A Vibrant Surface: Investigating Winslow Homer's Watercolors

CHAPTER 19

A Vibrant Surface: InvestigatingColor, Texture and Transparency inWinslow Homer’s WatercolorsB. BERRIE,a F. CASADIO,*b K. DAHM,b Y. STRUMFELS,c M. TEDESCHIb

AND J. WALSHd

a National Gallery of Art, Washington DC, USA; b Art Institute of Chicago,Chicago, IL, USA; c U. S. National Archives and Records Administration,Washington DC, USA; d State University of New York College at Buffalo,Buffalo, NY, USA*Email: [email protected]

19.1 INTRODUCTION

Identifying the pigments used by painters complements stylistic an-alysis with information on the evolving use of the materials andmethods of art-making. Our knowledge of the changes pigmentsundergo helps us evaluate individual works based on the colors andcolorants found, predict the artwork’s preservation needs, and placeindividual works within the artist’s body of work. Material analysisusing non-sampling methods when possible is key to obtaining thisinformation as the opportunity to take even miniscule samples fromwatercolor paintings is limited.

Here, we present the combined results of two investigations of thecolorants in watercolor paintings by the American master WinslowHomer (1836–1910).1,2 Although as early as 1859 Homer had

Science and Art: The Painted SurfaceEdited by Antonio Sgamellotti, Brunetto Giovanni Brunetti and Costanza Milianir The Royal Society of Chemistry 2014Published by the Royal Society of Chemistry, www.rsc.org

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employed watercolor to tint his designs for wood engravings, hisserious ambitions for watercolor paintings began rather abruptly inJuly 1873 and continued to 1905, eventually producing 735 knownworks.3 The corpus examined for this study gathers for the first timeresults from a group of artwork that is large enough to representadequately Homer’s entire career. Twenty-eight watercolors wereanalyzed at the Art Institute of Chicago (twenty-three from the AICcollections, three owned by The Terra Foundation for American Artand two in private collections) and thirty-one from the collections ofthe National Gallery of Art, Washington, D. C. (NGA) were studiedthere.4 The 59 works represent well Homer’s watercolor palette for themore than three decades in which Homer worked in watercolor andrepresent all geographic venues in which he painted in the medium.The results discussed in this study are enhanced and contextualizedby comparison with the pigments identified in two watercolor boxesused by Homer.1,5,6 One is preserved at the Portland Museum of Art,Maine, and the other at Bowdoin College, Brunswick, Maine. Theextant boxes confirm that Homer favored art materials from Winsor &Newton, the venerable British firm.7 Two sable ‘‘mop’’ brushes, anda canvas-carrying pouch belonging to the artist were also sold byWinsor & Newton.8 Since the firm offered over 125 colors of watercolorpaint during Homer’s career, his choice was essentially unlimited.

Winslow Homer pursued a scientific approach in his use of colors.Very early in his painting career, in 1860, Homer’s brother Charlespresented him with a copy of a recent translation9 of the Frenchchemist Michele-Eugene Chevreul’s (1786–1889) masterwork Chevreulon Color, first published in Paris in 1839. Homer became intimatelyfamiliar with Chevreul’s theories over long study—his marginalia aredated 1860, 1873, 1882 and 1884.w In 1903, he described the book as‘‘my bible’’. Homer’s protracted study of this work gained him a so-phisticated understanding of the most recent science of his era; hisstudy of color was doubtlessly motivated by his desire to impart visualhonesty to his work.2

The scientific study of physiological optics as first reported byChevreul was carried forward by the American physicist Ogden Rood(1831–1902) in his masterwork on color theory and color mixing,Modern Chromatics (1879). Rood was undoubtedly known to Homerpersonally, and it is likely that the two discussed color theory as Roodconducted his experiments and prepared his popular lectures forartists. Both scientists described how an artist might manipulate the

wHomer’s copy of Chevreul is now in the collections of the Strong Museum in Rochester, NY.

405A Vibrant Surface: Investigating Winslow Homer’s Watercolors

viewer’s experience by exploiting the variability of sight, thus ex-panding the perceived range of each colorant. The emphasis on thereader’s own experience of color made their work accessible to artistswho might apply the theory to clarify and intensify their painted color,and harmonize the colors required in any composition. By changingtheir juxtaposition to other colors, Chevreul and Rood taught, pig-ments would be perceived as more clear and brilliant or subdued andgrey. Chevreul called this phenomenon the ‘‘Contrast of Colors’’, theoptical illusion that colors create in each other when placed in closecontact. Complementary colors—red and green, blue and orange,yellow and purple—tend to clarify and heighten each other, whilecolors that are not complements tend to diminish and subdue oneanother. An artist needs to understand both phenomena, since bothbrilliant and subdued colors are needed in compositions.

