CHAPTER 1: Jackson Pollock's Drip Paintings: Tracing the Introduction of Alkyds Through Non-invasive Analysis of Mid-1940s Paintings

From an art historical perspective, the term ‘dripping’ is generally associated with the visual idiom of the American Abstract Expressionist Jackson Pollock (1912–56), one of the most influential painters of the twentieth century. From a technical perspective, Pollock's materials and tools were used in relatively unconventional ways. The artist laid the canvas on the floor and divested the brush of its familiar function, using the brush and other tools to drip, pour and splatter paint onto a horizontal plane from above.

The exact development of the drip technique has been a matter of long and inconclusive debates, but signs appeared already in the mid-1940s. This was a seminal period of experimentation which marked Pollock's abandonment of the symbolic imagery of his earlier pictures and his adoption of more abstract means of expression. It was an innovative period also in term of materials, since he began to use the materials that had become available at the time: industrial household paints and metallic pigments.

The technical investigation of several poured paintings from 1949 to 1952 demonstrated the extensive use of alkyd-based paint.^1,2  Exploiting the advanced rheological properties and rapid drying time of alkyd resin, Pollock could experiment in innovative ways, using various tools to fling and guide fluid paint. Alkyd was a perfect medium to allow Pollock to develop his new kind of visual expression, marked by sinuous and liquid lines.

Consequently, the objective of this technical study is to correlate the change in Pollock's use of materials with the evolution of his visual vocabulary, i.e. Pollock's abandonment of a more figurative subject matter for a completely abstract one, achieved with the dripping technique. During this period, Pollock shifted from artists' oil paints to a greater reliance on commercial alkyd-based paints. Using a non-invasive analytical approach, the authors investigated eleven works from the Peggy Guggenheim Collection (PGC), Venice, ranging from 1942 to 1947. These were the crucial years that marked Pollock's experimentation, which would eventually lead to a fully mature drip technique.

As noted, the 1940s were a watershed decade for Pollock, since his practice underwent a considerable evolution with regard to both his technique and materials. During those years, he abandoned figurative and symbolic subject matter in favour of a non-representational network of gestural drips and splashes. Any figurative connotations observable in Pollock's earlier works disappear after 1947. The influence of Cubism—Pablo Picasso in particular—had endured in Pollock's earlier work, but his interest in Navajo sand paintings and the experimental processes used by the Surrealists was an important force in his exploration of new techniques and subject matter. Pollock's transition was gradual, even halting: he progressed from figuration to images concealed under paint densely applied with fingers, palette knife or paint tubes, to more abstract paintings made solely by pouring and splattering paint on the canvas. The unprecedented spontaneity and liberty of gestures in his ‘drip’ works altered and expanded the definition of painting. Pollock worked from all sides of the canvas, which was placed horizontally on the floor. He felt that this positioning enabled him to control the application of paint and be most connected to the act of painting.

Such an innovative artistic process was at least partially based on the flow of imagination and plain creative impulse, or creative accident, as Pollock tested various methods of paint application that challenged convention. In considering the spontaneous element of chance in Pollock's compositions, one should reflect on his interest in the Jungian notion of the collective unconscious and the Surrealist concept of automatism, when unpremeditated actions are used to express the force of the unconscious. Such an experimental process was an important force in Pollock's search for a new, American¹ subject matter and for the technical means to give it visual expression. However, it is also important to note that Pollock would return to his paintings after some time in order to finish them, thus moving back and forth between them. This allowed him to exert control and develop his compositions, working on several paintings simultaneously. In fact, Pollock denied the spontaneous and impulsive character of his gestures. In a handwritten statement, he emphasized that ‘new needs demand new techniques—total control—denial of the accident —states of order—organic intensity—energy and motion made visible’.⁵  Yet, in an interview with Selden Rodman in the spring of 1956, shortly before his tragic death, when asked whether he had “any preconceived visual image in mind, or [whether it was] the result of a wholly spontaneous, something that happens in the process of paintings”, Pollock replied hesitantly: “How do I know? I have and I haven't.” Nevertheless, he then pointed out: “Something in me knows where I'm going,” thus ultimately and undeniably asserting the intentionality of his working process⁶ .²

