Multispectral imaging (MSI) techniques are a system of broadband images captured using selected ranges of wavelengths of light extended beyond the capabilities of the human eye to record reflectance and luminescence properties of the organic and inorganic materials, including dyes. This allows the identification of the spatial distribution, and, in some cases, the chemical nature of colorants present on the mummy wrappings and facilitates comparisons between objects.
The detection of dyed yarns is challenging since they are mostly degraded due to bleaching agents and the combination of different materials used in mordanting. The usual fading of textiles, the prolonged exposure to light, and the huge layer of soiling often present further affect the recognition of coloring matters. Fortunately, in some cases the intricate overlapping of the bandages hid a section of textiles, thus securing their original color.
The MSI techniques are performed using a full-spectrum modified camera, different radiation sources and a set of filters.
The produced reflectance and luminescence images (Visible-reflected (VIS), Infrared-reflected (IRR), Ultraviolet-reflected (UVR), False-colour reflected (IRRFC, UVRFC), Ultraviolet-induced luminescence (UVL)) reveal emitting materials and their reflectance and absorbance properties, which often help in identify dyes as well as to assess their condition.