Homer was among the first in his generation of artists who actuallystudied modern color theory carefully to properly apply the scientificrevelations in his work. He was a thoughtful and thorough student ofthe science. ‘‘You can’t get along without a knowledge of the prin-ciples and rules governing the effects of one color upon another.A mechanic might as well try to get along without tools,’’ he said.10

Many clear examples of proper application of color theory can befound in all periods of his watercolor work.2

Homer seems to have deliberately ignored some inconvenient sci-ence, however. As early as 1887, Winsor & Newton included infor-mation about the permanence of their pigments in ‘‘shilling books’’called Descriptive Handbooks of Modern Watercolor Pigments. In 1888,in response to the ‘‘Watercolor Controversy’’, The Russell-Abney Re-port, commissioned by Parliament, confirmed the information firstgathered by A. H. Church in 1856, on the relative permanence of in-dividual watercolor paints. The results of these studies were widelypublished and debated in arts organizations and the press. With ourstudy, we show that Homer did not change his palette in response tothis science; he persistently continued to use some colors despite in-vestigations that showed them to be impermanent.

19.2 ANALYSIS STRATEGY AND METHODOLOGY

Analysis of pigments in watercolor paintings is challenging sinceusually there is a very small quantity of material present in the thinpaint films, and the surface is very delicate: for these reasons non-sampling analytical methods are preferred. However, the paper sub-strate, usually coated with sizing agents such as alum, rosin or

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gelatin, gives a background signal which for many types of in situanalysis reduces sensitivity and interferes with interpretation of theresults. We have, therefore, in a few instances, obtained small sam-ples, especially where organic colorants were suspected. All thewatercolors were extensively examined using optical stereomicroscopy(OM) and X-ray fluorescence spectroscopy (XRF). Optical stereo-microscopy is a valuable tool to determine color, shape, relief andother useful particle characteristics, while also providing clues to theuse of layered and mixed colors. Finding particular elements usingXRF often suggests specific pigments for a given color; however, whenmore than one pigment can account for the presence of an element orcombination of elements, complementary analyses are needed toconclusively identify materials. Air-path XRF instruments also displaylow sensitivity for the detection of light elements such as silicon,aluminium, magnesium and sodium (Si, Al, Mg, Na), which arecharacteristic of some clay minerals (present in earth pigments suchas ochers and green earths), as well as the blue pigment ultramarine(Na8–10Al6Si6O24S2–4). Therefore, in some instances, vibrational spec-troscopies (Fourier-Transform infrared and Raman spectroscopies)were used to identify such blue and green pigments. Blue pigmentswere also distinguished by their varied reflectivity/absorbance whensubject to infrared imaging.11,12 In some cases, Raman spectroscopywas used to identify indigo (C16H10N2O2) and other organic colorants,such as Indian yellow (magnesium euxanthate, C19H16O10), which wasalso identified using Fourier-Transform infrared spectroscopy (FTIR).Gamboge yellow (gambogic acid, an exudate from the Garcinia spe-cies of trees, C38H44O8) was identified by its distinct visual charac-teristics using a stereomicroscope, in one case confirmed with FTIR(Figure 19.1).

Ultraviolet illumination and documentation occasionally allowedthe determination of the extent of usage of some pigments. For ex-ample, when the strong yellow emission of zinc white (ZnO) was de-tected alongside the XRF determination of the element Zn at specificlocations, the presence of the pigment could then be inferred also inother areas in addition to the ones probed with XRF, based on theautofluorescence. UV illumination also revealed the distribution ofsome organic dyes, even when they had undergone significant fading(Figure 19.2).

