VIS Sample 19

This sample was collected from the pink section of the robe worn by the kneeling woman before removal of the overpaint. The red-brown ground can be seen as well as two to three layers of paint; the light yellow paint may be the underlying flesh paint of the woman's back while the uppermost pink paint corresponds to the drapery (visible light/100x magnification). The uppermost paint layer was later confirmed to be unoriginal restoration paint.

timeline view   simple view
Date: 2014-01-16

SEM Sample 1

This sample was collected from the shot-silk robe of the woman holding the tambourine after removal of the degraded surface coating. The red-brown ground contains iron oxides, calcium, and alumino-silicates (Fe, Ca, Al, Si, O, Mg, Mn) while the paint layers appear to contain iron oxides (particularly green earth; Fe, Si, Mn, O) and lead white (Pb).<br/<br/><i>Top Left: Visible light/200x magnification; Top Right: BSE image/259x magnification; Bottom left and right: EDS elemental maps (Major Elements: Si, O, Ca, Al, Pb, Fe, K; Trace: Mg, Mn, Na, Ti)<i>

timeline view   simple view
Date: 2013-12-25

SEM Sample 2

This sample was collected from the blue robe worn by the kneeling woman in the lower right corner before removal of the degraded surface coating. The red-brown ground contains iron oxides, calcium, and alumino-silicates (Fe, Ca, Al, Si, O, Mg, Mn) while the dark blue paint layer appears to contain an extremely pure grade of lapis lazuli (Al, Na, Si, O) followed by a thin layer of lapis mixed with lead white (Pb). In this particular sample the upper layer of the double ground is extremely thin and can only be detected in the EDS map for iron. A large red, iron oxide particle can also be seen in the lower left.<br/><br/><i>Top Left: Visible light/200x magnification; Top Right: BSE image/264x magnification; Bottom left and right: EDS elemental maps (Major Elements: Si, O, Ca, Al, Pb, Fe, K, Mg; Trace: Na)</i>

timeline view   simple view
Date: 2013-12-25

SEM Sample 3

This sample was collected from a heavily overpainted back of the kneeling woman in the bottom right corner. The red-brown ground contains iron oxides, calcium, and alumino-silicates (Fe, Ca, Al, Si, O, Mg, Mn) while the uppermost layer of overpaint contains Zinc White (Zn), a pigment that was not available to artists until the 19th century. Spot analysis of red and yellow pigment particles mixed into the original lead-containing paint layers confirmed the presence of vermillion (Hg) and lead-antimonate yellow, most likely Naples Yellow (Pb, Sb). Top Left: Visible light/200x magnification;<br/><br/><i>Top Right: BSE image/302x magnification; Bottom left and right: EDS elemental maps (Major Elements: Pb, O, Si, Ca, Al, Zn, Fe; Trace: K, Mg, Mn, Hg, Sb)</i>

timeline view   simple view
Date: 2013-12-25

SEM Sample 4

This sample was collected from the green-colored cushion on King Saul's throne before removal of the degraded surface coating. The red-brown ground contains iron oxides, calcium, and alumino-silicates (Fe, Ca, Al, Si, O, Mg, Mn); the upper ground layer contains more iron and manganese than the lower layer, indicating a higher concentration of earth colors/umbers in the second ground application. The presence of green earth particles was confirmed by the detection of high levels of silica (Si) and moderate to low levels of iron (Fe).<br/><br/><i>Top Left: Ultraviolet light/200x magnification; Top Right: BSE image/217x magnification; Bottom left and right: EDS elemental maps (Major Elements: Si, O, Ca, Al, Fe; Trace: K, S, Mg, Mn)</i>

timeline view   simple view
Date: 2013-12-25

SEM Sample 5

This sample was collected from Abner's yellow ptergues (leather straps worn at the waist by Roman soldiers). The red-brown ground contains iron oxides, calcium, and alumino-silicates (Fe, Ca, Al, Si, O, Mg, Mn); the upper ground layer contains more iron and manganese than the lower layer, indicating a higher concentration of earth colors/umbers in the second ground application. The upper paint layers contain lead white (Pb) and yellow iron oxides (Fe, O). Top Left: Visible light/200x magnification;<br/><br/><i>Top Right: BSE image/399x magnification; Bottom left and right: EDS elemental maps (Major Elements: Si, O, Ca, Pb, Al, Fe; Trace: K, S, Mg, Mn)</i>

