Jan Dariusz Cutajar

• Cutajar, Jan Dariusz; Steindal, Calin Constantin; Caruso, Francesco; Joseph, Edith & Frøysaker, Tine (2024). Spectral- and image-based metrics for evaluating cleaning tests on unvarnished painted surfaces. Preprints. ISSN 2310-287X. doi: 10.20944/preprints202407.0896.v2. Full text in Research Archive
• Cutajar, Jan Dariusz; Steindal, Calin Constantin; Caruso, Francesco; Joseph, Edith & Frøysaker, Tine (2024). Spectral- and Image-Based Metrics for Evaluating Cleaning Tests on Unvarnished Painted Surfaces. Coatings. 14(8). doi: 10.3390/coatings14081040. Full text in Research Archive Show summary

  Despite advances in conservation–restoration treatments, most surface cleaning tests are subjectively evaluated. Scores according to qualitative criteria are employed to assess results, but these can vary by user and context. This paper presents a range of cleaning efficacy and homogeneity evaluation metrics for appraising cleaning trials, which minimise user bias by measuring quantifiable changes in the appearance and characteristic spectral properties of surfaces. The metrics are based on various imaging techniques (optical imaging by photography using visible light (VIS); spectral imaging in the visible-to-near-infrared (VNIR) and shortwave infrared (SWIR) ranges; chemical imaging by Fourier transform infrared (FTIR) spectral mapping in the mid-infrared (MIR) range; and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX) element mapping). They are complemented by appearance measurements (glossimetry and colourimetry). As a case study showcasing the low-cost to high-end metrics, agar gel spray cleaning tests on exposed ground and unvarnished oil paint mock-ups are reported. The evaluation metrics indicated that spraying agar (prepared with citric acid in ammonium hydroxide) at a surface-tailored pH was as a safe candidate for efficacious and homogenous soiling removal on water-sensitive oil paint and protein-bound ground. Further research is required to identify a gel-based cleaning system for oil-bound grounds.

• Grøntoft, Terje & Cutajar, Jan Dariusz (2023). The role of SVOCs in the initial film formation and soiling of unvarnished paintings. Heritage Science. 11(1). doi: 10.1186/s40494-023-01115-y. Full text in Research Archive Show summary

  In recent years increased research efforts and environmental improvements have been directed towards the preventive conservation of the monumental, unvarnished oil paintings on canvas (1909–1916) by Edvard Munch (1863–1944) housed in the University of Oslo Aula. Surface soiling of the paintings has been a documented issue since their display, and the modern-day effect of air-borne particulates and gases on the painting surfaces remains hitherto undocumented. For the first time in the Aula, this study has measured the in-situ time-dependent mass deposit of air pollution onto vertical surfaces over the period of one year (2021–2022). Concomitant measurements of the concentrations of ozone (O3) and nitrogen dioxide (NO2) were also taken, to complement periodic data from 2020. The mass deposit was measured through incremental weight changes of Teflon membrane filters, and quartz filters for analysis of elemental/organic carbon (EC/OC), whilst the gaseous pollutants were measured using passive gas samplers. Indoor-to-outdoor ratios (I/O) for O3 were noted to be higher than those suggested by earlier data, whereas NO2 I/O ratios were found to be lower, indicating a stronger oxidising atmosphere in the Aula. Just over half of the deposited mass on the quartz filters was found to be OC, with no EC detected. Surprisingly, an overall decrease in the mass deposit from three to twelve months was measured on the Teflon membrane filters. It was hypothesised, based on models reported in the literature, that the source of the OC on the filters was mainly gaseous, semi-volatile organic compounds (SVOCs), which were present in an adsorption/desorption equilibrium that was dependent on possible SVOC emission episodes, relative humidity levels, gaseous oxidative reactions and the particulate matter deposit. A simple mathematical model is proposed to rationalise the observed mass deposits on the filters, together with a discussion of uncertainties affecting the measurements. The hypothesis preliminarily indicates the possible and previously unconsidered role of SVOCs on the initial film formation of soiling layers on the Aula paintings, and could bear implications for their monitoring in the preventive care of unvarnished oil paintings on canvas.

