![]() ![]() Guidelines towards the interpretation of complex MSI images and a discussion of the potential and limitations of relating multispectral data to chemical properties are presented. ![]() The physical properties observed from all of these images were then related to the more detailed information provided by complementary non-invasive techniques, such as fibre optic reflectance spectroscopy (FORS), and micro-invasive approaches, such as high-performance liquid chromatography mass spectrometry (HPLC-MS). Visible-induced visible luminescence (VIVL) and multiband-reflected (MBR) imaging were also explored for the first time with application to textiles, demonstrating their potential in mapping red and blue colourants respectively. This proved to be an important aid in planning more targeted and effective sampling strategies and facilitated comparisons between objects. Standardised acquisition and post-processing methods were applied to produce visible-reflected (VIS), ultraviolet-induced visible luminescence (UVL), infrared-reflected (IRR), infrared-reflected false colour (IRRFC), ultraviolet-reflected (UVR) and ultraviolet-reflected false colour (UVRFC) images that provided preliminary indications of the colourants used and their spatial distribution. The aim of this work is therefore to bridge this gap by showing how this non-invasive, relatively inexpensive and portable methodology can be used to map the photoluminescence and reflective characteristics of textiles under different wavelengths of light, and to provide qualitative and holistic insights into the chemical nature of the materials that compose them. Although the use of these techniques is well-established in the study of polychrome surfaces, they have only been sparingly and often unsystematically applied to the investigation of textiles. This work explores the use of multispectral imaging (MSI) techniques applied to the investigation of Late Antique (c. These results contribute important knowledge concerning how colours were depicted and the significance of whether pigments derived from the same source as dyes, and towards a deeper understanding of the craftsmen’s traditions. In some instances, the corresponding pigment was used for depicting garments, in this case madder lake for rendering madder-dyed textiles. The present examination has identified an overlap in the raw materials used for colouring textiles and for paint in antiquity. Therefore, in instances where there is no or only little evidence of Egyptian blue in the purple colour, indigo may have been used instead in the mixtures of textile dyes. Yet, other studies have confirmed that indigo, derived from the indigo plant (Indigofera tinctoria), was often employed in such portraits. However, in some cases it is unknown which blue pigment was used to create the purple colour. Madder lake is sometimes mixed with Egyptian blue in order to obtain the purple hue on the mummy portraits. In textile dying, madder red was tinted bluish using indigo or woad. The analysis demonstrates that shellfish purple was often imitated in textile dying as well as in painting by using madder and madder lake respectively. The mummy portraits were analysed with two non-invasive photographic methods: UV-induced fluorescence photography (UVF) and visible-induced luminescence (VIL). This study investigates the similarities between ancient polychrome painting and textile dyes with regard to the organic colourants used for the depiction of garments on Egyptian mummy portraits from the collections of the Ny Carlsberg Glyptotek, Copenhagen.
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