Identification of colourants in icons of the Cretan School of iconography using Raman spectroscopy and liquid chromatography

The stratigraphies of twenty five (25) samples removed from twenty (20) icons of the Cretan School of iconography are studied using Optical Microscopy and micro-Raman spectroscopy. The objects are dated in 15th–17th c. and belong to the collection of the Benaki Museum, Athens, Greece. Cinnabar, red ochre, minium, yellow ochre, azurite, malachite, lapis lazuli, lead white, carbon black, and indigo are identified in the cross-sections of the icon samples using Raman spectroscopy.For four (4) icons no data were available from previous investigations regarding the identity of the red organic colourants. Microsamples were extracted from these icons and analysed using High Performance Liquid Chromatography coupled to a Diode Array Detector (HPLC–DAD). The HPLC–DAD results provide support to recently published reports which showed that kermes used in Cretan icons of the early period was replaced by cochineal after the discovery of the New World. The study of the cross-sections of the icon samples with Optical Microscopy revealed the combinations of the various inorganic and organic colourants.

► We study 25 samples removed from icons of the Cretan School (15th–17th c.).
► Inorganic pigments are identified using micro-Raman spectroscopy.
► Organic colourants are identified using HPLC–DAD.
► The stratigraphies of the samples are revealed using optical microscopy.