A structured approach to artefact photography
The PHOTARCH method is built upon a set of clear and repeatable principles designed to ensure visual consistency, scientific comparability, and long-term usability of archaeological imagery. Its goal is to make object photography replicable not only within a single institution or excavation, but across collections, countries, and decades.
While individual images may appear deceptively simple, each photograph produced under PHOTARCH follows a strict logic regarding lighting, angle, background, and metadata. This page outlines the core principles of the method and the recommended setup for implementation, whether in a museum environment or in the field.
1. Lighting: Controlled and Repeatable
Lighting is at the heart of PHOTARCH. A single fixed light source (key light) is placed at a 45° angle from the object’s side and above (If the object is placed in the centre of a clock face, the primary light source is positioned at 10:00), ensuring consistent modelling of shape and surface. A fill light or reflector is used on the opposing side to soften shadows without eliminating them.
The aim is not to create artistic mood, but to produce measurable, interpretable, and repeatable lighting conditions across sessions and objects. The 45° angle allows for standardised shadow geometry, supporting both visual inspection and potential automated shape recognition.
Where possible, the light source should be colour calibrated and spectrally neutral.
2. Camera Angle
In PHOTARCH, the hero shot — the top-down view — serves as the primary image for presenting the artefact in public databases. This zenithal perspective offers clarity, neutrality, and easy comparability. It’s the standardised overview, much like the default product photo of a sweater in an online shop.
But a single image rarely tells the whole story.
That’s where additional angles come in — including what we call the money shot: a carefully lit diagonal view that captures form, detail, and visual drama. These supplementary images offer depth and dimensionality, helping researchers and the public alike to better understand the artefact’s character.
To make these multi-angle views consistent and repeatable, PHOTARCH employs a spherical grid system. The artefact is imagined as being placed in the centre of a virtual globe. The camera is then positioned along fixed latitudinal bands (labelled A–L) and longitudinal slices (1–12), like hour markers on a clock.
This referencing system ensures that camera positions can be defined, repeated, and compared across objects and collections. It allows each image to be tagged by its angle of capture and supports:
– Structured visual documentation
– Multi-angle comparison
– AI-based classification
– Long-term reproducibility
In other words, while the hero shot gives us the overview, the spherical system gives us the framework for everything else — the angles, the context, and the capacity to see collections as interconnected wholes.
Most objects are photographed in top-down (zenith) view for the hero image, supplemented by cardinal (front, back, left, right) and diagonal angles when needed.
3. Background: Clean, White, Consistent
PHOTARCH recommends a pure white background (RGB 255,255,255) for all images. This background serves three primary functions:
- It allows easy detection of exposure clipping in the histogram
- It provides a neutral context for shadows, making them visible but not overpowering
- It avoids the need for cut-outs or digital cropping, preserving spatial grounding
Neutral grey backgrounds, often preferred in museum photography, pose challenges in exposure balancing and are frequently removed during editorial processing — a practice that eliminates valuable shadow information and detaches the object from any visual context.
White backgrounds streamline the post-processing pipeline and are ideal for multi-platform publishing.
4. Scale and Colour
PHOTARCH integrates scale and colour targets directly into the photographic workflow to ensure visual accuracy and reproducibility. However, these reference tools are intentionally excluded from the final hero image — the top-down view that represents the artefact in public-facing databases.
Instead, a separate image should accompany each set of images, clearly showing the scale and colour chart under identical lighting conditions. This reference image functions much like a technical specification page in online retail — essential, but not in the spotlight. It should be part of the image set, not part of the showcase.
Together, these tools ensure that each image is not merely a visual representation, but a measurable, comparable data point. They allow researchers and viewers alike to interpret artefacts with both scientific precision and visual clarity.
4.1 Rethinking Scale: Beyond the Ruler
There are numerous guidelines for how to best position a scale in relation to an artefact — but none of them are truly accurate. A physical scale bar, no matter how carefully placed, only confirms the size of the scale itself, not necessarily the artefact.
While physical scales are useful for establishing the z-axis and indicating general spatial relationships, they fall short when it comes to precise dimensional accuracy. The only reliable way to define the size of an artefact is to measure it directly, using a calibrated digital caliper with at least two decimals of precision.
These measurements should be embedded in the metadata associated with the image. Where database systems allow, a digital scale overlay can also be imposed on the image, visually communicating the artefact’s true size without relying solely on a manually placed ruler.
This shift — from analogue reference to embedded measurement — is key to treating the photograph not just as an illustration, but as a trustworthy data point.