The identification of red, pink and purple lake pigments in water-colors is challenging and was tackled on a case by case basis withanalytical protocols of increasing complexity. Generally, lakes werecharacterized using microscopic observation and XRF detection of the


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inorganic substrates containing calcium, aluminium or tin. In thiscase, a generic identification of red lake is used in Table 19.1. At theNGA, visible reflectance spectroscopy was used to class pigmentsmade using organic red colorants as insect- or plant-derived, or syn-thetic. However, further characterization using this technique is dif-ficult.13,14 For example, cochineal (carminic acid), the colorant inmany organic red paints, can have a variety of hues depending on theinorganic substrate (or mordant) chosen for the preparation of thelakes, and pH. Therefore it is risky to use the visual appearance oreven visible reflectance spectroscopy for precise identification,

Figure 19.2 Detail of North Woods Club, Adirondacks (1892) photographed usingultraviolet light (top) shows pink fluorescence of faded red lake pig-ments, no longer visible in the image under white light.


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particularly when there are mixtures of pigments, though this hasbeen applied with a degree of success in some cases.14 In favorableinstances, fluorescence emission can be used to identify red lakes, butfor these watercolors the background emission is strong and variable,so determination of the signal from the colorant is extremely chal-lenging.15–17 In just a few cases, minute samples of red pigments wereobtained from watercolors at the AIC for analysis using FTIR, whichyielded good results due to the minimal amount of binder and fillersthat can interfere with signals from the chromophore (Figure 19.3). Inisolated instances, the technique of surface enhanced Raman spec-troscopy18,19 was used for the positive identification of red colorants

Figure 19.3 FTIR spectra of: (a) bright fuchsia particle (shown in the micrographat right) removed from an area above the branches of North WoodsClub, Adirondacks (1892), pictured in Figure 19.2. The paper fibers hadprotected some of the pigment from fading. Although the spectrum isdominated by the features of the substrate for the lake, hydratedalumina, some of the bands characteristic of anthraquinones arevisible. The spectrum matches well with a reference sample of pinkmadder watercolor from a Winsor & Newton 1887 book shown in (b).(c) Red lake particle (shown in micrograph at right) removed frompurple brushstrokes in the water at the edge of the lower right cornerof The Water Fan, 1898/99. Although the spectrum shows the bands forgypsum (G), present either as an extender, or more likely the substratefor the lake, and Prussian blue (P) used to depict the water, thecharacteristic bands for cochineal are also visible, and match wellwith the reference spectrum (AIC Forbes collection R182 CochinealWeber), shown in (d).

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(Figure 19.4). In cases when alizarin or carminic acid were identified,then the terms madder and carmine, respectively, are used in thetable.

19.3 RESULTS

19.3.1 Overview

The analytical results for the 59 watercolor paintings are aggregatedinto Table 19.1. The table does not indicate the amount of a particularcolorant nor the mode of use (pure, layered, and mixed, etc.), yet itoffers some interesting immediate results and considerations onchronological pigment use.

The number of pigments Homer used in a painting ranges from six(1874 and 1903) to fifteen (1892) and averages eleven. The numbersdo not correlate to particular time periods, although all works con-taining more than eleven pigments were completed during or afterHomer’s time in England from 1881 to 1882. Certain pigments—indigo, Prussian blue (KFe[Fe(CN)6] � 12–16H2O), chrome yellow(PbCrO4), red lake, iron earth (Fe2O3), and vermilion (HgS)—remained on his palette throughout his career, while others wereintroduced then dropped. Zinc white occurred in all the earliestwatercolors examined, but over time was more rarely used. Likewise,

Figure 19.4 SERS spectra of (a) a reference sample of Indian purple watercolorfrom a Winsor & Newton watercolor book with painted examples;20 (b)a burgundy-red colored pigment grain removed from the sky of For tobe a Farmer’s Boy, 1887 and (c) a reference spectrum of powderedcochineal lake pigment. (The asterisk indicates bands for citrate, areagent used in the preparation of silver colloids.)


chrome green, a mixture of Prussian blue and chrome yellow, whileused very often in the early years, was not found in any works datedafter 1892, giving way to a wide range of mixed greens. These mixtureswere not commercially available and we speculate they were preparedby the artist himself. In 1881, Homer suddenly augmented the rangeof yellows on his palette, while simultaneously dropping the use ofaureolin (K3[Co(NO2)6] � 3H2O), which reappeared on his palette againonly a decade later. Despite the variety of blue tones in Homer’s 1881English watercolors, Prussian blue, Antwerp blue, and indigo, withtouches of ultramarine (Figure 19.5) were the only blue pigments heused in these paintings of sea and sky, attesting to his facility with