Each painting created by Pollock was idiosyncratic and varied considerably in terms of paint application, thus proving his mastery. In his statement, Pollock implicitly admitted that he had a specific vision for each painting. Indeed, he declared that his paintings were not disordered, essentially affirming that he looked at the liberated dripping technique and the lines he laid on the canvas, even if in constant tension and dialogue with his unconscious urge to paint freely, as controlled and not accidental. Additionally, although his poured works appear on the verge of complete abstraction, Pollock suggested that “he wasn't just throwing paint, he was delineating some object, some real thing, from a distance above the canvas”.⁸  He believed that he was drawing not on canvas, but in the air. Lee Krasner described Pollock as “working in the air”, creating “aerial form[s] which then landed”.⁸  As Naifeh and White Smith concluded, Pollock “was a figurative painter in hiding. In fact, he never stopped being a figurative painter, according to [Krasner], but his figures were ephemeralcreations, ‘airy nothings’ that existed only momentarily in mid-air loops of paint, then disappeared, leaving behind their vacated ‘skins’ on the canvas”.⁸ 

The evolution of Pollock's techniques and the crescendo of his ever more abstract imagery are perfectly reflected in the eleven works in the holdings of the Peggy Guggenheim Collection (Solomon R. Guggenheim Foundation), which date from 1942 to 1947. These works encompass Pollock's earlier abstract-figurative paintings, often marked by mythological subject matter, as in The Moon Woman (1942), painted with a traditional easel painting technique of oil paint applied with a brush. The composition, palette and execution all attest to Pollock's indebtedness at the time to Pablo Picasso's visual idiom, in particular to his painting Girl before a Mirror (1932; Museum of Modern Art, New York). Circumcision (1946) belongs to the transitional period of Pollock's evolving visual idiom. The artist then moved towards the abstract and heavily impastoed paintings of the Sounds in the Grass series, such as Croaking Movement (1946) and Eyes in the Heat (1946), both of which he executed by squeezing paint from tubes directly onto a canvas. The group of paintings Peggy Guggenheim decided to keep for herself³ reaches a culmination with Pollock's signature examples of his drip paintings, Alchemy (1947) and Enchanted Forest (1947), which he created with the canvas placed on the floor. Alchemy is a complex work painted with a variety of materials applied in various ways: squeezed directly from the tube, applied with a paintbrush or a spatula or dripped and splattered on the canvas.

Pollock was introduced to the use of liquid paint in 1936 at an experimental workshop in New York City taught by the Mexican muralist David Alfaro Siqueiros. In the early 1940s, Pollock started to pour colour directly from the can or with the help of unconventional tools. In October 1945, Pollock moved to Springs, East Hampton, at the east end of Long Island, New York, in a house currently known as the Pollock-Krasner House and Studio. There he began to paint on unstretched canvases laid on the studio floor, approaching the canvas from all sides, using sticks, old hardened brushes and knives to collect the paint from the jars and then drop it onto the canvas, developing what would be later called his drip technique. His mature dripping technique appears in paintings he created after 1948. Scientific data¹  suggest that he regularly used the relatively new, synthetic resin-based paint called alkyd enamel. Photographs of Pollock in his studio⁹  and interviews with his wife Krasner¹  indicate that he used paints produced by the DuPont Company, a leader in the manufacture of alkyd resins.¹⁰ 

Alkyd resins, also called glyptal,¹⁰  were synthesized at the beginning of the twentieth century by combining oil or oil-derived fatty acids into a polyester polymer structure. Chemically, an alkyd resin is an oil-modified polyester made by condensation polymerization of three components: di-carboxylic acid (phthalic anhydride), polyhydric alcohol and triglyceride lipids. Glycerol, trimethylolpropane and pentaerythritol are the polyalcohols commonly employed.

The development of alkyd resins completely revolutionized the paint and coating industry. Alkyd-based house paints are commonly found in works of art. During World War II (1939–45), these gloss enamel paints were more readily available than artists' oil paints and less expensive. However, the enhanced properties of these newly produced synthetic resins were also most attractive when compared to traditional artists' oil paints. The fast drying time (on the order of hours) was appreciated by artists accustomed to waiting weeks for the drying of traditional artists' oil paints. In addition, alkyds' glossy appearance appealed to artists wishing to juxtapose matte and glossy passages. Overall, the improved rheological properties of alkyd resins allowed Pollock to adopt unorthodox techniques such as dripping and pouring, enabling the creation of a range of unusual effects and textures that could not be achieved using traditional artists' oils.

