Technical Report

Technical Summary

Claude Monet’s Stacks of Wheat (End of Summer) was painted on a non-standard-size, [glossary:pre-primed] linen [glossary:canvas]. The [glossary:ground] consists of a single, off-white layer. A [glossary:warp-thread match] was detected with seven other Monet paintings from the Art Institute's collection: The Petite Creuse River (cat. 25 [W1231], inv. 1922.432); Stacks of Wheat (End of Day, Autumn) (cat. 28 [W1270], inv. 1933.444); Stacks of Wheat (Sunset, Snow Effect) (cat. 29 [W1278], inv. 1922.431); Stack of Wheat (Thaw, Sunset) (cat. 32 [W1284], inv. 1983.166), Sandvika, Norway (cat. 34 [W1397], inv. 1961.790); Branch of the Seine near Giverny (Mist) (cat. 36 [W1475], inv. 1933.1156); and Water Lily Pond (cat. 37 [W1628], inv. 1933.441), suggesting that the fabric for these paintings came from the same bolt of material.3 The painting has a rich and varied surface texture. This includes areas of open brushwork where thick strokes of [glossary:impasto] are juxtaposed with very thinly painted passages that leave the ground and canvas texture visible. Other areas consist of more fluid paint applications that appear to have been modified by the artist through the addition of extra medium to the tube paint. Final touches to the painting include brushstrokes lightly dragged across the surface, which emphasize the texture of the layers below. This includes the yellow and orange strokes used to indicate the foliage in the distant trees. For the most part, the composition was built up with little deviation from the initial [glossary:lay-in]. It appears that only the large stack at right was slightly modified during the painting process by extending the top and sides over the landscape. Some adjustments may also have been made to the horizon on the right side of the painting.4

Multilayer Interactive Image Viewer

The multilayer interactive image viewer is designed to facilitate the viewer’s exploration and comparison of the technical images (fig. 27.1).5

Signature

Signed and dated: Claude Monet 91 (lower left, in orange-red paint6) (fig. 27.2). The signature was applied when the underlying paint layers were already dry. The paint from some of the taller letters (Cl, d, and M) has been smudged to the left (fig. 27.3).

Structure and Technique

Support

Canvas

Flax (commonly known as linen).7

Standard format

The dimensions do not correspond to a standard-size [glossary:stretcher]; the stretcher was probably custom-ordered.8

Weave

[glossary:Plain weave]. Average [glossary:thread count] (standard deviation): 23.4V (0.6) × 22.6H (0.7) threads/cm; the vertical threads were determined to correspond to the warp and the horizontal threads to the weft.9 A warp-thread match was determined with seven other Monet paintings in the Art Institute's collection: The Petite Creuse River (cat. 25 [W1231], inv. 1922.432); Stacks of Wheat (End of Day, Autumn) (cat. 28 [W1270], inv. 1933.444); Stacks of Wheat (Sunset, Snow Effect) (cat. 29 [W1278], inv. 1922.431); Stack of Wheat (Thaw, Sunset); (cat. 32 [W1284], inv. 1983.166); Sandvika, Norway (cat. 34 [W1397], inv. 1961.790); Branch of the Seine near Giverny (Mist) (cat. 36 [W1475], inv. 1933.1156); and Water Lily Pond (cat. 37 [W1628], inv. 1933.441).10

Canvas characteristics

There is pronounced [glossary:cusping] along the right edge, moderate cusping on the left edge, and mild cusping along the top and bottom edges.11

Stretching

Current stretching: Dates to the lining applied prior to acquisition of the painting in 1985 (see Conservation History); copper tacks spaced approximately 2–3 cm apart. Another series of empty holes, which correspond to holes in the current stretcher, appears to be more recent.

Original stretching: Tack holes spaced 5–8 cm apart; these holes appear to correspond to the cusping pattern in the canvas on the left, top, and bottom [glossary:tacking edges], but not on the right tacking edge where the cusping is wider and more irregular.12 There are a few additional holes, located on or close to the top and bottom foldovers (there are approximately four holes on each edge, fairly regularly spaced along the length of each side).13 The origin and purpose of the holes are not known.

Stretcher/strainer

Current stretcher: Five-membered wooden expansion bolt stretcher. The top member is slightly bowed. Depth: 3.2 cm.

Original stretcher: Discarded, not documented. Depth: A second crease observed in places on the tacking margin (presumably where excess canvas was folded over the back edge of the original stretcher) suggests that the original stretcher depth was approximately 1.5–2 cm.

Manufacturer’s/supplier’s marks

None observed in current examination or documented in previous examinations.