Figure 19.5 Raman spectra of (a) blue pigment particles removed from the sky inthe upper right corner of The Watcher, 1882 (details shown at left)showing indigo and Prussian blue (lexc¼ 532 nm; all peaks notmarked P for Prussian blue are related to indigo); (b) blue and greenparticles removed from brushstrokes in the water in the lower leftcorner of Tynemouth, Priory, England, 1881 (details shown at right).Combined XRF, Raman and FTIR analysis showed Prussian blue,green earth and ultramarine blue in the brushstrokes used to depictthe water. The Raman spectrum shown corresponds to ultramarineblue (lexc¼ 633 nm); (c) green particles removed from a brushstrokein the water of the upper left quadrant of After the Hurricane, Bahamas,1899 (details shown below, as well as a photomicrograph of the pig-ment particles); the pigment was identified as emerald green(lexc¼ 532 nm).

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varying the effects of layering washes. Following his 1882 return toMaine from England, additional blues were introduced or appearedwith greater frequency: among these cobalt blue (CoAl2O4) andcerulean blue (Co2SnO4). Some newly added blues are noted for theirdifficult working properties. Cerulean blue is ‘‘apt to be chalky’’ and‘‘has no very striking artistic properties’’, likewise, ultramarine‘‘washes very badly’’.20 Yet Homer found both useful for renderingsubtle color contrast, although Prussian and indigo, which both washwell, predominated. Taking into account the analytical challengesposed by red lakes, as described in the previous section, this in-vestigation confirms Homers’ extensive use of red lakes, some ofwhich have been positively identified as madder and carmine lakes.Homer’s notation ‘‘C Lake’’ for crimson lake appears in the Bowdoinbox.8

In the following sections, we describe in more detail the importantobservations that can be derived from consulting Table 19.1, shed-ding light on the artist’s technique and clearly illustrating howHomer’s choice of materials was tailored to serve his evolving ex-pressive ambitions.

19.3.2 Shift from Opaque to Transparent Watercolor Technique

At the beginning of his watercolor practice, from 1873 to 1875,opaque paint and gouache painting techniques predominated inHomer’s watercolors. The opacity of watercolor paint depends onthe refractive index of the pigment, its particle size, and its concen-tration. Choosing colorants with different properties allows artiststo vary the translucency of their paint. Homer chose inherentlyopaque pigments such as chrome green, chrome yellow, and ver-milion. He also used zinc white extensively, mixing and layering itwith transparent watercolors to add body, opacity, and brightness. Hemay have used prepared body-colors with zinc white already mixedinto them. He exploited the properties of these paints to cover andbuild forms on colored paper, in a manner analogous to his oilpainting technique; he also exploited the ability to paint thickly, andapplied individual brushstrokes with control. Fresh Eggs and SickChicken, both dated to 1874, are typical of Homer’s early opaquewatercolors. The whole sheet is covered by opaque paints and zincwhite is used for highlights and mixed into most of the colorsgiving thick, stiff paints which he could apply precisely, as in thepolka dot pattern on the woman’s dress and straws in the haystack inFresh Eggs.


Homer first shifted to painting in a transparent manner on Englishwatercolor paper in a number of studio portraits executed from 1876to 1877 (years not represented in this study). One example of such astudio portrait is Woman and an Elephant, c. 1877, in the collection ofthe Albright-Knox Gallery of Art, Buffalo, NY. The following summerof 1878 was a time of transition and experimentation as Homerpainted similar subjects in both opaque and transparent methods.Many of the opaque pigments used in 1874 remained on his palette,yet the eight pastoral watercolors from 1878 show Homer’s increasinguse of transparent paint washes to render sketchy and en plein airstyle paintings. Rather than mixing zinc white into colors, in theseworks Homer applied scumbles of white paint over washes of color toportray landscapes bathed in bright light. Other paintings from thisperiod exemplify his transparent style. Homer altered his usual pig-ment choices to exploit the transparent qualities of the watercolormedium to paint Weary (1878). He all but eliminated zinc white, re-serving it only for highlights. He added Hooker’s and Prussian greens(Prussian blue mixed with transparent gamboge yellow varying byproportion), which were applied in broad, dilute washes on whitepaper in place of chrome green. Instead of chrome yellow, Homer useda transparent organic brown (such as Van Dyke brown) to warm thegrass in sunlight. Homer also began to experiment with manipulatingthe physical properties of different pigments for expressive effects. In1878, when he was painting Weary, he capitalized on the fact that theresinous component gamboge in Hooker’s and Prussian greens re-tained moisture and dried slowly, which enabled him to make use ofsubtractive techniques: thus he blotted and scraped wet green water-color to create highlights along the painting’s right side. In 1881–1882,Homer travelled to England and settled in the fishing village of Cul-lercoats, near Tynemouth. Here, he focused on increasing his facilitywith British watercolor techniques, namely building up transparentwashes in layers to achieve deep tones of color and recovering lightsusing subtractive techniques including rewetting, blotting and scrap-ing. Homer never returned to a completely opaque painting method.