Among the scientific methods available to heritage scientists, those based on mass spectrometry allow the most detailed information on the molecular composition of the synthetic binding media. As for alkyd resins, by combining Gas Chromatography–Mass Spectrometry (GC-MS), High-Performance Liquid Chromatography (HPLC)–MS and flow injection analysis (FIA)–MS it is possible to obtain from a minute sample of the paint the fatty acid profile and aromatic fraction of the resin, as well as identifying pentaerythritol, phthalic acid ester and the triglyceride residues of the synthesis process.¹¹ 

The past decade has witnessed significant changes in heritage science as paint sampling has increasingly given way to non-invasive, analytical techniques carried out with mobile instruments that can be brought to the paintings for in situ analysis.^12,13 

Among the non-invasive methods available today, Fourier Transform Infrared (FT-IR) reflection spectroscopy (in the mid 4000–400 cm⁻¹ and near 12 000–4000 cm⁻¹ infrared range) is most suitable for binding media analysis. The analysis of the spectral properties of paint reconstructions made of different types of synthetic (and natural) polymeric paints allowed Rosi et al.¹⁴  to demonstrate that, despite the spectral distortion occurring in reflection mode, the main differences among the vibrational profiles of different polymeric backbones are still appreciable and exploitable for their non-invasive identification. Figure 1.1 reports a comparison of the FT-IR spectral profiles of different binding media that are of interest for this study. In particular, the alkyd resin profile (grey line), recorded from a model painted with white barium sulphate in the wide infrared range (6000–400 cm⁻¹), is compared with the spectra recorded on the same white pigment painted with oil (black line), acrylic (blue line) and vinyl resin (magenta line). In the mid-IR range the marker vibrational mode of the alkyd resin is the C–O–C stretching,^14,15  appearing as a derivative-like feature at about 1270 cm⁻¹, being absent or very weak in polymers like oil and acrylic or upshifted with respect to the corresponding mode in vinyl resin. This band falls in a range relatively free from overlapping, which, combined with its strong/medium intensity, makes its visualization possible also in complex paint mixtures.¹⁴  The other portion of the spectral profile is rather similar to that of oil, including the carbonyl stretching (νC=O) at about 1740 cm⁻¹ and the CH stretching mode (νCH) at about 3000–2800 cm⁻¹. In the near-IR range, except for the combination (ν + δ) of the CH functional group which is very similar to that of the oil binder, alkyd resin can be distinguished from oil by observing a band at 4684 cm⁻¹, possibly due to the combination of the CH and C=O stretchings (νCH + νC=O),¹⁴  but also tentatively assigned to combination bands of the aromatic component of alkyds.¹⁶  This last feature is clearly present also in vinyl and acrylic resins and cannot be used for the alkyd identification (Figure 1.1).

Although the mid-IR range is more specific for the alkyd identification with respect to the near-IR window, the latter is presently also accessible through hyperspectral imaging instruments that allow the chemical identification and spatial localization at the macro-scale of the material composition.^16,17 

To the best of our knowledge, the results of micro-destructive MS analysis of binding media were published for fourteen paintings by Pollock (see Table 1.1).^1,2,18,19  Overall, the collection of MS data reveals that alkyd appeared first in 1947, then consistently in all the later paintings, as already reported by Lake et al.¹ 

The exploitation of non-invasive FT-IR reflection spectroscopy allowed for an extension of the information focusing on paintings realized in 1942 to 1947 belonging to the PGC (data are collected in Table 1.1).

In agreement with previous data,^1,18,20  our analysis clearly evidenced the use of alkyd resins by Pollock in 1947 as binder of the glossy and matte black paints (possibly made of vegetal carbon black) poured in Alchemy²⁰  and Enchanted Forest (Figure 1.2). The identification in both paintings was achieved by evaluating the mid-IR range because strong absorption by the black pigments in the near-IR range resulted in little-to-no reflected near-IR light being collected.

More surprisingly, we also observed the presence of alkyd in two out of the seven paintings dated 1946. In Eyes in the Heat (late 1946; a detail is shown in Figure 1.3a), the poured orange paint is composed of chrome orange (as indicated by Raman spectroscopy; Figure 1.3b), lead white and barium sulphate clearly bound with an alkyd binder (Figure 1.3c). In Untitled 1946 (a 1946 work on paper), some of the black and yellow poured paints were possibly made of an alkyd medium. In Figure 1.4 the spectra recorded in some of the glossy black and transparent yellow areas of the painting are reported.

Finally, leaving aside the works in the Peggy Guggenheim Collection and looking at those in the National Gallery of Art, Washington, Figure 1.5 depicts the macro-scale spatial distribution of the oil and oil-modified alkyd binders in the painting Number 1, 1950 (Lavender Mist), as obtained by hyperspectral near-IR reflectance imaging already published in ref. 16. In order to enhance the spectral differences of oil and alkyd, a first-derivative transformation was applied to the hyperspectral cube and the resulting processed images clearly unravel the complex paint texture and layering executed with the two oil-based binders.

