How we build the models

Each type page shows two linked 3D models: an as-minted reconstruction and a found specimen. Both are made from the front and back photographs of one recorded find.

What the photographs can and cannot tell us

A photograph shows the outline and the design clearly, but not depth. We estimate relief from light and shade in the photograph. That depth is inferred: it is not measured, and the models are not scans or replicas.

Size

Where the record gives a diameter, the model is that size. Where it does not, we measure the scale bar in the photograph; on the coins with recorded diameters this method came within about 3 to 8 per cent. Thickness is only measured on one coin; elsewhere it is worked out from the recorded weight and an assumed density for the broad metal, or set from the diameter where no weight is recorded. Labels on the model quote recorded figures only.

As minted

The as-minted model keeps the shape of the real flan and its hand-struck irregularities, removes corrosion and wear marks, and restores broken edges only where a break is recorded or plain to see. We never add letters or designs that the photograph does not show. If a face is too worn to show its design, we leave it plain and say so.

Evidence labels

• Observed in the photo: we can see it on the specimen photograph.
• From another specimen: taken from a different, licence-checked coin of the same type (none used yet).
• Inferred: our reconstruction, shown with the Inferred areas overlay.
• Record only: named in the find record but not visible, so not modelled.

As found

The found model uses the photographed outline, surface and colour of the real specimen. The slider between the two is an illustration: in-between states are not evidence of how the coin aged. Wear presets are illustrative flattening of the as-minted model, not grades.

Orientation of the two faces

We place the reverse relative to the obverse by matching the outlines of the two photographs. Where a record gives a die axis we check against it.

Tools

Models are built in Blender and shown with three.js (MIT licence).