The housing conditions and the materials of a collection of pastels from José Malhoa and their implication on its conservation condition

Abstract

A group of eleven pastel portraits from the painter José Malhoa (1855-1933) is presented in this paper. Some years ago they were in excellent conservation condition although having been subjected to permanent exhibition for over 30 years in a non conditioned environment. Since then their mounting conditions suffered alterations and their conservation showed signs of degradation. The storage condition history and the evolution of the pastel degradation was carefully reconstructed as well as was identified the material constituents of the pastel portraits, their pigments, bindings and support materials. It was concluded that the glass encapsulation was the main reason for the welfare of the collection and that the type of mounting and housing is more important than the presence or not of moderate exposure to indoor light. No direct relationship was found between the paper composition and the alterations.

Keywords

• Pastel
• Flocked paper
• Pigment light stability
• Glass encapsulation