timeline view   simple view
Date: 2013-12-25

SEM Sample 6

This sample was collected from the green-colored mountains in the distant background after removal of the overpaint and degraded surface coating. The red-brown ground contains iron oxides, calcium, and alumino-silicates (Fe, Ca, Al, Si, O, Mg, Mn). The paint layer contains lead white (Pb), earth colors (Fe, Si, O), and lead-antimonate (Pb, Sb). The presence of green earth particles was confirmed by the detection of high levels of silica (Si) and moderate to low levels of iron (Fe). A few yellow particles were found to contain lead and antimony (Pb, Sb) pointing towards the presence of Naples Yellow, however a large whitish agglomerate appeared to contain lead, antimony, and high levels of silica (Si). It may be that a range of lead-antimonate particles were used, with some possessing more of a "glassier" nature than others. Colored glass has been found in Italian Renaissance and Baroque paintings.<br/><br/><i>Top Left: Visible light/200x magnification; Top Right: BSE image/2124x magnification; Bottom left and right: EDS elemental maps (Major Elements: Si, O, Pb, Al, Ca, Fe; Trace: K, Mg, Sb)</i>

timeline view   simple view
Date: 2013-12-25

SEM Sample 7

The red-brown ground contains iron oxides, calcium, and alumino-silicates (Fe, Ca, Al, Si, O, Mg, Mn). Multiple paint layers were found to contain lead-antimonate yellow (Pb, Sb), lead white (Pb), and earth colors (Fe, Si, O, Mn). The presence of phosphorous in the black paint layer indicates the presence of bone black (P). Images obtained using x-radiography confirmed that these colored paint layers beneath the black most likely correspond to a hidden figure that is present beneath the shield. Top Left: Visible light/200x magnification;<br/><br/><i>Top Right: BSE image/997x magnification; Bottom left and right: EDS elemental maps (Major Elements: Si, O, Pb, Al, Ca, Fe; Trace: K, Mg, Sb)</i>

timeline view   simple view
Date: 2013-12-25

VIS Sample 20

This sample was collected from the yellow belt of the kneeling woman after removal of the overpaint and degraded varnish. The red-brown ground can be seen as well as several layers of paint; the black layer may represent dark paint used to delineate contours of the figures before successive paint layers were applied (visible light/100x magnification).

timeline view   simple view
Date: 2014-01-16

VIS Sample 21

This sample was collected from the yellow belt of the kneeling woman after removal of the overpaint and degraded varnish. The red-brown ground can be seen as well as two layers of paint; the yellow belt in this instance was painted directly over a portion of the underlying blue robe (visible light/100x magnification).

timeline view   simple view
Date: 2014-01-16

Visible/Ultraviolet Light Samples

Conservators and scientists will occasionally collect tiny microscopic <a href="http://www.artcons.udel.edu/about/kress/examination-techniques-and-scientific-terms/cross-sectional-microscopy">samples</a> from artwork in order to obtain a better understanding of the object's restoration history as well as the original materials used by the artist(s). Samples are often taken in conspicuous areas, such as near regions of existing loss or even along outer edges of a composition. In the case of the Triumph of David, there were multiple old tears and losses scattered throughout the painting allowing for the collection of several paint samples. These samples are then embedded in a clear resin and polished smooth, giving a cross-section view of the paint layers from the ground up under high magnification.<br/><br/>Samples can be viewed in visible and ultraviolet light as both types of illumination can reveal complementary information. Certain pigments may auto-fluoresce under ultraviolet light as well as certain organic materials like varnishes, glues, etc.<br/><br/>Cross-sectional samples subjected to both visible and ultraviolet illumination were prepared by Kristin deGhetaldi (project leader). Samples were imbedded in Extec(R) polyester resin/ hardener (approximately 10/ 0.5 ml) and subsequently analyzed under high magnification using a Nikon Eclipse 80i Binocular Microscope (4x, 10x, and 20x objectives) with a Nikon X-cite(R) 120 Mercury Lamp for reflected ultraviolet light. Under ultraviolet light, the samples were viewed using a BV-2A cube (excitation wavelengths between 400 and 420/ 470 nm barrier filter). Digital images were obtained using the Digital Eclipse DXM 1200f Nikon Camera in conjunction with the Automatic Camera Tamer control software for PC systems.

timeline view   simple view
Date: 2014-01-22

VIS/UV Sample 1

This sample was collected from the blue robe of the kneeling woman after removal of the degraded surface coating. The red-brown ground can be seen as well as two to three layers of blue paint containing ultramarine (lapis lazuli) with small additions of lead white (visible light/ultraviolet light/200x magnification). Ultraviolet illumination helped to reveal the presence of a double red-brown ground as well as a thin, pigmented glaze between two layers of paint.

