Application of a hyperspectral camera for colorimetric and spectroscopic measurements under natural light on outdoors artistic polychrome surfaces




Hyperspectral imaging, polychromatic surfaces, natural light, Specim IQ, colorimetric analysis


The aim of this study is to define the parameters of accuracy of data acquired with the Specim IQ hyperspectral camera for CIE colorimetric measurements of polychrome surfaces in outdoor architectural settings with natural light. Furthermore, the study aims to compare the data obtained by the Specim IQ camera with those acquired by a contact colorimeter (Konica-Minolta CM-700d). CIE colorimetric measurements are generally acquired with dedicated instruments, such as tristimulus method colorimeters and spectrophotometric method, which require contact with the surface and coverage areas on the order of tens of mm2. The characteristics of requiring contact and analyzing very small areas can severely limit the study of artistic polychrome surfaces. This is because it may not always be possible to touch the analyzed surface and the measured areas may not necessarily be representative of a wider area of the same color. To overcome these limitations, one possible alternative is to use imaging techniques to acquire measurements from a distance while covering larger areas of the analyzed artifact. To calculate the colorimetric values as defined by the CIE and to also have the possibility to acquire spectroscopic data it was used the Specim IQ compact hyperspectral camera. This camera acquires 204 bands with a spectral resolution of 7 nm and an acquisition step of 3.5 nm in the 400-1000 nm operating range.

Colorimetric data were initially acquired on eight different color targets and two color palettes using a spectrocolorimeter. Subsequently, outdoor tests were conducted on the same samples under natural light using the Specim IQ hyperspectral camera. As a result, the operating characteristics of the hyperspectral camera for outdoor measurements aimed at studying the color of polychrome surfaces were defined.


Amigo, J. M. (2019) Hyperspectral Imaging, Volume 32 - 1st Edition. Elsevier.

Bai, D., Messinger, D. W. and Howell, D. (2019) ‘A hyperspectral imaging spectral unmixing and classification approach to pigment mapping in the Gough & Selden Maps’, Journal of the American Institute for Conservation, 58(1–2), pp. 69–89. doi: 10.1080/01971360.2019.1574436.

Behmann, J. et al. (2018) ‘Specim IQ: Evaluation of a New, Miniaturized Handheld Hyperspectral Camera and Its Application for Plant Phenotyping and Disease Detection’, Sensors, 18(2). doi: 10.3390/s18020441.

CIE Publication No 15.2, 1986. Colorimetry (2nd edition); Commission International de I’Eclairage (CIE), Central Bureau of the CIE: Vienna, Austria.

CIE 15:2004, 2004. Technical Report. Colorimetry, 3rd ed.; Commission International de I’Eclairage (CIE), Central Bureau of the CIE: Vienna, Austria.

Cucci, C. et al. (2017) ‘Bridging research with innovative products: a compact hyperspectral camera for investigating artworks: a feasibility study’, in Optics for Arts, Architecture, and Archaeology VI. Optics for Arts, Architecture, and Archaeology VI, SPIE, pp. 17–29. doi: 10.1117/12.2270015.

Cucci, C. et al. (2018) ‘The illuminated manuscript Corale 43 and its attribution to Beato Angelico: Non-invasive analysis by FORS, XRF and hyperspectral imaging techniques’, Microchemical Journal, 138, pp. 45–57. doi: 10.1016/j.microc.2017.12.021.

Cucci, C. et al. (2018) ‘Potentialities of reflectance hyperspectral imaging technique in the field of architecture’, in Colour and Colorimetry Multidisciplinary Contributions. 14th Color Conference, Firenze: Veronica Marchiafava, Lia Luzzato, pp. 155–166.

Cucci, C. et al. (2021) ‘Reflectance hyperspectral data processing on a set of Picasso paintings: which algorithm provides what? A comparative analysis of multivariate, statistical and artificial intelligence methods’, in Groves, R. and Liang, H. (eds) Optics for Arts, Architecture, and Archaeology VIII. Optics for Arts, Architecture, and Archaeology (O3A) VIII, Online Only, Germany: SPIE, p. 1. doi: 10.1117/12.2593838.

Cherubini, F. et al. (2019) ‘The survey of color in architecture: comparison between new and old methodologies’, in Color and Colorimetry Multidisciplinary Contributions. 15th Color Conference, Macerata: Aldo Bottoli, Veronica Marchiafava, pp. 23–27.

Cherubini, F. et al. (no date) ‘Application of hyperspectral camera and spectrocolorimeter for spectroscopic and colorimetric measurements on polychrome surfaces in a controlled environment: pros and cons of the presented technologies’, in International Colour Association (AIC) Conference 2021 Milano: AIC, pp. 745–749.

