1.1 Cover of the catalogue, An Exhibition of Cleaned Pictures, 1936–1947 (London: National Gallery, 1947). © The National Gallery, London 27
1.2 Photograph of the opening of the first General Biennial Conference in ICOM News, 1, no. 1 (1 October 1948). © ICOM Archives 30
1.3 IIC, Certificate of Incorporation (1950). © IIC 39
2.1 Restoration of paintings at the Central Laboratory of the Museums of Belgium (ACL) (ca. 1950). Photograph. CC BY. © KIK-IRPA, Brussels, 11047720 69
2.2 From left to right: Paul Coremans, Frans van Molle (assistant of Coremans), and Sheldon Keck at the Conservation Center of the New York Institute of Fine Arts (1963). Photograph. CC BY. © KIK-IRPA, Brussels, 11008945 69
2.3 Paul Philippot at the 1st Latin-American Regional Seminar for Conservation and Restoration, November 1973. Photograph by Claudio Sandoval. CC BY-NC. © Secretaria de Cultura.-INAH.-Mediateca.-Mex. Reproducción Autorizada por el Instituto Nacional de Antropologia e Historia, Mexico 72
3.1 Thomas Brachert with pupils, making a stucco marble inlay (1970/71). Photograph. © SIK-ISEA, Zurich 94
3.2 Copying in the Germanisches Nationalmuseum (1977). © Brachert Archive 96
3.3 National Gallery Cleaned Pictures exhibition pamphlet cover (1947). © The National Gallery, London 98
3.4 Ironing a wax-lining. Drawing by Kurt Mannig (undated). Archive of Michael von der Goltz. © The author 107
3.5 Restaurierung Moderner Kunst (Restoration of Modern Art). Dusseldorf Symposium 1977. © Restaurierungszentrum Dusseldorf 110
4.1 Eleanor McMillan, photographed in 1965. © Smithsonian Institution Archives. Image #OPA-1086 128
4.2a–b Charles Olin and Senator Joseph Montoya of New Mexico examining a stone sample from the Temple of Dendur. Above: © Smithsonian Institution Archives. Image MAH-P65868-02. Below: © Smithsonian Institution Archives. Image MAH-P65868-07 129
4.3 Robert Organ in 1974. © Smithsonian Institution Archives. Image #94-13196 132
4.4 Illustration from Tim Padfield’s “The Problem of Teaching Science to Conservators,” describing the many areas of knowledge conservators would be trained in, as compared to a more traditional scientist specializing in a narrow topic. © Smithsonian Institution Archives. Image #SIA2024-012795 145
6.1 Conservator Harald Brun in his studio (unknown date). © Nasjonalmuseet 185
6.2 Gothic sculpture controversy. University chemists, Dr. Botolfsen (left) and Dr. Holwech (right) (Oslo Aftenavis, nr. 102, Monday 4th May 1925). © Nasjonalbiblioteket 186
6.3 Edvard Munch, The Scream (1893). Tempera, casein crayon and oil on unprimed cardboard. © Børre Høstland/Nasjonalmuseet, NG.M.00939, 2024 189
6.4 Early hand-coloured cross-sections from NG’s conservation studio notebook. © Nasjonalmuseet 192
6.5 Example of an early NG condition/treatment report. Inger in Black & Violet. © Nasjonalmuseet, NG.M.00499 193
6.6 Conservator Leif Plahter examining a panel painting with NG’s first Zeiss microscope (1958). © Unn Plahter 195
6.7 Hovland stave church crucifix, Leif Plahter (left) and Martin Blindheim (right) (1959). © Unn Plahter 197
6.8 Leif and Unn Plahter working together on a polychrome sculpture (1967). © Nasjonalmuseet 200
6.9 Lab training for conservators from NG, Riksantikvaren and university museums. Left to right: Egil Dahlin, Arne Bakken, Erling Skaug, Svein Wiik, Truls Magnus Løkken, Mette Bjerke, Jon Andresen, Lars Kristian Hauglid, Turid Wilson (Kaland’s sister), Rolf Johansen, Bjørn Dammann, Janne Wang (Bakken) and Unn Plahter (1967). © Unn Plahter 201
6.10 Theodor (Dirck) van Baburen, The young Christ among the doctors (1622). Oil on unlined canvas. © Børre Høstland/Nasjonalmuseet, NG.M.00109, 2018 203
