Raman and Fourier transform infrared microspectroscopies reveal medieval Hispano–Muslim wood painting techniques and provide new insights into red lead production technology

Abstract

This paper describes the study of two Nasrid polychrome wooden ceilings from the Alhambra monumental ensemble using vibrational spectroscopic techniques. The study is focused on the identification of the constituent materials and execution techniques used employing non‐invasive and non‐destructive scientific investigation methods. Information about both inorganic (pigments) and organic (binders and coatings) materials has been obtained without the need for time‐consuming procedures. A complex stratigraphy involving the use of a protective priming layer of red lead covered with animal glue and white lead was revealed. The identification of Raman signatures of different lead oxide compounds, including lead‐tin oxide (Pb2SnO4), in the priming layer, allowed us to hypothesize the synthesis of red lead (Pb3O4) from litharge (α‐PbO), a common by‐product of the cupellation process used since antiquity for silver production. Furthermore, the pigments employed in hidden drawings found in the reverse of the wood pieces of one of the ceilings were also studied and compared with those found in the visible external face.

In situ Raman spectroscopy for cultural heritage studies

“…Concerning the Alhambra complex, portable Raman spectroscopy has been used alone [143] or in combination with other techniques, [144][145][146][147] to analyse plasterworks and gildings of the Hall of the Kings, marble capitals of columns of the five sites located in the complex, pigmented wooden ceilings.…”

Pigments—Lead-based whites, reds, yellows and oranges and their alteration phases

“…In the cases where litharge has been identified with certainty, it appears decidedly rarer than massicot. Based on data from the literature (see Supplementary Appendix 1), it is possible to list five (perhaps six) occurrences, in which it was (a) sometimes associated with massicot, as well as lead white and red lead; (b) found in paintings ranging from the 11 th to the 19 th century in Europe and India; and (c) present on all types of common supports, such as wood ceilings, miniature paintings, manuscripts, wall frescoes, wooden panels and eggtempera icons (Burgio et al 1999;Edwards et al 2001;López Cruz et al 2011;Ravindran et al 2011;Amadori et al 2016;Stanzani et al 2016;Arjonilla et al 2019a;Serafima et al 2019b).…”

“…associated with both lead white and red lead (9 cases), red lead (6), plattnerite (4), lead-tin yellow type I (3), scrutinyite (3), anglesite (2), galena (2), lead white (2), litharge (2), PbMg(CO 3 ) 2 (2) and chrome orange and yellow (1): found in paintings ranging from the 1 st to the 19 th century, in Europe, India and Iran: present on all types of common supports, such as wood ceilings, glass icon as (fatty tempera), illuminated manuscripts and wall paintings (fresco and secco), as well as in powdered raw pigments and wood cupboards (Burgio et al 1999;Bruni et al 2002;Smith and Clark 2002a;Castro et al 2008;Kotulanová et al 2009;Aliatis et al 2010;Ravindran et al 2011;Hradil et al 2013;Lukačević et al 2013;Duran et al 2014;Bratu et al 2015;Holakooei and Karimy 2015;Felix et al 2018;Kantoglu et al 2018;Vanmeert et al 2018;Arjonilla et al 2019a;Khramchenkova et al 2019;Costantini et al 2020b;Fioretti et al 2020).…”

“…In the literature published after their work, this pigment has been found in the following: & 12 th -to 13 th (? )-century polychrome sculptures in the porch of the main and south portals of Ferrara cathedral (Pinna et al 2020); & 14 t h -century wood ceilings of the Hall of the Abencerrages and the Hall of the Two Sisters in the Alhambra at Granada (Arjonilla et al 2019a); & 14 th -century (third quarter) wall paintings of the Dominican Monastery at Ptuj in Slovenia (Gutman et al 2014) & 15 th (also 16 th ? )-century manuscripts on parchment (for the 15 th century, see, e.g., Chaplin et al 2005;Duran et al 2014;Bonizzoni et al 2016;Carvalho et al 2018; for a 15 th /16 th -century parchment see Vanmeert et al 2018); & 15 th -to 17 th -century panel paintings on wood or walnut (for the 15 th century, see, e.g., Duval 1990, 1998;Dunkerton and Roy, 1996;Hradil et al 2007;Bersani et al 2008;Ricci et al 2004;Sodo et al 2019;Gutman Rieppi et al 2020; for the 16 th century, see, e.g., Penny et al 1996;Higgitt et al 2003;Roy et al 2004;Mottin and Laval 2004;Plazzotta et al 2006 (doubtful); Borgia et al 2007;Hradil et al 2007;Dunkerton and Howard 2009;Amadori et al 2016;Želinska et al 2018; for the 17 th century, see, e.g., Roy 1999; Olszewska-Świetlik et al 2013); & 14 th -to 17 th -century wall paintings (for the 14 th and 15 th centuries, see, e.g., Perardi et al 2003;Gutman et al 2014;Arjonilla et al 2019a;Levstik et al 2019;Pinna et al 2020; for the 17 th century, see, e.g., Vlachou-Mogire et al 2020); & 17 th -and 18 th -century oil paintings on canvas (Feller 1973;…”

Recent advances in linear and nonlinear Raman spectroscopy. Part XIV

“…Raman microscopy was hereby used for the first time for this purpose. Arjonilla et al [ 139 ] used Raman and FTIR microspectroscopies to reveal medieval Hispano–Muslim wood painting techniques and provide new insights into red lead production technology. Burgio et al [ 140 ] studied orange for gold by the use of arsenic sulfide glass in the Leman Album at the Victoria and Albert Museum.…”