A lthough this arresting portrait by Botticelli (fig. 1) has long been known to scholars and the public alike, only minimal technical information on the painting has ever been published. Recent examinations coinciding with its appearance on the market provide an ideal moment to consider the condition and making of the picture. The present technical study incorporates information gained from x-radiography, infrared reflectography, macro-x-ray fluorescence (XRF) scanning, Raman spectroscopy, and close examination under the microscope.1
Botticelli employed materials and techniques that were common in Florence during the second half of the fifteenth century; he was at once methodical and inspired, carefully planning his composition but making refinements as he worked. Proving that a great painting is more than the sum of its parts, this portrait demonstrates how the brilliant facility of the artist can transform mundane substances into an object of transcendent beauty and lifelike effect.
Support and ground
The support is a single piece of wood which appears to be poplar, a typical choice in Italy, with the grain oriented vertically. Botticelli seems not to have been particular in his selection of support, for the plank has two knots (fig. 2); such flaws are common in Renaissance panels, and other works by the artist (including his Portrait of a Lady known as Smeralda Bandinelli) also show imperfections and repairs.2 The panel appears to be thinned slightly; at about 16mm in depth, it is thinner than standard panels of the period. It is now trimmed slightly on all sides, perhaps to remove an original engaged frame like that still preserved on the Portrait of a Man with a Medal of Cosimo il Vecchio in the Uffizi.3 Early panels were frequently trimmed and their engaged frames, which consisted of wood moldings attached to the panel face, removed by later generations. The trimming of the panel apparently occurred in two phases: the left and top edges (seen from the front) were cleanly cut, after which a coating was applied to the reverse, while the bottom and right edges were sawn more coarsely and here the reverse coating has been planed away (fig. 3).
The front face of the panel was prepared for painting with a white gesso, traditionally composed of gypsum bound with animal glue, applied in multiple layers and smoothed to create a bright level surface. The gesso frequently shows through in transparently painted areas to create luminous accents, as in the jacket and at junctures of compositional elements. The opaque off-white coating on the back of the panel, a mixture that includes gypsum and lead white, appears to have been added after the original frame was removed, as noted above, and therefore after the painting was completed. Some restoration to this coating, dating to the nineteenth century or later given the presence of zinc white, is evident at left.4
Underdrawing and incisions
The minimal compositional indicators Botticelli set in place prior to painting suggest the layout was carefully worked out in advance. Some of the initial drawing below the paint layers can be detected using infrared reflectography (IRR), which leverages the transparency of many paints to the infrared portion of the electromagnetic spectrum to reveal underdrawing created with carbon-based materials, such as black ink and charcoal.
Other paintings by the artist show minimal, loose underdrawing in brush and ink to place major elements as simple contours, while more finely drawn lines, used to carefully indicate details such as facial features, are present but difficult to detect. In the infrared reflectogram of the present portrait, broad lines are evident to establish the chin, neck, and waist, and searchingly mark the contours of the figure’s left shoulder (fig. 4). Finer underdrawn features, sure-handed lines completed in a single pass, are occasionally visible. With IRR, they are difficult to differentiate from painted details because Botticelli later traced these contours with carbon-containing paints. However, under close examination with normal light, black underdrawn lines can be seen through the paint in areas including the right corner of the mouth, the corner of the left eye, and the lower hand (fig. 5). It is possible that Botticelli transferred the facial features from a drawing; while no clear evidence of this technique was found here, signs of tracing and pouncing have been found, for example, on his Portrait of a Lady Known as Smeralda Bandinelli.5 A notable change clearly visible in IRR is the placement of the row of buttons running down the front of the jacket, which were shifted approximately 1.5 cm to the right during the painting process (fig. 4).
