Madder1 was known through many names across time. In antiquity it was known as erythrodanon (gr.)2 or rubia/ ereuthodanum erythtodanum3, while in the Middle Ages it had various names. Rubia is mentioned in a twelfth-century in a color recipes book called Mappae Clavicula4, Warencia, garancia, and rubea radix were mentioned by Heraclius.5 Finally, in sixteenth-century Italy, madder was known by the names robbia, roza, granzuolli,or ciocchi.6

In the preparation of the pigment, the temperature the alum is very important. It should be hot (otherwise the colour resulted will be brown), but not boiling; also, if too much is used, the color will turn out dull (the ideal proportions should be one part madder and one part alum).7

Under UV light madder will appear orange, cochineal and kermes carmine bright pink, while alizarin and lac lakes should display no fluorescence.8

1 Rubia tinctorum L. and various other plants from the rubiaceae family (Artists’ pigments, vol. 3, p.109)2 Blümer,19123 Artists’ pigments, vol. 3, p. 109.4 T. Philips, ‘’Mappae Clavicula – A treatise on the Preparation of Pigmenta during the Middle Ages,’’ Archaeologia 32 (1847), pp. 183-244.5 A. Ilg, Quellenschiften für Kunstgeschichte und Kusttechnik des Mittelaters und der Ranaissance, Viena, 1873, apud Artist’s Pigments, vol 3, p. 111.6 G. Rosetti, The Plichto of Gioanventura Rosetti (Instructions in the art of the dyers which teaches the dyeing of woollen cloths, linens, cottons, and silk by the great art as well as by the common, Cambridge, Mass. and London 1969, apud Artists’ Pigments, p.111.7 Artists’ pigments, vol. 3, p. 122.8 Artists’ pigments, vol. 3, p. 124.

Sample Brina3, taken from sdfsdfsdfsfs contains a similar red lake [spectrum 15, fig.] to the ones from Brina1, showing all the elements mentioned (including phosphorus), and a orange fluorescence, which could be an indicatior of madder. It is mixed in the blue layer, with lead white, smalt and a black organic pigment.

Smalt can be identified int his sample as well [spectrum 13]. Smalt is basically a potassium glass of blue color (due to adding cobalt oxide during the manufacturing process) and it’s presence here can be identified mainly due to the high peaks of silicon (and other elements present in glass: Na, Al,

Fe),9 oxigen, potassium and cobalt, as well as arsenic.10 Beckmann11 and Meltzer12 support the idea that it was invented somewhere between 1540-1560, but it was probably available much earlier, since it was found in at least two paintings of the fifteenth-century (1. Dieric Bouts The Entombment, National Gallery, London, No. 664 – mixed with azurite and ultramarine in Nicodemus’s collar; glue tempera medium: Fig. / 2. Michael Pacher, The Early Fathers, altar, Bayerische Staaatsgemäldesammlungen, Munich, 25097-2600: Fig.).13 According to Gettens and Stout14 and Harley15, smalt was most probably discovered in the Near East a few centuries before, and it may have derrived from the process of producing vitreous enamel, which is fairly similar and some of the terminology seems to confirm it as well (Bleu d’émail, and esmalte).16

The rest of the spectra from the blue layer (5) of Brina3 appear with a similar composition, but more pale or discoloured.

Because it is a glass, smalt is transparent and its hiding power is low, which means it must be coarsely ground to be used as a pigment.17 This corresponds to the particle we see in Brina3, which is comparably larger than most of the other particles. The colour of the layer containing this smalt particle (layer 5 – fig.) is fairly fade. This might have been intentional or it may be due a discoloration in time, if the medium is oil. The presence of lead might have reduced the discoloration phenomenon, which is normally best avoided if the media is aquaeus and lime (fresco).18 Plesters19 observed this discoloration occurence in several paintings in the National Gallery: The Adoration of the Shepherds by Esteban Murillo (has smalt in the shepherd’s jerkin [fig.]); the skies in Paolo Veronese’s series of four Allegories etc.

A number of factors may be responsible for this phenomenon. Because the low refractive index (c. 1.46-1.55) is close to that of fresh linseed oil (c. 1.48), aging causes the index of the oil to increase while the smalt’s capacity to scatter light decreases; basically if the paint medium is discoloured and darkened, that affects the appearance of smalt, which, as a coloured glass, does not have a high tinting strength. On another hand, being a potash glass, smalt has generally a lower stability than soda glass and if it also contains excess alkali, when exposed to atmospheric moisture, it will leach out into the paint medium and will generate yellow or brown saponification products of the oil, which again temper with the general colour. Lastly, migration of the cobalt ions from the smalt into the medium would also be a reason for discolouration.20