• Grøntoft, Terje & Cutajar, Jan Dariusz (2023). A hypothesis on the initial film formation by deposition from the indoor air on clean filter samples and its relevance for unvarnished oil paintings on canvas. Research Square. ISSN 2693-5015. doi: 10.21203/rs.3.rs-3316667/v1. Full text in Research Archive
• Cutajar, Jan Dariusz; Babini, Agnese; Deborah, Hilda; Hardeberg, Jon Yngve; Joseph, Edith & Frøysaker, Tine (2022). Hyperspectral Imaging Analyses of Cleaning Tests on Edvard Munch's Monumental Aula Paintings. Studies in Conservation. ISSN 0039-3630. 67(1), p. 59–68. doi: 10.1080/00393630.2022.2054617. Full text in Research Archive Show summary

  The development of innovative applications of imaging technologies for monitoring change in cultural heritage objects is central to the CHANGE-ITN project. Within this framework, the authors’ ongoing work targets the harnessing of hyperspectral imaging (HSI) for the documentation of cleaning treatments on the monumental University of Oslo Aula unvarnished oil paintings on canvas (1909–1916) by Edvard Munch (1863–1944). This is applicable to unvarnished paint surfaces in general. Particularly, this paper evaluates HSI techniques for the investigation of cleaning tests carried out in 2008, which targeted the removal of visible, ingrained particulate matter from Munch's unvarnished oil paints and exposed grounds on Kjemi (1914–1916). An exploratory in situ HSI campaign using visible to near-infrared (VNIR) and short-wave infrared (SWIR) cameras was undertaken to capture the soiled or previously cleaned areas on the painting's surface, with comparisons to analogous mock-ups. Principal component analysis (PCA) was used to extract information about possible trends with respect to the soiling. Results indicate that in both VNIR and SWIR ranges, the intensity of reflectance can be used to discriminate statistically between soiled and unsoiled/cleaned areas, whereas in SWIR, combination and first overtone bands of oil peaks can also serve as markers.

• Cutajar, Jan Dariusz; Hatchfield, Pamela; Batkin-Hall, Janelle; Bourse, Camille & Mayberger, Evelyn (2021). Conservation and preservation strategies for royal painted tombs in Kurru, Sudan: Acknowledging the past while planning for the future. In Bridgland, Janet (Eds.), Transcending boundaries : Integrated approaches to conservation : ICOM-CC 19th Triennial Conference Preprints, Beijing 17-21 May 2021. International Council of Museums Committee for Conservation (ICOM-CC). ISSN 9782491997144. p. 1–9. Full text in Research Archive
• Hatchfield, Pamela; Batkin-Hall, Janelle; Bourse, Camille; Cutajar, Jan Dariusz & Mayberger, Evelyn (2020). Working together: community, conservation, and preservation strategies for royal painted tombs at El-Kurru, Sudan. Studies in Conservation. ISSN 0039-3630. p. 132–138. doi: 10.1080/00393630.2020.1783165. Full text in Research Archive
• Cutajar, Jan Dariusz (2019). Kussenkasten in the Dutch golden age: technical insights into Knole’s ebony kussenkast from a conservation perspective. Furniture History. ISSN 0016-3058. p. 51–70. Full text in Research Archive
• Bristow, Hana & Cutajar, Jan Dariusz (2017). Archaeological Glass Conservation: Comparative Approaches and Practicalities of Using Acrylic Resin Films as Gap Fills. AIC Objects Specialty Group Postprints. ISSN 2169-1290. 24, p. 188–206. Full text in Research Archive
• Cutajar, Jan Dariusz; Duckor, Abigail; Sully, Dean & Fredheim, L. Harald (2016). A significant statement: new outlooks on treatment documentation. Journal of the Institute of Conservation. ISSN 1945-5224. 39(2), p. 81–97. doi: 10.1080/19455224.2016.1212717. Full text in Research Archive

