The painting is on a canvas support, probably made from a bast fiber such as linen. It is a plain weave fabric and the thread count, according to automated thread count software, consists of an average of 12.84 vertical threads/cm and 14.09 horizontal threads/cm. Cusping of the canvas, caused by the original stretching of the canvas onto a strainer, is visible along all four edges in the x-radiograph (see fig. 1 above). Preparation:
The canvas is primed with a gray/brown ground, which contains coarse-grained lead white and quartz, as well as black, brown, red, and yellow particles, the latter three of which are most likely iron earth pigments (fig. 2). The ground also contains zinc, though this is a trace component.Paint Layers:
No evidence was found to indicate whether Schalcken made an initial sketch or drawing on top of the gray/brown ground. It is clear, however, that the artist thoroughly worked out his design ahead of time, as there is no evidence of changes to the composition during the painting process.
Schalcken painted the scene’s wooded setting over the gray/brown ground using thin and relatively loose brushwork, and he used the dark-colored ground to fill in the forest canopy by leaving it visible between many of the leaves and branches in the trees. To paint the green foliage, Schalcken mixed the costly pigment ultramarine blue with an organic yellow lake pigment (fig. 3). In contrast to the thinly painted background, the figures were painted more robustly, with Schalcken using a substantial proportion of lead white to provide body to the paint in these areas. Still, the figures are painted smoothly for the most part, with the artist blending brushstrokes together to produce flawlessly modeled surfaces. Schalcken did add touches of texture in the tassel and textiles that are worn by Procris. For the tassel, Schalcken dabbed relatively thick, bright highlights on top of the darker shades of brown to make the tassel appear to shimmer in the light. In the blue silk damask, on the other hand, the texturing was done first in a light blue or white paint, and the final blue layer, probably also ultramarine, was glazed on top to achieve the sumptuous blue hue. Schalcken made use of two different blue pigments in this painting, mixing smalt—a cheaper alternative to ultramarine—into the small patch of sky at the top of the composition (fig. 4). He also used the common red-orange pigment, vermilion (fig. 5), to paint the lighter passages of Procris’s red dress and the blood in her wound and, sparingly, to warm up the highlights of the brown fabric wrapped around her. He did not, however, use this brightly colored pigment in the bloodied spear tip or in the shadows of the red dress, utilizing more subdued red iron earth pigments instead (fig. 6).Condition:
This painting is in excellent condition. There are a few small paint losses associated with two small tears in the canvas support, which are located near the top of the painting, and the tacking edges of the original canvas, which is lined, were removed in the past. The wound on Procris’s chest and the drool dribbling from her mouth were also previously covered by a restorer’s overpaint, which was most likely applied during the second half of the nineteenth century (fig. 7). The removal of this later addition during a 2019 conservation treatment has restored Schalcken’s original composition.
The dark wooded surroundings have become darker over time, as the increased transparency of the oil paint in these thinly painted passages has given greater visual prominence to the dark ground below. Some of the pigments, too, have faded or become discolored. Notoriously unstable organic yellow lake pigment, which is mixed into the green foliage, has faded leaving the leaves with a bluish appearance (fig. 8). Some unfaded yellow lake pigment can be found in an area of vegetation on the forest floor, where a layer of brown paint has protected this translucent yellow pigment from the light (fig. 9). Smalt is another unstable pigment: it is known to change from a brilliant blue to a muddy brown over time. In this painting, the smalt is mixed with lead white and various other pigments, and although the smalt particles do appear discolored (fig. 8), it is unclear to what extent this discoloration has affected the overall hue of the sky.
Gerrit Albertson 2019
 The presence of yellow lake, which is difficult to identify in oil paintings, was inferred in this case by the presence of chalk (calcite) particles, a material that was commonly used as an inorganic base for organic colorants.
 Increased transparency of oil paint can be attributed to both changes in the refractive index of the oil binder, as well as the formation of metal soaps. For more on metal soaps in art, please see Investigating the Formation and Structure of Lead Soaps in Traditional Oil Paintings