9 Marika Spring, Appendix of ‘Colourless Powdered Glass as an Additive in Fifteenth- and Sixteenth- Century European Paintings,’ National Gallery Technical Bulletin, vol. 33, 2012, pp. 20-23.10 Artists’ Pigments, vol.2, p. 113- 115.11 J. Beckmann, A History of Inventions, Discoveries and Origins, 4th ed., vol. 1 London 1846, 48312 C. Meltzer, Berklaüftige Beschreibung der Churfürstl. Säüchsischen Berkstadt Schneebergh, Saxony 1684, cited by Artists‘ pigments, p. 144.13 Artists’ pigments, vol. 2, p. 114.14 R. J. Gettens and G. L. Stout, Painting Materials – A short Encyclopedia, New York 1966 157-159.15 R. D. Harley, Atists’ pigments c.1600-1835, 2nd ed. London 1982, 53-56.16 Aritsts’ pigments, vol. 2, p.114.17 Artists’ pigments, vol. 2, p. 115.18 Artists’ pigments, vol. 2, p. 116.19 J. Plesters, “Cross-sections and Chemical Analysis of Paint Samples,” Studies in Conservation 2 (1955-1956), pp. 110-157.20 J. Plesters, “A preliminary Note on the Incidence of Discoloration of Smalt in Oil Media,” Studies in Conservation 14 (1969), pp. 62-74.

Underneath the blue layer there is a yellow mixture of chalk (calcite with particles of dolomite mainly), a black organic pigment and a yellow lead-containing pigment: (massicot).21

Massicot, here in the form of lead monoxide (PbO), had different meanings throughout time. The main source of confusion was the term giallolino, of Italian origins, which may have been used for both lead monoxide and lead-tin yellow.22 While in practice the difference is quite obvious from their names, the literature has been unintentionally deceiving, due to the lack of standardisation. Most probably, massicot was used to roughly determine a colour, not its exact components,23 but it is currently identified as PbO,24 as opposed to lead-tin yellow or lead antimonate.

Dolomite is a colourless calcium magnesium carbonate mineral ([CaMg][CO3]2). Hall (1973)25 describes dolomite as 40-44% magnesium carbonate and 54-58% calcium carbonate. As a common component of limestones and some marbles, dolomite may easily be incorporated into lake pigments containing crushed limestones. Ethimologically, the term comes from the Dolomite region in the Italian Alps, but it was tratitionally known as pearl spear.26 It has been also encountered in [approx. contemporary] paintings by Titian, such as The Holy Family with a Shepherd (a sample from the trees at the right of the painting – fig.98)27; Portrait of Gerolamo (?) Barbarigo (‘The Man with a Quilted Sleeve’);28 Portrait of a Lady (‘La Schiavona’)- where is found in the ground layer and imprimatura;29 Noli me Tangere – ground layer, as well as in the warm grey sky tinted with a little dolomite-containing yellow earth.30 We thus notice that, at least in these examples as well as the Brina sample, dolomite was mainly used in yellow under-layers, imprimaturae or grounds.

Fig.98 NG 4, paint cross-section from the brown foliage.31

21 Report II SEM EDX NTS Brina, p. 27.22 Artists’ Pigments, vol. 2, p. 83.23 R. D. Harley, Atists’ pigments c.1600-1835, 2nd ed. London 1982, 95-98.24 Artists’ Pigments, vol. 2, p. 85.25 R.F. Hall, ‘Calcium Carbonate, Natural’, Pigment Handbook I Patton, T.C. (ed) John Wiley, New York, 1973, pp. 419-427.26 Eastaugh, Nicholas, Valentine Walsh, Tracey Chaplin, and Ruth Siddall. Pigment compendium: a dictionary of historical pigments. Routledge, 2007, p. 148.27 Jill Dunkerton and Marika Spring, with contributions from Rachel Billinge, Kamilla Kalinina, Rachel Morrison, Gabriella Macaro, David Peggie and Ashok Roy, “Titian’s Painting Technique before 1540,” National Gallery Technical Bulletin, vol. 34, 2013, p. 51.28 Jill Dunkerton and Marika Spring, with contributions from Rachel Billinge, Kamilla Kalinina, Rachel Morrison, Gabriella Macaro, David Peggie and Ashok Roy, “Titian’s Painting Technique before 1540,” National Gallery Technical Bulletin, vol. 34, 2013, p. 54.29 Ibidem, p. 61.30 Ibidem, p. 61.31 Jill Dunkerton and Marika Spring, with contributions from Rachel Billinge, Kamilla Kalinina, Rachel Morrison, Gabriella Macaro, David Peggie and Ashok Roy, “Titian’s Painting Technique before 1540,” National Gallery Technical Bulletin, vol. 34, 2013, p. 51.

Layer 2 is a thin red layer containing an iron oxide pigment that was probably applied as an imprimatura, since is present in other layers as well (see samples Brina8 –Fig., Brina 11) followed by a thin size layer and the yellowish-white ground, which is composed of calcium sulphate (‘quite heterogeneous particle sizes suggest possibly another modification of calcium sulphate than gypsum CaSO4·2H2O, which normally has elongated, often prismatic or needle-like crystals’).32 Spectra 27 and 28 [fig.] show quite a simple composition: O, Ca, S, C, Si (spectrum 27 also shows Br in a slightly larger amount than Si) does that mean anything?

32 Report SEM EDX NTS Brina, p. 27.