Preparatory Layers

Sizing

Not determined (probably glue).14

Ground application/texture

The ground layer extends to the edges of all [glossary:tacking margins], indicating that the canvas was cut from a larger piece of primed fabric, which was probably commercially prepared. The ground consists of a single layer that ranges from approximately 10 to 100 µm in thickness, with the layer thicker in the interstices of the canvas and much thinner on the tops of the canvas threads. (fig. 27.4)

Color

Off-white. Some dark pigment particles were observed under magnification (fig. 27.5).

Materials/composition

Analysis indicates the presence of the following components: lead white and calcium carbonate (chalk)15, with traces of bone black, iron oxide, alumina, silica, and various silicates.16 Binder: [glossary:Oil] (estimated).

Compositional Planning/Underdrawing/Painted Sketch

Extent/character

No [glossary:underdrawing] was observed with [glossary:infrared reflectography] (IRR) or microscopic examination.

Paint Layer

Application/technique and artist’s revisions

The composition was laid in using strokes of thinly applied paint in more subdued colors than those used in the surface layers. For the small stack at left, the first application of thin reddish-brown paint, which barely covers the ground layer and leaves the canvas texture visible, can be seen occasionally through breaks in the upper brushwork (fig. 27.6). The hills in the background appear to have been laid in with shades that range from pale bluish-gray to greenish-gray. In the sky, warm off-white and gray tones were predominantly used for the initial painting. There is no overall [glossary:underpainting] in the field where the stacks are located; rather, this area consists of a buildup of individual strokes in a variety of pale hues (fig. 27.7). In localized areas, such as the long bluish-gray shadow extending from the base of the large stack, broader applications of thin, more uniform color were applied over the ground layer; in this case, a pale bluish-gray tone (fig. 27.8). In both the sky and the foreground, the earliest paint layers often consist of more textural brushstrokes with the ridges of the brush marks remaining visible through subsequent paint applications. The initial lay-in of the composition was left somewhat sketchy, with small areas of exposed ground visible throughout the canvas (fig. 27.9). The artist appears to have worked up the painting as a whole, moving back and forth between different areas of the composition.

The basic size and placement of the two stacks was laid out early in the painting process. At the upper right edge of the small stack, just below the thick orange outlining stroke that was applied later in the painting process, exposed ground is visible at the juncture between the stack and the surrounding landscape, indicating that the wheat stack and the distant landscape were built up simultaneously (fig. 27.10). In the large stack at right, on the other hand, a dense buildup of paint in a broad band around the sides and top suggests that the stack’s dimensions were increased as the painting was worked up, making the stack in the final painting significantly larger than its initial lay-in (fig. 27.11). The surface paint layers around the edges of the large stack consist of a more continuous buildup of [glossary:wet-in-wet] paint application (fig. 27.12), quite different from the more open network of superimposed brushstrokes used in the center of the stack and extensively throughout the composition (fig. 27.13). The continuous buildup of paint around the edges of the large stack makes it difficult to see the underlying layers; however, at the very edges, where there are breaks in some of the final brushwork, it is clear that the landscape continues underneath the edge of the stack to some extent (fig. 27.14).

Small areas of exposed ground visible intermittently along the upper limits of the distant hills suggest that the general horizon line was established early on (fig. 27.15). On the right side of the large stack, there is an area of densely built-up paint on and above the horizon line, which may indicate that some adjustments were made there (fig. 27.16). When viewed with transmitted light, a shape similar to the peak of the large stack is visible just to the right of the large stack, but it is unclear if this is related to an earlier form (fig. 27.17). Parts of the sky and the hillside, especially on the left side, were built up using undulating, zigzag strokes, which provide a distinct texture in those areas (fig. 27.18). These rhythmic brushstrokes were worked wet-in wet, with subsequent colors applied on top when the paint was dry, leaving the underlying texture undisturbed.

