New Insights into the Cleaning of Paintings

More documents

Recommendations

Info

28 • smithsonian contributions to museum conservation APPLICATION EXAMPLE The picture depicting Saint Leonardus of Porto Maurizio was executed probably soon after Leonardus’s beatification in the year 1797. However, after he had been proclaimed a saint in 1867, the painting was altered in order to reflect Leonardus’s new status: the nimbus was added, as well as a secondary inscription, “St. Leonard.” At the same time the primary inscription was overpainted together with the whole background area. The exact location of both inscriptions within the painting’s structure was resolved by means of optical coherence tomography and is described elsewhere (Targowski et al., 2010). This study focuses on the application of optical coherence tomography to resolve the problems that emerged during the conservation of the painting. The overpaint was lying on three to four layers of varnish. It was decided that the overpaint would be removed while attempting to preserve the old varnishes underneath. Since, as the result of this treatment, the primary inscription was to be revealed, the aim of the research was to find the most safe and satisfactory treatment procedure. Cross- sectional views (OCT B- scans) were used both to assess noninvasively the integrity of the primary layers covered by the overpaint (Figure 1, left- hand side of the OCT images) and to examine the condition and thickness of these layers revealed as a result of the overpaint removal (Figure 1, right- hand side of the images). During the first stage of the experiment, small trials of overpaint removal were performed with different solvent compositions in the background area of the painting. The results were evaluated with OCT. The composition of isopropanol, water, and ammonium (9:1:1) applied with cotton swabs gave the most satisfactory and even results: the overpaint was removed completely, and the varnishes were preserved. However, further overpaint removal on the larger areas of the background proved less successful. OCT cross- sectional images revealed little holes in the varnish layer, which had started to occur before the overpainting was removed completely. Therefore, another set of OCT monitored trials was performed in order to evaluate the effect of using the same solvent composition, but with different removal procedures, such as rolling with a cotton swab, brushing, exposing to poultices, removing mechanically with a scalpel, and FIGURE 1. Trials of overpaint removal with different solvent compositions with the results evaluated by means of OCT. Consecutive layers are visible in the OCT tomograms: 1, original paint layer; 2, three to four layers of varnish; 3, overpaint layer. (top) Poor result obtained by removal with a mixture of ethanol and white spirit (1:1). (bottom) A satisfactory result obtained by removal with a mixture of isopropanol, water, and ammonia (9:1:1), where the overpaint was evenly removed and the varnish was preserved.
number 3 • 29 combinations thereof. In the trials carried out near the inscription, the best results were obtained by means of 3 minute poultice applications combined with a final solvent treatment with a cotton swab. However, in the area of the nimbus, which dates to the same alteration and has the same kind of binder, the best results were obtained using 15 minute poultice applications combined with a final mechanical cleaning with a scalpel. Finally, the established adequate overpaint removal procedures were employed for respective areas of the painting. CONCLUSIONS OCT imaging has proved useful in resolving certain problems during conservation of this eighteenth- century painting. It was possible to assess the integrity of the overpainted primary layers and to evaluate the results of overpaint removal in a fast and noninvasive way. This was a valuable aid, especially in the process of revealing the hidden inscription. acknowledges support from the Foundation for Polish Science within the Ventures Program, cofinanced by Operational Programme Innovative Economy within the European Regional Development Fund. REFERENCES Liang, H., B. Peric, M. Spring, D. Saunders, M. Hughes, and A. G. Podoleanu. 2008. “Non- Invasive Imaging of Subsurface Paint Layers with Optical Coherence Tomography.” In Conservation Science 2007, ed. J. H. Townsend, L. Toniolo, and F. Cappitelli, pp. 171–176. London: Archetype Publications. Szkulmowska, A., M. Góra, M. Targowska, B. Rouba, D. Stifter, E. Breuer, and P. Targowski. 2007. “The Applicability of Optical Coherence Tomography at 1.55 μm to the Examination of Oil Paintings.” In Lasers in the Conservation of Artworks, LACONA VI Proceedings, ed. J. Nimmrichter, W. Kautek, and M. Schreiner, pp. 487–492. Berlin: Springer. Targowski, P., M. Iwanicka, L. Tymińska- Widmer, M. Sylwestrzak, and E. A. Kwiatkowska. 2010. Structural Examination of Easel Paintings with Optical Coherence Tomography. Accounts of Chemical Research, 43(6):826–836. http:// dx.doi.org/10.1021/ar900195d. Acknowledgments This work was supported by Polish government research grants for the years 2008–2011. Magdalena Iwanicka additionally
