Medical Technology & 3D Imaging in Mosaic Conservation

The Pammakaristos Mosaic Icon

Authors: Stefania Chlouveraki & Dimitrios Makris
Institution: University of West Attica (UNIWA)

The 12th-century Pammakaristos Mosaic Icon Byzantine mosaic icons are among the rarest treasures of world cultural heritage, with only around 50 surviving examples known globally. This study details the non-invasive investigation of the early 12th-century Pammakaristos icon (92 x 62 cm), housed at the Patriarchal Church of St. George in Istanbul.

Crafted from minute stone, glass, and gold-leaf tiles set into a delicate mixture of beeswax and natural resin, the icon represents a peak of Middle Byzantine luxury art. Because it is a living, miracle-working ceremonial artwork, centuries of continuous handling, religious litanies, and severe moisture fluctuations caused critical physical damage, loose tiles, and deep cracks in its wooden support.

By combining high-precision dual-energy Computed Tomography (CT-Scan), optical 3D laser scanning, and structure-from-motion photogrammetry, conservators mapped the artifact's structural damage and internal condition down to 0.6 mm section depth. This non-invasive documentation revealed crucial insights about past restorations and paved the way for safe, modern conservation without risking the sacred artwork.

Key Scientific Discoveries

1. Hidden Masterpiece Revealed

CT coronal sections revealed a hidden painted image of The Crucifixion on the back of the original wooden panel, making it a rare double-sided artwork.

2. Precision Nail Mapping

Radiographs and 3D rendering successfully mapped 221 corroded iron nails added over centuries, enabling safe, surgical extraction.

3. Sub-Millimeter Micro-Relief

3D laser scanning documented surface warping, gaps, and mosaic bulging caused by the aging of the beeswax-rosin bedding mortar.

4. Processional Handle Socket

A carved socket discovered at the base confirms the icon was carried in religious parades, explaining specific patterns of physical wear.

About the Artwork

  • Rare Byzantine Category: One of only 11 large-scale portable mosaic icons known to survive from the entire Byzantine period.
  • Iconography: Depicts the Virgin Mary holding the infant Christ, with Archangel Gabriel featured in a minute medallion at the upper right corner.
  • Physical Materials: Crafted from microscopic stone, colored glass, and gold leaf tiles set into a beeswax and tree resin paste.

Past Restorations & Damage History

  • Votive Cover Impact: Until 1933, heavy silver revetments were nailed directly onto the surface, leaving widespread nail damage around the figures.
  • 1933 Intervention: Empty mosaic areas were filled with plaster, and original details were obscured by heavy overpainting.
  • Secondary Support Panel: A backing board was attached long ago to structurally stabilize the split and insect-damaged primary timber.

Stefania Chlouveraki

Stefania Chlouveraki Stefania Chlouveraki is an Associate Professor in the Department of Conservation of Antiquities and Works of Art at the University of West Attica (UNIWA). She holds a PhD from the Institute of Archaeology at University College London (UCL) and served as Head Conservator at the INSTAP Study Center for East Crete from 1997 to 2014. An internationally recognized expert in Byzantine and archaeological mosaic restoration, Dr. Chlouveraki has directed landmark conservation, research, and field-training initiatives across Greece, Cyprus, Jordan, Syria, and Constantinople (Istanbul). Since 1993, she has led key heritage preservation programs for the European Centre for Byzantine and Post-Byzantine Monuments, collaborating closely with prestigious international research bodies.

Most notably, she spearheaded the landmark non-invasive conservation and diagnostic study of the 12th-century Pammakaristos Mosaic Icon at the Ecumenical Patriarchate of Constantinople. By combining advanced medical CT scanning, 3D laser scanning, and photogrammetry, her work mapped the icon's complex structural decay, 221 internal nails, and uncovered the hidden medieval painting of The Crucifixion preserved beneath its backing panel. Her primary research focuses on non-invasive 3D digital diagnostics for rare Byzantine mosaic icons, decorative architectural stone stabilization, and the engineering of innovative lightweight mounting systems for detached mosaics. Active in global leadership, she currently serves as Vice President of the International Committee for the Conservation of Mosaics (ICCM).

Ecumenical Patriarchate