On the Two Working Palettes of Almada Negreiros at DN Building in Lisbon (1939–1940): First Analytical Approach and Insight on the Use of Cd Based Pigments

Milene Gil,Antonio Candeias,Ana Cardoso,Mafalda Costa,Sara Valadas,Sriradha Bhattacharya,Yigit Helvaci,Patricia Moita

doi:10.3390/heritage4040252

Abstract

This paper reports the first analytical approach carried out on two working palettes by Portuguese modernist master Almada Negreiros, found in 1991 behind old wood cabinets at the DN building in Lisbon. This is the only known occasion Almada left behind the color experiments done before starting to paint in the nearby walls and as such, it is a unique opportunity to analyze the materials and painting techniques that were originally used. The analytical setup comprised in loco technical photography in Vis, UVF and NIR; p-OM, spectrophotometry in Vis and h-EDXRF, complemented by OM-Vis, µ-FT-IR and VP-SEM-EDS of painting micro-samples and pigments in powder form. Preliminary results suggested the use of fresco painting technique and revealed some technical details, such as the use of a coarse lime sand finishing mortar mixed with natural vegetable fibers, and the extensive use of cadmium-based pigments that were not commonly used (or even recommended) in an alkaline environment. The Cd pigments were used alone or in mixtures with Fe based pigments in the warm hues and with cobalt and ultramarine blue pigments in some green paint layers. No clear evidence of organic materials that could have been used as binders was detected.

Highlights

Almada Negreiros (1893–1970) is a key figure of the first generation of Portuguese Modernists
In turn OM and scanning electron microscope (SEM)-energy dispersive spectrometer (EDS) analyses of a paint layer cross section (B10) indicate that calcite corresponds mainly to the binder phase whereas the silicate phases described above are present as aggregates (Figure 3b,c)
This paper unveils for the first time the pigments used by Almada Negreiros in two working palettes left on the wall of the DN building and uncovered in 1991 during restoration works

Summary

Introduction

Almada Negreiros (1893–1970) is a key figure of the first generation of Portuguese Modernists. The mural paintings of Almada Negreiros, executed between 1939–1940 at the DN building located in the heart of Lisbon, are the second public commission made by the artist and they are recognized today for their value in modern art historiography [2]. X-ray Diffraction (μ-XRD) A Bruker D8 Discover® diffractometer using Cu Kα radiation was employed to identify the main mineralogical phases of the pictorial support This analysis was carried out in one mortar sample collected right below the paint layers from palette B during the restoration works in 1991. Variable Pressure Scanning Electron Microscopy (SEM-EDS) Variable pressure scanning electron microscope (SEM) coupled with an energy dispersive spectrometer (EDS) enabled high resolution images of the cross sections and to map the elemental composition of the mortar and paint layers to complement h-EDXRF results. SEM was coupled with Bruker XFlash 5010 Silicon Drift Detector (SDD) with resolution of 129 eV at Mn Kα

Results and Discussion

Other Hues Obtained with Cadmium Pigments

Conclusions

José de Almada Negreiros