6.11 Cross-section of paint fragment from Baburen painting with large lumps captured in the ground layer (UV, magnification, X 137.5) (1983). © Unn Plahter 204
6.12 Left: X-ray powder diffraction patterns of the cadmium yellow samples taken from two versions of The Scream (1974). © Unn Plahter. Right: details of sample locations (after 2000). © Nasjonalmuseet 205
7.1 Quarta Mostra di restauro (4th Restoration Exhibition) (Naples: Palazzo Reale, November-December 1960). © Museo e Real Bosco di Capodimonte”. Su concessione del Ministero della Cultura – Museo e Real Bosco di Capodimonte. Reproduction not permitted 220
7.2 Simone Martini, Coronation of Robert of Anjou, from the Catalogue of the 4th Restoration Exhibition, front and reverse after restoration by Leonetto Tintori (1959). © 4. Mostra di restauri : catalogo. (Napoli: L’arte tipografica, 1960) 223
7.3 Titian, Portrait of Paul III bareheaded, from the Catalogue of the 4th Restoration Exhibition, the painting after restoration by Leonetto Tintori (1960), and detail taken during the cleaning. © 4. Mostra di restauri : catalogo. (Napoli : L’arte tipografica, 1960) 226
7.4 Masaccio, Crucifixion, from the Catalogue of the 4th Restoration Exhibition before and after restoration by Leonetto Tintori (1956–57). © 4. Mostra di restauri : catalogo. (Napoli : L’arte tipografica, 1960) 227
7.5 Masaccio, Crucifixion, detail of Mary Magdalene. © Museo e Real Bosco di Capodimonte”. Su concessione del Ministero della Cultura – Museo e Real Bosco di Capodimonte. Reproduction not permitted 228
7.6 Gabinetto Pinacologico (Cabinet of Pinacology), ‘radioscopy room’. Naples, Museo Nazionale (1932). © Su concessione del Ministero della Cultura – Archivio fotografico della Direzione regionale Musei Campania 229
7.7 Cover of Studies in Conservation, v. 4, no. 3 (Aug. 1959), the image is taken from Augusti’s article on the Capodimonte Conservation Laboratory, showing the booth for disinfesting wood by fumigation. © Augusti, Selim. “Front Matter.” Studies in Conservation 4, no. 3 (1959): i–ii. http://www.jstor.org/stable/1505066 232
7.8 Plan of the Restoration Laboratory on the second floor of the Museo di Capodimonte, taken from Augusti’s article in Studies in Conservation, here accompanied by the corresponding images. © Augusti, Selim. “Conservation Studios and Laboratories 1: The Conservation Laboratory of the Museo e Gallerie Nazionali di Capodimonte, Naples.” Studies in Conservation 4, no. 3 (1959): 88–95. https://doi.org/10.2307/1505069 233
7.9 Plan of the Scientific Laboratories located on the third floor of the Museo di Capodimonte, taken from Augusti’s article in Studies in Conservation, accompanied here by the corresponding images. © Augusti, Selim. “Conservation Studios and Laboratories 1: The Conservation Laboratory of the Museo e Gallerie Nazionali di Capodimonte, Naples.” Studies in Conservation 4, no. 3 (1959): 88–95. https://doi.org/10.2307/1505069 234
7.10 Copy after Diego Velázquez, The Drinkers, after restoration in 2004–2005: a) whole; b) detail in raking light; c) cross-section, showing the pinkish preparatory layer; d) cross-section in UV light, showing the paper fibres above the preparatory layer in an oil medium; e), f) microphotographs showing the paper fibres. © Su concessione del Ministero della Cultura – Museo e Real Bosco di Capodimonte 243
7.11 Sandro Botticelli, Madonna and Child with Angels, detail in UV and reflected light, from the Catalogue of the 4th Restoration Exhibition, during and after restoration by Edo Masini (1957). © 4. Mostra di restauri : catalogo. (Napoli : L’arte tipografica, 1960) 245