The comparison of scientific analyses on binding media of twenty-seven paintings by Pollock, with related textural effects, offers interesting observations (Table 1.1).

Oil binders (both as artists' materials and/or house paint commercial products) have been mainly identified in the paintings of the first half of the 1940s, where the more traditional paint brush applications prevail over limited unconventional squeezed and/or dripped paint (Table 1.1). Pollock's earlier abstract-figurative paintings are still painted with a traditional brush and oil paint on a primed and stretched canvas placed on an easel, as observed in two works in the Peggy Guggenheim Collection: The Moon Woman and Two (1943–45). Although Pollock was still using relatively conventional painting methods, during this period he began introducing other, more intricate techniques, as observed in such works as Composition with Pouring II (1943). This work reveals a certain complexity, as Pollock used a variety of techniques ranging from brush, squeezed and splattered paints to poured and dripped applications. He mainly used artists' paints in tempera, oil and oleoresin media, and house paint in the glossy dripped black, one of the last paints applied, although not composed of oil-modified alkyd resins.¹ 

Surprisingly, the first documented occurrence of alkyd resin, so far dated to 1947, in the present study is now anticipated to be 1946.^1,18,20 

Indeed, it has been detected in the orange paints of Eyes in the Heat and possibly in the yellow and glossy black paints of the work on paper Untitled, both dated 1946.

Indeed, 1946 is a transitional period. Circumcision, defined by figurative references and a relatively organized pictorial field, reveals a looser application of paint, albeit highly controlled. The animated line applied with evident vigour becomes the protagonist of the scene. Nonetheless, in the same year Pollock painted the Sounds in the Grass series, such as Croaking Movement (1946), Eyes in the Heat (1946) and Shimmering Substance (1946)¹ . In these paintings he manipulated the pigments on the surface, spreading and pushing them with the help of utensils, and purposefully creating an emphatic, painterly texture. Eyes in the Heat, for instance, is covered with thick and vigorously worked paint, leaving no part untouched. However, Pollock still seemed to concentrate on the space as delimited by the edges of the canvas, rather than allowing the paint to potentially extend beyond the pictorial field. His ceaseless, active lines twist and turn towards the margins, yet do not surpass the edges. The dense, rhythmic web of white strokes seems to conceal the bodies of the creatures to which the ‘eyes’ of the title belong. Partially obliterated, thick, black lines—outlining what may be a ‘primitive’ figure—provide structure to the composition. The viewer's eye finds no repose, and this induces the sensations of intensity and heat inferred in the title. It is key to note that here Pollock used alkyd paints even prior to placing his canvases on the floor and developing his later drip compositions.

As a matter of fact, historical records report that the winter of 1946–47 marked a decisive turning point in Pollock's style: he began experimenting with painting by placing the canvas on the floor of his barn-studio in Springs. This watershed moment was accompanied by the permanent appearance of alkyd resins in Pollock's art.

Among the four investigated paintings, those dated to 1947 have all been executed with at least one alkyd-based paint. Carbon black alkyd media were found in Alchemy, Enchanted Forest and Reflection of the Big Dipper (carbon black-containing green paint) (Stedelijk Museum, Amsterdam, Netherlands),¹⁸  whereas in Full Fathom Five (Museum of Modern Art, New York), dark blue and dark orange alkyd paints are splattered with oil-based artist's binders and oleoresin commercial house paints.¹ 

Although the dripping experimentation started earlier (Table 1.1), paintings of 1947 present a radical departure from figurative work that relies on a Cubist grid and symbolic subject matter, in favour of a non-representational network of gestural drips and splashes. In other words, Pollock's so-called ‘drip period’ started and marked the beginning of his mature style.

Among the paintings of this period, one should not discount the possibility that Alchemy (1947) might have been Pollock's first highly experimental ‘drip’ work. The photographs taken by Herbert Matter in the summer of 1947 are the seminal documentary evidence remaining of Pollock at work on Alchemy in his studio in Springs. In one of them, Pollock crouches on the floor, and the canvas is attached to a quilting frame that belonged to his mother Stella, who was a skilled seamstress and weaver.⁴

In Alchemy, Pollock envisioned a precise compositional order created through his controlled drips of paint, and through an arrangement of counterpoints and symmetries, in which straight lines play against curved lines, brilliant colours against opaque colours, black with silver and blue with red.²⁴  From the outset, Pollock had a general framework in mind and proceeded with his guiding hand to direct the composition. Therefore, Alchemy seems to represent the various steps of the unfolding of Pollock's subconscious on the canvas surface through a predetermined working method, a process akin to jazz improvisations.

