Pigment study of the 21st Egyptian Dynasty Yellow Coffins from the Louvre collection : analytical methodology and first results

International audienceThis physicochemical study aims to identify materials from the polychromy of 10 coffins from the collection of the Egyptian Antiquity Department of the Louvre Museum.The protocol put in place could be divided in two steps: first in-situ non-invasive analysis and then ones done on micro-samples. A scientific review with imaging file (multiscale and multispectral, and X-Ray radiography) is done to complete information about manufacturing and objects life. We here just evoke pigment identification, varnish, binder or wood one depends to another protocol.The first phase consists on reviews and analyses of the object surface (XRF, FORS, IR) which only give preliminary results about the chemical nature of materials responsible of the color. To get a better appreciation of the stratigraphy, micro-sampling is inevitable and can be used for various techniques (SEM-EDS, Raman, IRTF, XRD, GCMS). With microscopic observations, we have highlighted a complex painting manufacturing. Indeed, the stratigraphy differs according to the area studied (internal or external wall etc.). Presence of mixing, variation of layers thickness or particle sizes were also noted. SEM imaging permit to identify clearly by grain morphology two types of calcium and magnesium carbonates, information that elementary composition alone doesn’t give. Coupled with EDS it showed that green are made of synthetic copper compounds, organometallic or amorphous silicate.This work is a part of the Vatican Coffin Project, collaboration between European institutions; museums and laboratories which used the same wide range of analysis techniques in the way to have the best global view about this complex Theban production