timeline view   simple view
Date: 2014-01-22

VIS/UV Sample 2

This sample was collected from an area of the sky after removal of the degraded surface coating. The red-brown ground can be seen as well as two to three layers of blue paint containing ultramarine (lapis lazuli) with small additions of lead white (visible light/ultraviolet light/100x magnification). Ultraviolet illumination helped to reveal the presence of a double red-brown ground as well as a thin, pigmented glaze between two layers of paint (this particular area of the sky was painted using a layering system very similar to certain sections of the blue robe worn by the kneeling woman).

timeline view   simple view
Date: 2014-01-22

VIS/UV Sample 3

This sample was collected from a heavily overpainted back of the kneeling woman in the bottom right corner. by the kneeling woman after removal of the degraded surface coating. The red-brown ground can be seen as well as two to three layers of paint; the lighter paint layers correspond to the original flesh tones while the uppermost layer represents the unoriginal restoration paint (visible light/ultraviolet light/100x magnification). Ultraviolet illumination helped to reveal the presence of a double red-brown ground; the lack of strong auto-fluorescence in the uppermost layer also supported later findings that confirmed that this layer was unoriginal overpaint.

timeline view   simple view
Date: 2014-01-22

VIS/UV Sample 4

This sample was collected from Abner's yellow ptergues (leather straps worn at the waist by Roman soldiers). The red-brown ground can be seen as well as two layers of paint (visible light/ultraviolet light/100x magnification). Ultraviolet illumination helped to reveal the presence of a double red-brown ground as well as a strongly auto-fluorescent red-colored glaze beneath the yellow paint containing yellow ochre and lead white.

timeline view   simple view
Date: 2014-01-22

VIS/UV Sample 5

This sample was collected from the blue robe worn by the kneeling woman in the lower right corner before removal of the degraded surface coating. The red-brown ground can be seen as well as two layers of blue paint containing ultramarine (lapis lazuli) with small additions of lead white (visible light/ultraviolet light/100x magnification). Ultraviolet illumination helped to reveal the presence of a double red-brown ground; the bottom layer of blue paint can also be seen to contain very few contaminants indicating a higher grade of lapis lazuli was used. This thick blue layer is followed by a thinly applied layer of lapis mixed with lead white followed by the thick layer of degraded surface coating.

timeline view   simple view
Date: 2014-01-22

VIS/UV Sample 6

This sample was collected from the shot-silk robe of the woman holding the tambourine after removal of the degraded surface coating. The red-brown ground can be seen followed by two thin layers of paint rich in earth colors (particularly green earth) and lead white (visible light/ultraviolet light/100x magnification). Ultraviolet illumination helped to reveal the presence of a double red-brown ground.

timeline view   simple view
Date: 2014-01-22

VIS/UV Sample 7

This sample was collected from the soldier's red cloak near the lower left corner before the removal of the overpaint and the degraded surface coating. The red-brown ground can be seen followed by several layers of red paint, indicating that multiple adjustments were made to this area of the composition (visible light/ultraviolet light/100x magnification). Ultraviolet illumination helped to reveal the presence of a double red-brown ground while the uppermost paint layer was later confirmed to be unoriginal restoration paint; note that the overpaint is painted over the crack that runs through all of the original paint and ground layers.

timeline view   simple view
Date: 2014-01-22

VIS/UV Sample 8

This sample was collected from the arm of the standing soldier near the left edge after removal of the overpaint and the degraded surface coating. The red-brown ground can be seen followed by several layers of paint, indicating that multiple adjustments were made to this area of the composition (visible light/ultraviolet light/100x magnification). Ultraviolet illumination helped to reveal the presence of a double red-brown ground as well as darker, lower layers of paint (perhaps corresponding to the underlying tunic or darker flesh tones along the contour of the arm) followed by lighter flesh tones. Later examination with x-radiography confirmed that the soldier's arm was enlarged during a later stage of the painting process.

timeline view   simple view
Date: 2014-01-22

VIS/UV Sample 9

This sample was collected from the black shield near the lower left corner after removal of the overpaint and the degraded surface coating. The red-brown ground can be seen followed by several layers of paint, indicating that multiple adjustments were made to this area of the composition (visible light/ultraviolet light/100x magnification). Ultraviolet illumination helped to reveal the presence of a double red-brown ground as well as several colored layers of paint beneath the uppermost layer containing bone black. Later examination with x-radiography confirmed that a hidden figure is present beneath the shield.

timeline view   simple view
Date: 2014-01-22