Overall, the painting has a rich, brushmarked surface, built up in an open network of strokes that leaves small areas of ground and earlier paint layers exposed (fig. 27.19, fig. 27.20). In some places, the underlying paint strokes are so heavily built up that the texture remains visible even when their color has been completely covered by subsequent paint (fig. 27.21). In other areas, strokes of low impasto lie adjacent to thinly painted passages (fig. 27.22) or were dragged directly over exposed ground where the canvas texture remains evident (fig. 27.23). It appears that the artist incorporated additional medium into some of his paints to achieve a more fluid consistency.17 This can be seen, for example, in the swirl of deep-green and brown paint in the distant foliage to the left of the large stack (fig. 27.24). Here, the unmixed colors swirl together and the brushmarks have largely settled out to a smoother surface. In this area, the artist contrasted the smooth, fluid paint application with more textural brushstrokes and thinly applied paint layers where the canvas texture shows through, creating a varied surface. The thin yellow strokes, which were lightly dragged over the surface, depositing mainly on the high points of the underlying paint texture, were among the final additions to the painting. In some passages, particularly those associated with the more fluid paint applications, tiny bubble holes were often observed (fig. 27.25).18 Some areas of impasto look slightly flattened. While this effect can be caused by the lining process, here it looks like it may have occurred early on when the paint was still soft (fig. 27.26, fig. 27.27). The upper left and lower right corners of the painting look like they were reinforced by the artist after the painting was finished.19 In the upper left corner, the pale-blue paint added at the edges appears more fluid (at the horizon, a drip is visible) and opaque, but it looks like it was applied wet-in-wet with the adjacent sky paint (fig. 27.28). Along the lower right edge and corner, there is a band of pinkish-purple paint that appears more solid when compared with the discrete strokes used in the adjacent field. Here, the added paint at the edge appears to have been applied when the underlying paint was dry (fig. 27.29).

Painting tools

Brushes including 1.0 and 1.5 cm width, flat ferrule (based on width and shape of brushstrokes). Smaller brushes or the narrow end of a brush were perhaps used for finer strokes. Several brush hairs are embedded in the paint surface.

Palette

Analysis indicates the presence of the following pigments: lead white, cadmium yellow, vermilion, red lake, emerald green, viridian, cobalt blue, and ultramarine blue.20 [glossary:UV fluorescence] of many of the red and pink paint strokes indicates the liberal use of red lake throughout the landscape.21 Paint layers were found to contain complex mixtures of pigments (fig. 27.30). 

Binding media

Oil (estimated).22

Surface Finish

Varnish layer/media

The painting was cleaned in 1996 and was left unvarnished (see Conservation History). The painting has a subtly variable surface (matte in some areas, low gloss in others) depending on the qualities of the paint.

Conservation History

The painting was already wax-resin lined when it entered the collection in 1985. The date of the lining is unknown. [glossary:Retouching] observed around the edges of the painting probably dates to this treatment campaign.

In 1996, the painting was cleaned and left unvarnished. The treatment notes indicate that there were two [glossary:varnish] layers present on the painting. The upper layer appeared to be a [glossary:synthetic varnish], probably applied when the painting was lined. The lower varnish layer appeared slightly yellowed and may have been a thin [glossary:natural-resin varnish].23

Condition Summary

The painting is in good condition. The canvas is wax-resin lined and stretched taut on an expansion bolt stretcher with no planar deformations. Along all of the edges, there is cracking, abrasion, and small losses in the paint and ground layers, as well as some small tears in the canvas fibers at the foldovers. All of these areas are stable. There is a series of fine vertical scratches near the left edge of the painting and similar randomly oriented scratches in the upper left part of the sky that were made when the paint was still soft. Some areas of impasto, such as that along the right side of the small stack, appear slightly flattened. This may have occurred early on when the paint was still soft. There is an overall network of fine age cracks that is mostly visible only under magnification. Some light [glossary:stretcher-bar cracks] are visible in the sky. Localized microcracking observed in some yellow-green paint mixtures may be related to the degradation of specific pigments. There is some flattening of paint and embedded wood fibers in the rebate area, related to framing when the paint was still soft. There are also some gold residues from the frame along the bottom edge. Discreet retouching is present around the edges of the painting (especially top, left, and right). Several brush hairs are embedded in the paint surface.
Kimberley Muir

Frame

Current frame (installed in 1995): The frame is not original to the painting. It is a reproduction of a Louis XIII convex frame with carved acanthus leaf on a recut bed and a guilloche front molding (Paul Mitchell Ltd., London, 1995). The frame is water gilded over red bole on gesso. The outer ogee, scotia, hollow, and cove sight are burnished. The frame is toned with thin washes of oil paint and glue [glossary:size]. The carved jelutong wood moldings are mitered with dovetail splines. The molding, from perimeter to interior, is fillet with rocked recutting; ogee topped with rocked recutting; ovolo with carved acanthus leaf on a recut bed; scotia; hollow; guilloche frieze bordered by rocked recutting; and fillet with cove sight (fig. 27.31).24

Previous frame (installed by 1975; removed in 1995): The work was previously housed in an American, mid-twentieth-century, Louis XV reproduction frame with foliate cartouches and swept cabled sides, leaf-tip sight molding, and an independent linen-covered liner (fig. 27.32, fig. 27.33).25
Kirk Vuillemot