Geometric elements of the composition, including the architecture and roundel, were fixed with incisions into the gesso preparatory layer (figs. 6,7). Linear incisions were created with a straightedge and metal stylus, while the aid of a compass was required for the roundel. Added after the general position of the sitter was established by underdrawing, the incisions indicate the placement of the window opening, ledge, and walls, skirting the contour of the head and body but with some overlap into the figure. Multiple overlapping arcs in the round frame seem to reflect the artist working out the slight yet spatially complicated tilt to the round frame profile, as well as a shift in its position. Such incisions are a common feature of Botticelli’s technique and have been observed in many of his works, including his Adoration of the Kings in the National Gallery, London (inv. no. NG1033).6
Painting and pentimenti
A modest selection of pigments was available to Botticelli in the Quattrocento, much the same ones that had been available to Bartolomeo Bulgarini, the painter of the gold ground tondo, a century before. Of these, Botticelli included here lead white, ochre and umber earth colors, vermilion red, lead-tin yellow, and carbon black, as well as more costly red lake. For the blue, he chose ultramarine, a vibrant and precious pigment as expensive as gold.
Once the composition was designed, thin, local areas of broad underpainting, sometimes called imprimitura, were applied. These functioned to seal the gesso, establish forms, and underpin upper layers of the tempera paint. In the face, for instance, the light underlayer shines through the transparent shadows, an updated version of the practice employed by Trecento artists and described in Cennino Cennini’s Libro dell’arte of ca. 1400. Because it contains lead white, the brushy application of the underpainting is visible in the XRF map for lead (fig. 8): this reveals the initially unresolved neckline that was later defined by the clothes, for instance, as well as the first fluid laying-in of the left hand. In other works by Botticelli, including his Portrait of a Young Man with a Mazzocchio in the Uffizi, this layer has sometimes been found to contain oil—a reminder that the new medium of oil painting was infiltrating the traditional practice of egg tempera.7
In the flesh tones, reflective highlights on the fingers and along the chin are not created with strokes of light paint at the top layer as one may expect, but are areas where the reflective imprimitura is left in reserve: Botticelli paints up to a few millimeters from the edge of the contour to leave light reflections and highlights (fig. 9). With most artists these are final touches, determined at the end of the painting process. Botticelli is in a sense working backwards, showing his mastery over his materials. In other respects, the buildup of the flesh follows a more typical system, with varying shades of vermilion and lead white-containing pink added atop the yellow-brown modelling of the forms, with red and brown earth pigments added for deeper shadows.8 The paints are applied in delicate, translucent strokes in such a way as to create a remarkable luminosity in the flesh. Final limned details, both dark and light, articulate forms and contours. The hair follows a similar method, a light underlayer refined by overlaid crisp brushstrokes, both opaque and translucent.
There is a literalness of materials in the jacket, for the purplish color employs one of the same red dyes used to tint costly fabrics during the Renaissance. Red lake pigment was mixed with black to create the garment’s dark tones, which were thinly washed in over the gesso ground, and continued in the hatched strokes that trace the volumes. Mixtures of red lake, white, and black were applied in increasingly dense, hatched scumbles to articulate mid-tones and highlights on the cloth. The cooling effect of the greyish scumbles atop the dark red paint creates the purple tone. (fig. 10) This mixture of pigments must have been a favorite of the artist, for it recurs in a range of hues, from lilac to dark purple, throughout his works.9 Along with final red-black lines for contours in the garment, some of the shadow details are in fact areas where the dark underpaint was left untouched by the light scumbles. Like the reflected highlights in the flesh, the technique is an example of how Botticelli’s skill and clarity of vision allowed him to use his materials efficiently. The jacket must have been one of the first portions of the painting to be completed, as the sky, grey architecture and white collar all overlap it.
The abstract architecture was fluidly applied in shades of gray, with no modulation to the color within a single plane, using simple mixtures of lead white and black pigments in varying proportions. In the parapet, painted around the hand, the addition of ultramarine blue lends a coolness to the grey stone. In the sky, a similarly liquid paint containing lead white and ultramarine followed the lines incised early on (figs. 11, 12).
Tempera painting has a reputation for precision as a process that requires extensive planning and discourages alterations; Botticelli’s sure-handed and economical application of paint reflects this. Although precise, the paint handling is not fussy, with remarkably lifelike results that can be difficult to achieve with the medium. At the same time, the tempera technique had grown freer and more painterly by the late-fifteenth century and many works by Botticelli, including the present picture, show changes, or pentimenti. So while Botticelli carefully planned the composition before starting to paint, the artist also exploited the opacity of lead white to make alterations as he worked: the face was refined after the hair was painted to render the neck and chin fuller, the youth’s left shoulder was adjusted, the line of buttons on the jacket was shifted rightward, and the left index finger and thumb were moved. Changes were likewise made during the incision stage, with unused marks visible for the architecture.
