The white of the 20th century: an explorative survey into Dutch modern art collections

Abstract

White pigments were abundantly used in 20th century paintings, and relate to several degradation risks such as titanium white mediated photocatalytic binder degradation or zinc soap formation. Knowledge about the white pigments that were used is essential for risk assessments of 20th century collections. In this study, a representative set of 179 paintings in Dutch modern art collections were analyzed by portable X-ray fluorescence spectrometry. Subsequent explorative data analysis was performed, supported by qualitative findings from 140 home-made reference samples. Micro-samples were further investigated by X-ray diffraction and scanning transmission electron microscopy to gain information about crystal structure and surface coating. This study reveals that Dutch 20th century artists were hesitant to use titanium white. In the Netherlands, the use of this pigment is observed convincingly from the 1970s onward and initially mostly in non-oil binders. Additionally, lead white was used until late in the 20th century for paints and grounds but rarely mixed with titanium white in paints. The study also indicated that many CoBrA artists used zinc white, underlining the risk of degradation due to soap formation. Furthermore, this study highlights the different production processes of titanium white. Through the association of titanium with niobium, an impurity only present for sulfate processed pigments, the production process can be identified. The absence of niobium indicates the presence of rutile and is thus a sign of paint stability, as well as a 'post 1959' dating. This explorative study illustrates the value of a combination of data analysis approaches, which includes assessment of spectra as well as descriptive, bivariate and multivariate analysis, for medium-sized datasets gathered at similar conditions.

Beyond the connoisseurship approach: creating a chronology in Hokusai prints using non-invasive techniques and multivariate data analysis

“…PCA is a data reduction technique which allows for an easier visualization and understanding of a complex dataset. This technique has been successfully used in the field of cultural heritage [28][29][30][31]. PCA plots are divided in four quadrants, which will express how the variables are correlated.…”

Raman Spectroscopic Analysis of an Early 20th Century English Painted Organ Case by Temple Moore

“…However, the use of earth pigments such as calcite for the whites and creams is more unusual and Thomas may have been aiming for a specific tonal effect rather than trying to save on cost, e.g., by using these low-cost pigments as extenders [59]. Alternatively Moore and Thomas may well have been aware of the toxicity of lead-based pigments (on an organ case that would be subject to regular handling) and/or the risks of degradation of synthetic additions [60] and thus preferred to use a simple, earth pigment. The availability of these pigments throughout history has been commonplace [61], therefore it would have been an easy pigment to obtain.…”

Unveiling the mural painting art of Almada Negreiros at the Maritime Stations of Alcântara (Lisbon): diagnosis research of paint layers as a guide for its future conservation

“…This is consistent with the lack of paint layer cohesion previously mentioned. On the other hand, the presence of barium sulphate, identified in the samples P3B_5 and P6A_15, can likely be associated to the pigments themselves, as this compound was frequently added as a filler by pigment manufacturers (Lähteenmäki 2009;Driel et al 2016).…”