Restoring a Masterwork II: Guercino's Erminia and the Shepherds
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The Restoration
Daily Log
Condition Report
What's Wrong?
Treatment Steps
IR and UV Photography
Anatomy of a Painting
The Painting
General Overview
Jerusalem Delivered
The Commission
The Artist
The Engraving
Painting and Engraving

Infrared and Ultraviolet

Infrared Reflectography

Infrared light penetrates deeper into the painting's structure than ultraviolet light. Photographs taken by means of infrared reflectography (IR) can show underdrawings beneath the topmost design layers; fills where the original paint and ground layers are lost; structural damage such as tears and holes; and changes that the artist made in the composition.

Ultraviolet Photographs

These photographs taken in ultraviolet (UV) illumination reveal the structure of the painting's surface layers. Ultraviolet light causes varnishes and retouching to fluoresce, and the specific manner and color of the fluorescence aids in identification. The greenish yellow overall coloration here indicates a natural resin varnish, such as mastic or dammar. The dark passages suggest restoration, broadly applied retouching, and overpainting.