One significant pentimento involves the medallion: visible in IRR, the fingers of the figure’s right hand were moved outward from the tondo frame, beyond the small reserve originally left for them, and painted atop the dark architecture and jacket (figs. 4, 13). This shift suggests that the frame was shifted upward and to the left from its original position, or perhaps was originally smaller in circumference. Another major alteration is revealed clearly in the x-radiograph, where the earlier contours of the coiffure appear: the overall length was extended from a point just touching the top edge of the collar to reach the shoulders (figs. 2, 8). This adjustment took place after the sky was fluidly laid in and required a more opaque mix of pigments than in the bulk of the hair.
Botticelli devised a series of comparisons in the picture—the youthful sitter with the aged saint in the roundel, the hieratic Sienese antique with the illusionistic Florentine portrait, the styles of the Trecento and Quattrocento. The tondo frame holds another, material juxtaposition: between the literal gold of the icon and the painted frame held by the sitter, created using a base of brown containing vermilion and earth colors with shimmering glints of lead-tin yellow above. Here the real and the artificial are reversed (fig. 14a-d).
Technical study has been unable to answer perhaps the most debated question about the painting—whether or not the roundel is an original element—but it can offer some information.
The roundel itself is a fragment from a larger work, perhaps once part of an altarpiece or devotional object. Its facture is similar to that employed by Botticelli in the larger painting. The wood panel was prepared with gesso and, in this case, a reddish clay bole for water gilding. Painting was done in the fine brushstrokes of egg tempera, with final delicate highlights added to the textiles with mordant gilding, which is now worn. Analysis suggests that the saint’s robe, containing the pigment azurite, was originally bluer in color (fig. 14d).
A pinpoint loss in the beard of the saint (since restored) appears to mark the point where the center of a compass was used to delineate the new circumference. The roundel was inserted into a slightly irregular cavity in the Botticelli panel, some 8 mm deep, carved after the position of the tondo frame was incised in the gesso. The Sienese panel had already suffered worm damage, for filled woodworm channels are visible in the x-radiograph (fig.15). Thinned to about 4 mm with the edges slightly tapered, the insert was secured in the Botticelli panel through a bed of putty, perhaps gesso, of about the same thickness.10 Part of the debate about the roundel’s connection to the painting has involved this method of attachment. Previous discussion has assumed that the roundel was embedded in a paste of lead white and oil, a technique not typical to period, but this cannot be the case. In the recent x-ray of the panel, details of the saint in the roundel are visible (fig. 2). A thick layer of radiopaque lead white would completely obscure the far thinner paint layer, yet only the worm channels, the areas with the greatest density of adhesive, are revealed as radiopaque white lines.11
The Renaissance “restoration” of the Trecento roundel remains mysterious, for the material added at its edges appears to postdate the Botticelli panel. The boundaries of the old gilding are fairly rectangular, and have been extended to fill the circle; here somewhat crude punchwork seeks to integrate the newer areas with the original gold. Fill material bridges the interface between the two wood supports, possibly addressing losses that developed from the differing movements of the two pieces of wood over time. Perhaps this has been renewed in more recent times; certainly, the retouching around its edges is modern. Yet there is no sign that the roundel has ever been removed. In seeking answers for this persistent question, the principle of Occam’s razor may offer guidance: the integrity of the existing arrangement reflects the simplest solution.
Surely to some degree, however, this ambiguity is part of the allure of the picture. Understanding the materials and making of the panel, likewise, can enhance our appreciation, but Botticelli’s mastery remains the real attraction.
1. James Martin, Chief Scientific Officer, Sotheby’s carried out x-radiography, infrared reflectography (IRR, Osiris Camera / Opus Instruments), macro-x-ray fluorescence (XRF) scanning, and Raman spectroscopy on the painting. The painting was restored by Johannes Hell in the mid-twentieth century and by John Brealey at the Metropolitan Museum of Art in 1983 (after the Christie’s sale of 1982); adjustments to the varnish were carried out by David Bull in 1994 when the painting was on loan to the National Gallery of Art in Washington. DC. Written reports from the latter period provided invaluable information for this essay.