19.3.3 Recurrent and Ubiquitous Pigments

Our study reveals that there are five pigments which are present inalmost every painting examined: vermilion, red lake, iron earth,Prussian blue and indigo. All five pigments are present in Homer’sextant watercolor boxes, documenting the persistence of thesematerials on the artist’s palette until the end of his life. These reds

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and blues anchor the chromatic warm and cool balance in Homer’sworks.

19.3.3.1 Vermilion and Iron Earth. Vermilion ranges in color frompale scarlet or orange to deep crimson red depending on its prepar-ation. Inherently opaque, it was ideal for the early opaque methodwhen applied in discrete, dense strokes. After his transition totransparent painting, Homer continued to find vermilion invaluablein diluted paint to obtain translucent washes; he persisted in rely-ing on the device of applying small strokes of pure, bright red tofocus attention within the work. In The Return, Tynemouth (1881),the artist applied final touches of pure vermilion around the fisher-men’s heads, outlined a hat brim, accented jacket collars, and col-ored the end of each buoy in order to direct the viewer’s attentionand unify the composition. In Salt Kettle, Bermuda (1899), Homerdabbed pure red directly over contrasting bright green to indicateflowers at the water’s edge. His deliberate choice of an opaque redpigment applied over green implements his interpretation of Chev-reul’s law of simultaneous contrast to achieve optical vibrancy.The artist also masterfully exploited the physical properties of thepigment particles to affect naturalistic renditions of his subjects.When applied in a dilute wash, the dense pigment particles settleinto the textured paper leaving a gritty surface that Homer ex-ploited to describe dirt and sand. In Garden in Nassau (1885), hebrushed dilute vermilion over the white paper to describe thelight-drenched dirt path. He used the same approach with a dar-ker vermilion wash to portray the Maine soil in For To Be a Farm-er’s Boy (1887). Homer made similar use of iron earth takingadvantage of its weight and density to render a grainy textureevoking sand in The Cock Fight (1885). He frequently used it formixtures to describe things as varied as the skin tones of localCaribbean people, rocks along the Maine shore, and the Adir-ondack forest floor.

19.3.3.2 Red Lakes. Red lakes produce transparent yet vivid reds,pinks and purples unmatched by other pigments. In 1882, Winsor &Newton offered nine hues of madder (three were synthetic alizarin)ranging from the palest pink ‘‘scarlet madder’’ to a deep, saturatedpink, ‘‘Ruby Madder’’ (alizarin). Their performance alone, layered,or in mixtures, made them versatile and useful. No other pigmentsimultaneously provided such clarity and depth of hue. Various redlakes describe the color of the sky at specific times of day, brightreflections on water, and the sun’s heat emanating from a forest or


shoreline. In 1880, Homer added washes of madder lake to warmthe sky, rocks and shore in Two Boys Watching Schooners. He pain-ted The Rise (1900) with carmine to infuse the dawn sky and its re-flections on the lake with the red light of sunrise.

Throughout his entire oeuvre, Homer used pigments that fade onexposure to light. The disappearance of red in his works has beendescribed and simulations made to approximate the original ap-pearance of some paintings.2,19 Some of the artist’s compositions arenow out of balance due to fading of these light-sensitive reds.Microscopic examination of Santiago de Cuba (1885) revealed both thesky and the foreground were once suffused with the deep pink hue ofa red lake. Only traces of a red wash remain today undermining theaesthetic impact of this composition. Many other works investigatedfor this study displayed similar, pervasive fading; some examples ofwhich have been described elsewhere.1,2,19

19.3.3.3 Prussian Blue and Indigo. Prussian blue and indigo havesimilar working properties that allowed Homer to merge and blendthem together. Both colorants are composed of finely divided par-ticles that allow paints to flow and mix well thereby providing awide range of related tones. Through most of his career, Homerused these blues in broad areas of sky and water (Figure 19.5). Theybecame a base for scumbling lighter, warmer hues or adding analo-gous strokes of other blue pigments.

