Material Analysis

Material analysis was carried out in collaboration with conservation scientists from Harvard University 's Straus Center for Conservation. Techniques included x-radiography, x-ray fluorescence, scanning electron microscopy and polarized light microscopy.

An x-radiograph was taken of two of the figurines, a male and a female, to examine the structural components and manufacturing techniques and to evaluate the condition of the underlying structure.

The x-radiograph revealed that the figurines are attached to wood bases with a wood peg and that the figures themselves appear to have been carved from one piece of wood. It also indicated that the hands of the male figure are composed of metal. Layers of gesso (calcium sulfate) were applied over the wood form to create the detailed relief of the facial features, folds of clothing, arms, legs, feet and ornaments. The surfaces were then carefully painted in a palette of red, white, black, green, brown, and flesh tone colors. All have inset glass eyes

Image of X-radiograph of male and female figurines

Analysis of several pigments was carried out using X-ray fluorescence, polarized light microscopy and scanning electron microscopy.

Identified in a cross section of the flesh tone paint layer were charcoal, red ochre, lead white and calcium sulfate.

Cross section of flesh tone paint layer (roll over image to see material locations)

A sample taken from the red trim on one of the male figurines was identified as cinnabar or dry vermilion.

Scientist taking a sample of red paint

Image of sample in cross polars

The blue pigment was Prussian blue (discovered c. 1710) and one green pigment was identified to be from the copper arsentite group that is associated with the historical pigment Scheele's green (first findings published in 1778).

The pigment analysis allowed us to narrow down the date of manufacture to between 1778 and its believed acquisition date of 1816. The identification of these historic pigments is consistent with those used in Peruvian paintings from the Colonial Period. Finally, X-ray fluorescence indicated that the metal hands were cast from lead tin alloy and then painted.