MIE — Multispectral Imaging Explorer

MIE is a browser-based, modular environment for preparing, processing, aligning and interactively exploring multispectral and documentary imaging datasets in archaeology and heritage science. Its four connected modules — Process, Align, Edit and Export — support a workflow from image enhancement and registration to the creation and dissemination of interactive multilayer Viewers. Projects can be saved locally and reopened for further work.

The Process module provides tools to prepare and optimise images for multispectral exploration, including adjustments to light, colour, tonal levels and individual channels, as well as reference-based colour correction for visible-light photographs. Exploratory enhancements — including chromatic separation, colour decorrelation, principal component analysis and false-colour compositions — can increase the legibility of faded or low-contrast decoration, bring out subtle traces and accentuate differences in the response of colours and materials. These operations support visual examination and the formulation of hypotheses; they do not, on their own, establish material identifications.

Across wall paintings, easel paintings, manuscripts, polychrome objects and other works of cultural heritage, the combination of different imaging layers can reveal features difficult to distinguish in visible light and help map variations associated with materials, execution techniques and later interventions. Visible-induced luminescence (VIL) can highlight Egyptian blue; UV-induced fluorescence (UVF) can reveal differences in surface coatings, certain binders and other materials, as well as retouching and past restorations. UV reflectance (UVR) can enhance the contrast of faded paints and inks and help distinguish some pigments, retouches and surface alterations. Infrared reflectance (IRR) can reveal preparatory drawings, compositional changes (pentimenti), retouching and, under suitable conditions, details obscured by overlying paint, darkened or carbonised surface deposits. The visibility of these features depends on the materials, their stratigraphy and the imaging conditions. MIE also brings these images together with historical photographs, drawings and digital reconstructions in a common spatial framework, supporting the study of making techniques and the development and visual assessment of virtual reconstructions.

Alongside its research applications, MIE is also intended as a tool for teaching and dissemination. Interactive comparison tools such as the slider and spotlight make differences between imaging layers immediately visible, allowing students and non-specialist audiences to explore information that may otherwise be difficult to perceive or interpret. Its accessible interactive Viewers can also be used in museums and exhibitions to present scientific images and interpretations directly to visitors.