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• Romani, Martina; Ortega, Mercedes; Caruso, Francesco; Laserna, Olivia Gómez; Zarandona, Iratxe & Cutajar, Jan Dariusz [Show all 9 contributors for this article] (2024). Developing environmentally sustainable solutions for cleaning Edvard Munch’s monumental Aula paintings: a materials science-driven multi-analytical methodology. Full text in Research Archive
• Laserna, Olivia Gómez; Zarandona, Iratxe; Romani, Martina; Caruso, Francesco; Nualart-Torroja, Anna & Martí, Africa Pitarch [Show all 10 contributors for this article] (2024). Nanocellulose aerogels and hydrogels as new generation materials for the green transition in painting conservation. Full text in Research Archive
• Zarandona, Iratxe; Laserna, Olivia Gómez; Romani, Martina; Cutajar, Jan Dariusz; Frøysaker, Tine & Lizundia, Erlantz [Show all 7 contributors for this article] (2024). Cellulose nanofiber-based hydrogels as a sustainable alternative for soiling removal on canvas paintings. Full text in Research Archive
• Cutajar, Jan Dariusz; Steindal, Calin Constantin; Joseph, Edith; Caruso, Francesco; Hardeberg, Jon Yngve & Frøysaker, Tine (2023). Spectral- and image-based documentation metrics for the evaluation of conservation cleaning treatments. Archiving Conference. ISSN 2161-8798. Full text in Research Archive
• Cutajar, Jan Dariusz; Babini, Agnese; Deborah, Hilda; Hardeberg, Jon Yngve; Joseph, Edith & Frøysaker, Tine (2022). Hyperspectral imaging analyses of cleaning tests on Edvard Munch’s monumental Aula paintings. Full text in Research Archive
• Cutajar, Jan Dariusz; Hardeberg, Jon Yngve; Joseph, Edith & Frøysaker, Tine (2022). Hyperspectral-based documentation of cleaning tests on Munch’s monumental Aula paintings: PCA, NDI and NMF maps. Full text in Research Archive
• Cutajar, Jan Dariusz; Grillini, Federico; Babini, Agnese; Hardeberg, Jon Yngve & Frøysaker, Tine (2022). n situ hyperspectral imaging of monumental oil paintings: a practical approach for acquisitions on scaffolding and post-processing guidelines for conservators. Full text in Research Archive
• Cutajar, Jan Dariusz; joseph, edith; Hardeberg, Jon Yngve; Steindal, Calin Constantin & Frøysaker, Tine (2022). Cleaning unvarnished oil paint mock-ups. Spectral imaging maps for assessing soiling removal. Full text in Research Archive
• Cutajar, Jan Dariusz; Joseph, Edith; Hardeberg, Jon Yngve; Steindal, Calin Constantin & Frøysaker, Tine (2022). Spectral imaging for cleaning paintings. Mapping soiling removal by rigid agar gel spray from unvarnished oil paint mock-ups of Munch's monumental Aula paintings. Full text in Research Archive
• Cutajar, Jan Dariusz; Hardeberg, Jon Yngve; Joseph, Edith & Frøysaker, Tine (2020). MUNCH: Monitoring Munch’s monumental unvarnished oil paintings – exploring novel change documentation methods and cleaning techniques using hyperspectral imaging. Full text in Research Archive
• Cutajar, Jan Dariusz (2018). Breathing new life into Knole's kussenkast. Full text in Research Archive
• Cutajar, Jan Dariusz (2025). Surface cleaning & spectral imaging: An interdisciplinary study applied to Munch's monumental unvarnished Aula paintings. Universitetet i Oslo. Full text in Research Archive Show summary

  The removal of soiling from the coloured surfaces of the unvarnished Aula paintings on canvas (1909–1916) by Edvard Munch (1863–1944) has been the focus of conservation research due to the inherent fragility and monumental scale of the paintings, which present specific challenges for surface cleaning, particularly their water- and friction-sensitive nature. To better understand the soiling, research into environmental pollutants in the Aula revealed that soiling layer formation is a dynamic process involving complex interactions between semi-volatile organic compounds (emitted via housekeeping practices), relative humidity, and oxidative reactions. The Aula's unexpectedly oxidising atmosphere, characterised by modified ozone and nitrogen dioxide ratios, suggests increased potential for surface interactions and soiling processes through enhanced oxidative reactions with painting materials. Within the Aula context, spectral imaging techniques offered a novel, non-contact methodology for documenting surface cleaning on large-scale surfaces. A comprehensive surface cleaning study was developed to trial a new agar spray cleaning technique and assess soiling mapping via spectral methods. Artificially aged mock-ups, based on the painting Kjemi (1914–1916), were created and cleaned using this technique. A new suite of image-based and spectral-based metrics was developed to evaluate cleaning efficacy and homogeneity, providing low-cost to high-precision evaluation tools. Based on its soiling removal efficacy, highly controlled cleaning solution release, and specifics of application, the evaluations highlighted agar spray as a potential candidate for the cleaning of water-sensitive unvarnished surfaces, with further testing recommended. In situ spectral acquisitions of previous cleaning tests on Kjemi served to investigate soiling removal on complex, degraded surfaces. Integrating multiple analytical techniques (hyperspectral imaging, point-based X-ray fluorescence, and diffuse reflectance spectroscopy), pigment distributions were mapped, and material compositions studied. Results revealed that soiling removal could be documented in the visible near-infrared range using spectral unmixing algorithms. Multivariate statistical analysis showed that exploiting spectral variations between soiled and cleaned regions could allow for mapping soiling in the shortwave infrared range, using principal component analysis in combination with normalised difference imaging. This is the first study to have examined Munch’s Aula paintings and related analogous mock-ups through spectral imaging. As such, the thesis explores avenues on the potential use of spectral imaging for the documentation of surface cleaning on similar unvarnished surfaces. Moreover, it contributes to broadening the possibilities for the future care and preservation of Munch’s monumental artworks. It is recommended to view the PDF files in two-page format

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