2. No original repairs or textile reinforcements of the panel are visible. On the use of imperfect supports in Italian Renaissance painting, see L. Uzielli, “Historical Overview of Panel-Making Techniques in Central Italy,” in The Structural Conservation of Panel Paintings, K. Dardes and A. Rothe (eds.), Los Angeles 1995, p. 116; for a panel by Botticelli repaired prior to painting, see N. Costaras and C. Richardson, “Botticelli’s Portrait of a Lady known as Smeralda Bandinelli: a technical study,” in Botticelli Past and Present, A. Debenedetti and C. Elam (eds.), London 2019, pp. 38–40.
3. On the engaged frame on the Uffizi portrait, see E. Buzzegoli and M. Marchi, “Botticelli: ‘Ritratto di Uomo con Medaglia’ nella Galleria degli Uffizi, Note Sul Restauro,” The Conservator 16, 1, (1992), p. 48.
4. A series of wide rectangles in this area, clearly visible in the infrared reflectogram of the reverse, suggest that three pieces of a thin material were adhered to the back of the panel in this area. This material cannot be seen from the surface.
5. See Costaras and Richardson 2019, p. 40.
6. See J. Dunkerton, S. Foister, D. Gordon, and N. Penny, Giotto to Dürer: Early Renaissance Painting in the National Gallery, London 1991, p. 312; see also J. Dunkerton, “Osservazioni sulla tecnica delle opere di Sandro Botticelli alla National Gallery di Londra,” in Il tondo di Botticelli a Piacenza, D. Gasparotto and A. Gigli (eds.), Milan 2006, p. 73; see also U. Fischer in Florentiner Malerei Alte Pinakothek: Die Gemälde des 14. bis 16. Jahrhunderts, A. Schumacher (ed.), Berlin 2017, pp. 429–30; see also Costaras and Richardson 2019, p. 40.
7. On Botticelli’s use of a pale green underpainting for flesh tones, see Dunkerton 2006, p. 70; see also C. Castelli, M. Ciatti, C. Lalli and A. Ramat, “Il restauro del ‘Ritratto di giovane con mazzocchio’ di Sandro Botticelli,” in OPD Restauro, 23 (2011), p. 144. Oil has been detected in a number of paintings by Botticelli: see Castelli et al. 2011, p. 148; see also C. Higgitt and R. White, “Analyses of Paint Media: New Studies of Italian Paintings of the Fifteenth and Sixteenth Centuries,” in National Gallery Technical Bulletin, 26, (2005), pp. 88–104. Medium analysis was not carried out on this painting.
8. A similar paint buildup is seen in Portrait of a Woman Known as Smeralda Bandinelli in the Victoria and Albert Museum.
9. Because the red-containing passages fluoresce in ultraviolet light, the pigment may be madder lake (though the fluorescence is pinkish rather than the characteristic orange). For similar mixtures including red lake in paintings by Botticelli, see J. Dunkerton and A. Roy, “The Materials of a Group of Late Fifteenth-Century Florentine Panel Paintings,” in National Gallery Technical Bulletin, 17, (1996), pp. 20–31; Costaras and Richardson 2019.
10. A report by the conservator David Bull (30 May 1991) and transverse x-radiograph made at the National Gallery, Washington (May 1991) shed light on the thickness of the roundel and revealed that it only fills about half of the depth of the cavity.
11. The x-radiograph published by Stapleford had a very high contrast and as a result the roundel could be interpreted as an area with the density of lead; see R. Stapleford, “Botticelli’s Portrait of a Young Man Holding a Trecento Medallion,” in Burlington Magazine 129, 1012 (July 1987), p. 430. However, the x-radiograph completed in 2020 is a more accurate visual representation of the relative densities of the materials involved. That the roundel appears in the XRF map of the panel reverse for the element strontium, a common component in gypsum, could suggest that the adhesive is gesso, which was found adhering the medal of Cosimo the Elder in the Uffizi portrait; see Buzzegoli and Marchi 1992, p. 50.