Alchemy itself is the prime example demonstrating the fact that Pollock did not apply all layers of paint at once. The material surface of the painting is dense and heavy, with fifteen different colours applied. Historical photographs depict Alchemy essentially finished in his studio, while four smaller dripped or poured paintings and at least one earlier work are stacked around the walls on the barn-studio. The paintings—Composition with Black Pouring, Galaxy, Phosphorescence and Reflection of the Big Dipper—are not all finished at the time the photographs were taken, suggesting that Pollock must have returned to complete some of his works after some time. Most likely, he put a layer of paint on the canvas, and while waiting for it to dry he proceeded to work on his other paintings.

It may also be assumed that the experimentation with Alchemy made him understand that a canvas with a thick, rich surface could crack when put on a stretcher, generating losses. The losses and the paint cracking that he may have witnessed in Alchemy might have given him the impetus to change his painting style in order to make it more fluid, resulting in a flatter surface. If this were true, then Enchanted Forest, characterized by a markedly flatter surface, would have been created after Alchemy. Enchanted Forest has characteristics of many of Pollock's mature compositions: a reduced range of colour, space for black and white to breathe and find their balance on the canvas. Line, laid on the canvas in a way that resembles script, embodies the only form the eye can trace: it neither implies space through perspective nor defines shape through contour. Its constant mobility allows no rest for the viewer's eye, even if the palette is subdued. Small patches of red and gold protrude, making the composition ever more vivid. There is no central focus here, and we are denied the safe ground offered by the traditional subordination of technique to subject matter. Here, colour and line are themselves the subjects.

In subsequent years, Pollock began to use even more diluted paint that flowed better and allowed him to have even more control over his works. In a handwritten statement in ca. 1950, he noted: “Most of the paint I use is liquid, flowing/the brushes are used more as sticks and do not touch the surface/I'm able to be more free and move about with greater ease/it seems to be possible to control the flow of paint to a great extent/I deny the accident…”.⁵ 

It is not possible to demonstrate that Pollock's satisfaction expressed by this statement could be connected to the availability of the new oil-modified alkyd resin offering him the possibility of technically expressing his art. However, based on scientific examinations (Table 1.1), after the first introduction of alkyds, the new resins appear frequently in the later paintings, clearly indicating their extensive use by Pollock.

According to ref. 1 and 2, destructive investigation of a number of samples revealed that: in painting Number 12 (1949) although not specifying the total number, all the samples are alkyds; in Number 10 (1949), six samples out of seven are alkyds; in One: Number 31 (1950) three samples out of three are alkyds; and in Yellow Island (1953) six samples out of seven are alkyds. This results in a percentage of oil-modified alkyd presence in the range of 85–100%. The extensive use of the oil-modified alkyd binder can be clearly appreciated from the material maps obtained by near-IR reflectance hyperspectral imaging of Number 1, 1950 (Lavender Mist) (Figure 1.5) where the texture of squeezed artists' oil paint is complemented by poured alkyd resin house paint.¹⁶ 

The present non-invasive study revealed that oil-modified alkyds were introduced in Pollock's materials in 1946, updating previous records referring to 1947. The identification of the synthetic resin was carried out by non-invasive FT-IR reflection spectroscopy on Pollock's works at the Peggy Guggenheim Collection in Venice, which holds eleven paintings from the period 1942–47. Combined with previous scientific examinations carried out on fourteen paintings through destructive methods on samples, the study enabled the evaluation of the occurrence of the oil-modified alkyd resin in the paintings dated 1942–52. The dripping paints appeared before the use of alkyds (in agreement with the previous study,¹  Pollock in fact started experimenting with both artists' and house paints). The introduction of the oil-modified alkyd offered Pollock the suitable binder for expansively expressing his action painting in the paintings after 1947.

From a methodological point of view, it should be emphasized that the overall considerations resulted from analysis of tiny samples that are not fully representative of the entire material composition of a painting. The results are improved by using non-invasive methods such as single-point FT-IR reflection spectroscopy, enabling the non-invasive collection of a theoretically infinite number of points. As a matter of fact, when investigating complex paintings such as those by Pollock, a non-invasive single-point technique also presents a limited representation. Presently, the use of hyperspectral reflectance imaging methods can overcome this limitation by maintaining the spectral specificity of single-point techniques while offering the macro-scale chemical localization of the binders, thus enabling both a better representation of the composition overall and visualization of complex layering and textures as demonstrated for Number 1, 1950 (Lavender Mist).