Page 1 and 2: Smithsonian Institution Scholarly P
Page 3 and 4: smithsonian contributions to museum
Page 5 and 6: Contents PREFACE ACKNOWLEDGMENTS
Page 7: number 3 • v Extended Abstract—
Page 10 and 11: viii • smithsonian contributions
Page 13 and 14: The Removal of Patina Stephen Gritt
Page 15 and 16: number 3 • 3 and conceals its bea
Page 17: number 3 • 5 REFERENCES Algarotti
Page 20 and 21: 8 • smithsonian contributions to
Page 29 and 30: Surface Cleaning of Paintings and P
Page 31 and 32: number 3 • 19 methods for cleanin
Page 33 and 34: number 3 • 21 not the varnish its
Page 35 and 36: Extended Abstract—A Preliminary I
Page 37: number 3 • 25 FIGURE 3. Detail of
Page 43 and 44: Extended Abstract—A New Documenta
Page 45: number 3 • 33 FIGURE 2. Recording
Page 63 and 64: Oil Paints: The Chemistry of Drying
Page 65 and 66: number 3 • 53 FIGURE 3. Weight ch
Page 67 and 68: number 3 • 55 FIGURE 7. Formation
Page 69 and 70: number 3 • 57 FIGURE 11. Differen
Page 71 and 72: The Influence of Pigments and Ion M
Page 73 and 74: number 3 • 61 FIGURE 3. Mechanica
Page 75 and 76: number 3 • 63 FIGURE 7. Mechanica
Page 77 and 78: number 3 • 65 observation that co
Page 79: number 3 • 67 • Not all pigment
Page 90 and 91:
78 • smithsonian contributions to
Page 92 and 93:
Page 94 and 95:
Page 96 and 97:
Page 98 and 99:
Page 101 and 102:
Characterization and Stability Issu
Page 103 and 104:
number 3 • 91 FIGURE 2. Film form
Page 105 and 106:
number 3 • 93 (Saunders, 1973). T
Page 107:
number 3 • 95 allows identificati
Page 110 and 111:
Page 112 and 113:
100 • smithsonian contributions t
Page 114 and 115:
Page 116 and 117:
Page 119 and 120:
Sensitivity of Oil Paint Surfaces t
Page 121 and 122:
number 3 • 109 Analytical Methods
Page 123 and 124:
number 3 • 111 The method for ass
Page 125 and 126:
number 3 • 113 FIGURE 6. Secondar
Page 127 and 128:
Extended Abstract—The Effect of C
Page 129:
number 3 • 117 Table 1. Surface m
Page 132 and 133:
Page 134 and 135:
Page 137 and 138:
Multitechnique Approach to Evaluate
Page 139 and 140:
number 3 • 127 RESULTS AND DISCUS
Page 141 and 142:
number 3 • 129 FIGURE 4. The SEM
Page 143 and 144:
number 3 • 131 FIGURE 7. (top) St
Page 145 and 146:
number 3 • 133 FIGURE 10. Stress-
Page 147 and 148:
Extended Abstract—A Preliminary S
Page 149:
number 3 • 137 Acknowledgments An
Page 152 and 153:
Page 154 and 155:
Page 156 and 157:
Page 159 and 160:
Cleaning of Acrylic Emulsion Paints
Page 161 and 162:
number 3 • 149 advocates of publi
Page 163 and 164:
number 3 • 151 2.5, 3.5, 4.5, 5.5
Page 165 and 166:
number 3 • 153 ethoxylate units i
Page 167 and 168:
number 3 • 155 FIGURE 5. Golden A
Page 169:
number 3 • 157 alien und Methoden
Page 172 and 173:
Page 174 and 175:
Page 176 and 177:
Page 178 and 179:
Page 181 and 182:
Extended Abstract—The Removal of
Page 183 and 184:
number 3 • 171 RESULTS AND DISCUS
Page 185 and 186:
number 3 • 173 FIGURE 3. The SEM
Page 187 and 188:
Extended Abstract—Cleaning Issues
Page 189:
number 3 • 177 Acknowledgments Th
Page 192 and 193:
Page 194 and 195:
Page 197 and 198:
Effects of Commercial Soaps on Unva
Page 199 and 200:
number 3 • 187 The aqueous and or
Page 201 and 202:
number 3 • 189 all tests. The res
Page 203 and 204:
number 3 • 191 palmitic and stear
Page 205 and 206:
FIGURE 5. Scanning electron microsc
Page 207 and 208:
number 3 • 195 FIGURE 6. Confocal
Page 209 and 210:
Extended Abstract—Tissue Gel Comp
Page 211:
number 3 • 199 • The capillary
Page 214 and 215:
Page 217 and 218:
Extended Abstract—Use of Agar Cyc
Page 219:
number 3 • 207 FIGURE 4. The FTIR
Page 222 and 223:
Page 224 and 225:
Page 226 and 227:
Page 228 and 229:
Page 230 and 231:
Page 233 and 234:
Extended Abstract—The Schlürfer:
Page 235 and 236:
number 3 • 223 FIGURE 3. Removal
Page 237 and 238:
Extended Abstract—Surface Cleanin
Page 239:
number 3 • 227 Table 3. Cleaning
Page 242 and 243:
Page 244 and 245:
Page 246 and 247:
Page 249 and 250:
Extended Abstract—Laser Cleaning
Page 251 and 252:
Ending Note: Summary of Panel Discu
Page 253 and 254:
Index TABLES in BOLD; Figures in It
Page 255 and 256:
number 3 • 243 polyvinyl acetate
show all

New Insights into the Cleaning of Paintings

Create successful ePaper yourself

Delete template?

Save as template?