O branco de chumbo usado por Amadeo de Souza-Cardoso e a sua alteração

A seguinte tese de mestrado acabou de ser colocada na internet:

Marta Gonçalves Félix de Oliveira Campos, The Study of Lead White Oil Paints. A Molecular Approach to the Whites of Amadeo de Souza-Cardoso, Lisboa, Faculdade de Ciências e Tecnologia, 2010.

Está livremente disponível aqui.

Resumo:

The present dissertation focuses on the study of lead white oil paints, relying on a multi-analytical approach to characterize their components, how they relate to its degradation and to assess the issue of identification of such components in real paint samples.

Having one of the most critically acclaimed Portuguese painters as a starting point, previous studies of Amadeo de Souza-Cardoso works stressed the advanced degradation observed in his lead white oil paints. Based on state of the art research in the characterization of lipidic binding media, sets of lead white oil paints were manufactured according to 19th century recipes, aiming for historical accuracy. These reconstructions were then used as reference samples to follow up the aging of the oil matrix, using micro-Fourier transformed infrared spectroscopy (µ-FTIR), and to characterize the pigment based on the consequences that its manufacturing processes have had on its properties and morphology, by environmental scanning electron microscopy (ESEM).

A chemometric approach to the FTIR results, using principal component analysis (PCA), is applied to look further into the spectral data and reach new grounds in the differentiation of the type of oil in the paint, focussing on the most important drying oils - linseed and poppy seed.

A constant concern in oil paintings is the colour changes they undergo through age, which may be due to many factors. As a side study, and using the oil paint reconstructions made, a colourimetric follow up of the influence of light and darkness offers an insight to what can be done to revert this effect without any direct action on the paint surface.