7.12 Masaccio, Crucifixion, detail in raking light and in reflected light, from the Catalogue of the 4th Restoration Exhibition, before and after restoration by Leonetto Tintori (1956–57). © 4. Mostra di restauri : catalogo. (Napoli : L’arte tipografica, 1960) 245
7.13 Giovanni Bellini, Transfiguration, a) whole, current photo. Details from the Catalogue of the 4th Restoration Exhibition: b) radiographic image; c) photo in reflected light after restoration by Edo Masini (1959–60). © Su concessione del Ministero della Cultura – Museo e Real Bosco di Capodimonte 248
7.14 Raphael and Evangelista of Piandimeleto, Eternal Father and Virgin, fragments from the Coronation of St. Nicholas of Tolentino, from the Catalogue of the 4th Restoration Exhibition, before and after restoration by Leonetto Tintori (1957). © 4. Mostra di restauri: catalogo. (Napoli: L’arte tipografica, 1960) 252
7.15 Raphael and Evangelista of Piandimeleto, Eternal Father and Virgin, fragments from the Coronation of St. Nicholas of Tolentino, before and after restoration by Francesco Virnicchi (1995). © Su concessione del Ministero della Cultura – Museo e Real Bosco di Capodimonte 252
8.1a–b Two views of Anthony Werner’s laboratory, photographed in 1949. © The National Gallery, London. All rights reserved 262
8.2 Brass Leitz’s microscope dating from 1896. Image from the 1940s. © The National Gallery, London. All rights reserved 270
8.3 Storage and chemical analysis of paint samples and cross-sections in the 1960s. Photographed for an exhibition held during April 1968, for Museums Week (1–8 April). © The National Gallery, London. All rights reserved 271
8.4 Pye Panchromatograph gas chromatograph purchased in early 1963. Photographed for an exhibition held during April 1968, for Museums Week (1 – 8 April). © The National Gallery, London. All rights reserved 274
8.5 The Milliprobe X-ray fluorescence analyser developed at the Oxford Research Laboratory for Archaeology and the History of Art. Photographed for an exhibition held during April 1968, for Museums Week (1–8 April). © The National Gallery, London. All rights reserved 277
8.6 The Chemistry laboratory in the newly opened Scientific Department. Photograph (1975). © The National Gallery, London. All rights reserved 278
8.7 The Zeiss Laser Microspectral Analyser. Photograph (about 1977). © The National Gallery, London. All rights reserved 282
8.8 Comparison microscope fitted with MPV photomultiplier used for transmittance microspectrophotometry of lake pigment dyestuffs. Photograph (1971). © The National Gallery, London. All rights reserved 284
10.1 Italian, Portrait Group. Panel. London, National Gallery (early 20th century). Published as “School of Melozzo” in the 1929 National Gallery Catalogue (b/w reproduction, 1920s: HAMA, Forbes Papers, box 37, f.2251, « Witt, Sir Robert »). © The National Gallery, London. NG3831 327
10.2 Italian, Portrait Group. Panel. London, National Gallery (early 20th century). Cross-section X-ray with paint film below, showing the adjacent radiopaque response of stucco (National Gallery of London, Research Centre, Curatorial Dossier). © The National Gallery, London. NG3831 328
10.3 Italian, Portrait Group. Panel. London, National Gallery (early 20th century). X-ray (National Gallery of London, Research Centre, Curatorial Dossier). © The National Gallery, London. NG3831 329
10.4 Equipment for stereo-strato-radiography, designed by Augusto Vermehren, at the Istituto Centrale del Restauro (from Bollettino dell’Istituto Centrale del Restauro 11–12, 1952, 132). © Istituto Centrale per il Restauro 335
