visual records that can be compared directly across collections and time.

In the long term, PHOTARCH aims to contribute to the development of a machine-readable visual dataset for archaeological artefacts — a resource that could support visual comparison, large-scale studies of ornament and form, and future AI-assisted analysis of archaeological material.

The PHOTARCH reference dataset

Beyond a photographic method, PHOTARCH is developing a visual reference dataset for archaeological artefacts, every image in it made the same way. The long-term goal is to establish the first machine-readable image dataset of archaeological artefacts — a resource that could support:

• visual comparison between collections

• large-scale studies of ornament and form

• reproducible documentation of artefacts

• computational analysis of archaeological material

Because all images are produced under controlled and repeatable conditions, the PHOTARCH dataset has the potential to become a reference resource for researchers and digital heritage initiatives.

Proven in practice

PHOTARCH has been developed in collaboration with institutions including Lund University Historical Museum, Moesgaard Museum, and Kalmar County Museum.

More than 1,000 artefacts from Bronze Age, Iron Age, and Early Medieval contexts have been photographed using the method. That is the count of objects photographed by the method; the number published in the open archive is smaller and grows as institutions release their material.

The project received support from Fujifilm through the 2022 Challenge Grant.

The work has been presented internationally at conferences including the 2and3D Photography Conference at the Rijksmuseum and the European Association of Archaeologists Annual Meeting.

Images produced using the method have also appeared in publications including National Geographic, BBC, and The New York Times.

Interested in using the method?

PHOTARCH workshops and advisory sessions are offered for museums, researchers, and heritage institutions interested in following a consistent photographic method for artefact documentation.

Instructional videos and training resources are currently in development.

To stay informed about workshops, collaborations, and updates, please sign up for the newsletter.

References

• guidelineFADGI (2023). Technical Guidelines for Digitizing Cultural Heritage Materials, 3rd ed. Library of Congress.Four-star levels for flat and bound material. No chapter on three-dimensional objects.
• guidelineMetamorfoze (2025). Preservation Imaging Guidelines, version 2.0 (first edition 2012). KB / Nationaal Archief.The Dutch national preservation programme, for flat originals.
• standardISO 19264-1:2021. Imaging systems quality analysis — reflective originals.Measures the device against a test target, not the picture of an object.
• formatImage Scale Metadata (ISM) 0.1, draft specification.Open: specification under CC BY 4.0, reference library under MIT.