What about discoloration in plastic artifacts? The use of Fiber Optic Reflectance Spectroscopy in the scope of conservation


  • Eva Mariasole Angelin Department of Conservation and Restoration and LAQV-REQUIMTE, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal https://orcid.org/0000-0002-9259-674X
  • Costanza Cucci ‘‘Nello Carrara’’ Institute of Applied Physics of the Italian National Research Council (IFAC-CNR), Sesto Fiorentino, Italy https://orcid.org/0000-0001-8534-7465
  • Marcello Picollo ‘‘Nello Carrara’’ Institute of Applied Physics of the Italian National Research Council (IFAC-CNR), Sesto Fiorentino, Italy




historical plastic objects, discoloration, FORS, in situ analysis, colorimetry


Fiber Optic Reflectance Spectroscopy (FORS) is a well-established technique for the study of traditional artworks. Nevertheless, its application for the analysis of modern and contemporary materials such as plastics is still a pioneering line of research. In this work, the application of FORS for the discoloration assessment of cultural heritage plastics is presented. The spectroscopic method successfully characterized in situ the discoloration of a selection of naturally aged historical plastic objects, and results of yellowing and fading measurements are discussed. Even though further research studies are required to elucidate the potentialities and limitations of FORS in the investigation of cultural heritage plastics, this study paves the way for its application as a preliminary tool for the detection of incipient and severe discoloration in the plastic heritage caused by polymer and colorant degradation (e.g. yellowing, darkening and fading). The results suggested that FORS may be considered a reliable method for in-situ rapid characterization and monitoring of cultural heritage plastics degradation phenomena in museums in the scope of collection care.


Allen, N. S. and McKellar, J. F. (1980) Photochemistry of Dyed and Pigmented Polymers. Essex: Applied Science Pub.
Allen, N.S. and Edge, M. (1992) Fundamentals of polymer degradation and stabilization. London, UK: Elsevier Applied Science Ltd.
Angelin, E. M., França de Sá, S., Picollo, M., Nevin, A., Callapez, M. E. and Melo, M. J. (2021) ‘Theidentification of synthetic organic red pigments in historical plastics: developing an in situ analytical protocol based on Raman microscopy’, Journal of Raman Spectroscopy, 52, pp. 145-158. doi: 10.1002/jrs.5985.
Boldizar, A. and Möller, K. (2003) ‘Degradation of ABS during repeated processing and accelerated ageing’, Polymer Degradation and Stability, 81, pp. 359-366. doi:10.1016/S0141-3910(03)00107-1.
Callapez, M. E. (2017) ‘An Interdisciplinary Project on the History of Plastics in Portugal’, eplastory-Journal of Historic Polymeric Materials, Plastics Heritage and History, 1, pp. 1-8.
Charvat, R. A. (2004) Coloring of Plastics. 2nd eds., New Jersey, US: Wiley.
Cucci, C., Bigazzi, L. and Picollo, M. (2013) ‘Fibre Optic Reflectance Spectroscopy As A Non-Invasive Tool For Investigating Plastics Degradation In Contemporary Art Collections: A Methodological Study On An Expanded Polystyrene Artwork’, Journal of Cultural Heritage, 14, pp. 290–296. doi: 10.1016/j.culher.2012.08.003.
Feller, R. J. (2001) Color Science in the Examination of Museum Objects. USA: J. Paul Getty Trust.
França de Sá, S., da Cruz, S. M., Callapez, M. E. and Carvalho, V. (2020) ‘Plastics that made history - the contribution of conservation science for the history of the Portuguese Plastics Industry’, Conservar Património, pp 1-29. doi: 10.14568/cp2019017.
Hawkins, W.L. (1984) Polymer Degradation and Stabilization. Berlin, Germany: Springer-Verlag.
Hunger, K. and Schmidt, M. U. (2018) Industrial Organic Pigments: Production, Crystal Structure, Properties, Applications. 4th eds., Weinheim, Germany: Wiley.
Izzo, F. C., Carrier, A., Bartolozzi, G, van Keulen, H., Lorenzon, I., Balliana, E., Cucci, C., Grazzi, F. and Picollo M. (2019) ‘Elucidating the composition and the state of conservation of nitrocellulose-based animation cells by means of non-invasive and micro-destructive techniques’, Journal of Cultural Heritage, 35, pp. 254-262. doi: 10.1016/j.culher.2018.09.010.
Lavédrine, B., Fournier, A., and Martin, G. (2012) Preservation of Plastic Artefacts in Museum Collections. Paris, France: Comité Des Travaux Historiques et Scientifiques (CTHS).
Lewis, P. A. (1988) Pigment Handbook: Properties and Economics. Vol I, 2nd eds., Canada: Wiley.
Müller A. (2003) Coloring of Plastics. Munich, Germany: Verlag.
Oleari, C. (2016) Standard Colourimetry: Definitions, Algorithms and Software. UK: Wiley.
Pintus, V., Piccolo, A., Vetter, W., Moretto L. G., Sterflinger, K. and Schreiner M. (2021) ‘What about Phenol Formaldehyde (PF) Foam in Modern-Contemporary Art? Insights into the Unaged and Naturally Aged Material by a Multi-Analytical Approach’, Polymers, 13, pp. 1964. doi: 10.3390/polym13121964.
Quye, A. and Williamson, C. (1999) Plastics Collecting and Conserving. Edinburg, Scotland: NMS Pub.
Rabek, J.F. (1995) Polymer Photodegradation: Mechanisms and experimental methods. Dordrecht, Germany: Springer Science+Business Media.
Salman, S. and Al-Shama'a, N. (1991) ‘Effect of Thermal Aging on the Optical Properties of ABS Plastics’, Polymer-Plastics Technology and Engineering, 30, pp.343-349. doi: 10.1080/03602559108021000.
Saviello, D., Pouyet, E., Toniolo, L., Cotte, M. and Nevin, A. (2014) ‘Synchrotron-based FTIR microspectroscopy for the mapping of photo-oxidation and additives in acrylonitrile–butadiene–styrene model samples and historical objects’, Analytica Chimica Acta, 843, pp.59-72. doi: 10.1016/j.aca.2014.07.021.
Shashoua, Y. (2008) Conservation of Plastics. Oxford, UK: Butterworth-Heinemann.
Webber, T. G. (1979) Coloring of Plastics. Canada: Wiley.




How to Cite

Angelin, E. M., Cucci, C. and Picollo, M. (2022) “What about discoloration in plastic artifacts? The use of Fiber Optic Reflectance Spectroscopy in the scope of conservation”, Cultura e Scienza del Colore - Color Culture and Science, 14(01), pp. 87–93. doi: 10.23738/CCSJ.140111.