10.5 Piero della Francesca, Flagellazione. Panel. Urbino, Palazzo Ducale, Galleria Nazionale delle Marche. Before restoration 1953 (ICR). © Istituto Centrale per il Restauro 340
10.6 Piero della Francesca, Flagellazione. Panel. Urbino, Palazzo Ducale, Galleria Nazionale delle Marche. X-ray with fixed source (ICR). © Istituto Centrale per il Restauro 341
10.7 Piero della Francesca, Flagellazione. Panel. Urbino, Palazzo Ducale, Galleria Nazionale delle Marche. X-ray with moving source (ICR). © Istituto Centrale per il Restauro 342
10.8 Rembrandt van Rijn, Aristotle with a bust of Homer. Canvas. New York, Metropolitan Museum. https://www.metmuseum.org/it/art/collection/search/437394 – Public domain 350
10.9 Rembrandt van Rijn, Aristotle with a bust of Homer. Canvas. New York, Metropolitan Museum. VIII autoradiograph showing the distribution of phosphorous (bone black) in the darkest areas. First published by M.W. Ainsworth, E. Haverkamp-Begemann, J. Brealey and P. Meyers, with contributions by K. Groen, M.J. Cotter, L. van Zelst, and E.V. Sayre. Art and Autoradiography: Insights into the Genesis of Paintings by Rembrandt, Van Dyck and Vermeer. (New York: The Metropolitan Museum of Art, 1982), 56 351
10.10 Rembrandt van Rijn, Aristotle with a bust of Homer. Canvas. New York, Metropolitan Museum. VI autoradiograph showing the distribution of arsenic (smalt) in the darkest areas. https://www.metmuseum.org/art/metpublications/Art_and_Autoradiography_Insights_into_the_Genesis_of_Paintings_by_Rembrandt_Van_Dyck_and_Vermeer 352
10.11 Rembrandt van Rijn, Aristotle with a bust of Homer. Canvas. New York, Metropolitan Museum. XRF imaging, showing the distribution of cobalt (smalt) in the lightest areas. Cobalt distribution map acquired by XRF imaging. D. Mahon, S.A. Centeno, M.T. Wypyski, G. van der Snickt, J. Dik and K. Janssens. “Rembrandt’s Aristotle with a Bust of Homer revisited: technical examination and new insights.” In Rembrandt Now: Technical Practice, Conservation and Research, eds. Marika Spring and Ashok Roy (London: Achetype Publications and the National Gallery of Art, 2022), 52–62 353
10.12 Rembrandt van Rijn, Aristotle with a bust of Homer. Canvas. New York, Metropolitan Museum. XRF imaging, showing the distribution of calcium (bone black) in the lightest areas. Calcium distribution map acquired by XRF imaging. D. Mahon, S.A. Centeno, M.T. Wypyski, G. van der Snickt, J. Dik and K. Janssens. “Rembrandt’s Aristotle with a Bust of Homer revisited: technical examination and new insights.” In Rembrandt Now: Technical Practice, Conservation and Research, eds. Marika Spring and Ashok Roy (London: Achetype Publications and the National Gallery of Art, 2022), 52–62 354
10.13 XRF scanner in front of Caravaggio’s Seven Acts of Mercy. Photograph by Marco Cardinali. Pio Monte della Misericordia (Napoli). © The author 356
11.1 J.R.J. van Asperen de Boer, studying the infrared image from the wings of a triptych by Pieter Coecke in Aschaffenburg. Photograph by Peter van den Brink. RKD, The Hague. © Peter van den Brink 366
11.2 Infrared reflectogram assembly, from a detail of The Good Samaritan Master, The Good Samaritan, Rijksmuseum Amsterdam. The inscriptions at the bottom left and center are instructions for its reproduction in Van Asperen de Boer’s chapter “An introduction to the scientific examination of paintings” in the Nederlands Kunsthistorisch Jaarboek 1975, p. 11 (as fig. 3c). The inscription at the lower right lists the archival numbers of the 35 mm film and individual negatives (IRR: J.R.J. van Asperen de Boer). Photograph by Ron Spronk. RKD, The Hague. © The author 367