Cherubini, F. et al. (2023) ‘Application of a hyperspectral camera for colorimetric measurements on polychrome surfaces in a controlled environment and evaluation of three image processing software for displaying colorimetric data: Pros and cons of the methodology presented’, Color Research & Application, 48(2), pp. 210–221. doi: 10.1002/col.22835.

Deborah, H., George, S. and Hardeberg, J. Y. (2019) ‘Spectral-divergence based pigment discrimination and mapping: A case study on The Scream (1893) by Edvard Munch’, Journal of the American Institute for Conservation, 58(1–2), pp. 90–107. doi: 10.1080/01971360.2018.1560756.

Delaney, J. K. et al. (2010) ‘Visible and infrared imaging spectroscopy of Picasso’s Harlequin musician: mapping and identification of artist materials in situ’, Applied Spectroscopy, 64(6), pp. 584–594. doi: 10.1366/000370210791414443.

ISO/CIE 10526, 1991. CIE standard colorimetric illuminants, International Organization for Standardization, Geneva (CH).

ISO/CIE 10527, 1991. CIE standard colorimetric observers, International Organization for Standardization, Geneva (CH).

Kleynhans, T. et al. (2020) ‘An alternative approach to mapping pigments in paintings with hyperspectral reflectance image cubes using artificial intelligence’, Heritage Science, 8(1), p. 84. doi: 10.1186/s40494-020-00427-7.

Kubik, M. (2007) ‘Chapter 5 Hyperspectral Imaging: A New Technique for the Non-Invasive Study of Artworks’, in Creagh, D. and Bradley, D. (eds) Physical Techniques in the Study of Art, Archaeology and Cultural Heritage. Elsevier (Physical Techniques in the study of Art, Archaeology and Cultural Heritage), pp. 199–259. doi: 10.1016/S1871-1731(07)80007-8.

Luo, G. et al. (2016) ‘Minimum Noise Fraction versus Principal Component Analysis as a Preprocessing Step for Hyperspectral Imagery Denoising’, Canadian Journal of Remote Sensing, 42(2), pp. 106–116. doi: 10.1080/07038992.2016.1160772.

Mounier, A. and Daniel, F. (2015) ‘Hyperspectral imaging for the study of two thirteenth-century Italian miniatures from the Marcadé collection, Treasury of the Saint-Andre Cathedral in Bordeaux, France’, Studies in Conservation, 60(sup1), pp. S200–S209. doi: 10.1179/0039363015Z.000000000225.

Oleari, C. (2016) Standard colorimetry: definitions, algorithms, and software. Chichester, West Sussex, UK: John Wiley & Sons, Inc.

Picollo, M. et al. (2020) ‘Hyper-Spectral Imaging Technique in the Cultural Heritage Field: New Possible Scenarios’, Sensors, 20(10), p. 2843. doi: 10.3390/s20102843.

Ricciardi, P. et al. (2012) ‘Near Infrared Reflectance Imaging Spectroscopy to Map Paint Binders In Situ on Illuminated Manuscripts’, Angewandte Chemie International Edition, 51(23), pp. 5607–5610. doi: 10.1002/anie.201200840.

Sciuto, C. et al. (2022) ‘What Lies Beyond Sight? Applications of Ultraportable Hyperspectral Imaging (VIS-NIR) for Archaeological Fieldwork’, Journal of Field Archaeology, 47(8), pp. 522–535. doi: 10.1080/00934690.2022.2135066.

Sharma, G., Wu, W. and Dalal, E. N. (2005) ‘The CIEDE2000 color-difference formula: Implementation notes, supplementary test data, and mathematical observations’, Color Research & Application, 30(1), pp. 21–30. doi: 10.1002/col.20070.

Signoroni, A. et al. (2020) ‘Spatial–Spectral Evidence of Glare Influence on Hyperspectral Acquisitions’, Sensors, 20(16), p. 4374. doi: 10.3390/s20164374.

Striova, J., Dal Fovo, A. and Fontana, R. (2020) ‘Reflectance imaging spectroscopy in heritagescience’, La Rivista del Nuovo Cimento, 43(10), pp. 515–566. doi: 10.1007/s40766-020-00011-6.







How to Cite

“Application of a hyperspectral camera for colorimetric and spectroscopic measurements under natural light on outdoors artistic polychrome surfaces” (2023) Cultura e Scienza del Colore - Color Culture and Science, 15(02), pp. 57–65. doi:10.23738/CCSJ.150207.