11.3 The Barnes Infrared Camera. Plate III from: J.R.J van Asperen de Boer’s 1970 dissertation Infrared Reflectography; a contribution to the examination of earlier European paintings. Photograph by J.R.J. van Asperen de Boer. RKD, The Hague. © J.R.J. van Asperen de Boer 371
11.4a–c Illustrations from J.R.J. van Asperen de Boer, “Infrared Reflectograms of Panel Paintings”, in Studies in Conservation 11 (1966), no. 1, p. 46. Photographs by J.R.J. van Asperen de Boer. © IIC, Studies in Conservation 372
11.4d Workshop of Pieter Coecke, The Adoration of the Magi, Rijksmuseum Amsterdam. Detail of the triptych’s central panel. © Rijksmuseum, Amsterdam 372
11.5 Prof. J.R.J. van Asperen de Boer with student Geraldine van Heemstra studying the Norfolk Triptych at Museum Boijmans Van Beuningen, 1989. Photographer unknown. RKD, The Hague 377
12.1 Nam June Paik, Klavier Intégral (1958–1963). Collection mumok – Museum moderner Kunst Stiftung Ludwig Wien, formerly Sammlung Hahn, Cologne. © Estate of Nam June Paik. Photograph © mumok – Museum moderner Kunst Stiftung Ludwig Wien 396
12.2 Nam June Paik, Zen for Walking (1961). Collection mumok – Museum moderner Kunst Stiftung Ludwig Wien, formerly Sammlung Hahn, Cologne. © Estate of Nam June Paik. Photograph © mumok – Museum moderner Kunst Stiftung Ludwig Wien 398
12.3 Nam June Paik, Zen for TV (1963–1975). Collection mumok – Museum moderner Kunst Stiftung Ludwig Wien, formerly Sammlung Hahn, Cologne. © Estate of Nam June Paik. Photograph © mumok – Museum moderner Kunst Stiftung Ludwig Wien 399
12.4 Nam June Paik in Hahn’s house, around 1975. Archive mumok – Museum moderner Kunst Stiftung Ludwig Wien, formerly Sammlung Hahn, Cologne, inventory number: ARH-WH 192/0. Photograph © mumok – Museum moderner Kunst Stiftung Ludwig Wien 400
12.5 Lawrence Weiner, A Square Removal from a Rug in Use (1969), Collection mumok – Museum moderner Kunst Stiftung Ludwig Wien, formerly Sammlung Hahn, Cologne. © 2025, ProLitteris, Zurich. Photograph © mumok – Museum moderner Kunst Stiftung Ludwig Wien 407
13.1 Artist Zount creating a metal work. Photograph by Zount. Porto-Novo (2023). © Zount 427
13.2 Composition Aizinlili + djê (peanut paste and salt), 2023. Photograph by Maeva Pimo. © GloCo 428
13.3 Case patrimoniale Bapa, western Cameroon, 2018. Photograph by Honoré Tchatchouang. © GloCo 429
13.4 Front view of the entrance to the Grand Mosque in Porto-Novo, 2019. Photograph by Rachad Sanoussi. © Wikimedia 435
13.5 Rear view of Porto-Novo’s Grand Mosque, 2023. Photograph by Maeva Pimo. © GloCo 436
13.6 Electrical wire running from the outside to the inside of Porto-Novo’s Grand Mosque, 2023. Photograph by Maeva Pimo. © GloCo 437
13.7 Building inscription plaque, Porto-Novo, 2023. Photograph by Maeva Pimo. © GloCo 437
13.8 Afro-Brazilian house in Porto-Novo’s central market, 2023. Photograph by Crystallin Montcho. © GloCo 439
13.9 View of the Grand Mosque and the New Mosque, Porto-Novo, 2023. Photograph by Maeva Pimo. © GloCo 439
13.10 Ruined scaffolding consolidated by hand, Porto-Novo, 2023. Photograph by Crystallin Montcho. © GloCo 440
13.11 Modified roof of an Afro-Brazilian house, Porto-Novo, 2023. Photograph by Crystallin Montcho. © GloCo 441
13.12 Overview of some of the mud bricks used to build an Afro-Brazilian house, Porto-Novo, 2023, Photograph by Crystallin Montcho. © GloCo 441
13.13 Printed images to replace broken window panes, Porto-Novo, 2023. Photograph by Crystallin Montcho. © GloCo 442
13.14 Repaired calabash, Geneva, 2023. Private collection. Photograph by Noémie Etienne. © GloCo 445