Homer used to great advantage the close relationship between theinky, deep appearance of Prussian blue and the soft greyness of in-digo in A Good Shot, Adirondacks (1892). The work is an emotionallyengaging picture in which a serene, blue-green background provides acontrast to the image of a struggling wounded deer. Homer relied onbroad, fluid washes of two blue colors for the forest backdrop, mer-ging Prussian blue and indigo over the sheet and layering scumbles ofdilute cadmium yellow and chrome orange to generate a variety ofblue-green colors. In Chevreul’s terminology, these hues could beclassed as neighboring tones on the same scale. The artist’s shrewduse of adjacent touches of these pigments is an example of his abilityto depict form through the judicious use of strokes of slightly dif-ferent colors, precisely placed.1 For example, strokes on the deer’sfront left hoof appear to be of the same color, but analysis revealedthat Homer used Prussian blue and indigo, close in color and tone, tocreate the sense of the hoof clawing forward on the rock. Indigo hasgood lightfastness, but there is evidence from covered edges that ithas bleached in some watercolors.

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19.3.4 Pigments Restricted to a Location or Short Time Period

19.3.4.1 Copper-based Greens. Copper-containing greens have alimited role in Homer’s oeuvre, apparently restricted to a Bahamiantrip during winter 1898–1899, and a trip made to Bermuda in thefollowing winter of 1899. Raman spectroscopy of a single particlefrom a green stroke of paint on After the Hurricane (1899) (Figure 19.5),showed that in this watercolor, Homer employed pure emerald green(Cu4(CH3CO2)2(AsO2)2). A vivid, brilliant color, Homer used it to paintbeach grass and juxtaposed it with red to record vibrant reflections ona choppy sea. One year later, while in Bermuda, he picked up a brightgreen hue, using it for the shutters and their reflections on the waterand other touches of color in Salt Kettle, Bermuda (1899). In thispainting, however, the colorant is not emerald green since XRFshows that the pigment contains no arsenic (Figure 19.6). This col-orant has not yet been further characterized as a sample was notavailable at the time of analysis, but it seems possible that it is ver-digris. It is known that Winsor & Newton sold verdigris watercolors,and one of their competitors listed it in their trade manual of 1889.21

Neither emerald green nor verdigris was found in the two watercolorboxes analyzed.

19.3.4.2 Cadmium Yellow. The earliest positive identification ofcadmium yellow (CdS) for this study is in The Lone Fisherman(1889). Variations in particle size and chemical composition of thecadmium pigments yielded a range of bright hues from light yellowto orange.22 Homer’s choice was a bright, full-bodied yellow thatwhen applied in dry, opaque touches was well-suited for repre-senting yellow leaves or flowers in a forest or along a lake shore asin A Good Shot, Adirondacks (1892). He also used the inherently opa-que pigment in dilute washes. He kept it in his palette through thenext decade; it is found frequently in his Adirondack works, in oneMaine work and two tropical works. However, it was no longer de-tected in works after 1899 examined for this study.

19.3.4.3 Aureolin. Introduced in 1860,20,23 aureolin yellow is wellsuited to watercolor painting. Its intense yet semi-transparent colormakes it useful for mixing and layering, both of which Homer per-formed with increasing sophistication and complexity over time.Homer worked with aureolin often in his earliest opaque works ofthe 1870s, applying it for example as a glaze to create the color ofsunshine on a grassy bank in The Green Hill (1878). He all but drop-ped the pigment following the England years of 1880–1881,


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replacing it on his palette with gamboge, a yellow resinous colorant.After a decade in which the pigment disappeared from his works,from 1890 on, Homer reintroduced aureolin, rediscovering the col-orant’s pleasing hue and versatile handling properties. He used italone and in mixtures for many applications such as to describelight emanating from the dense Adirondack forest, pale green high-lights on tropical water, and vegetation on the Maine coast. A cakeof the pigment was present in the Portland watercolor box, whichhad been labeled in Homer’s hand, ‘‘Aureolin’’.

19.3.5 Rarely Found Pigments

There are six pigments that we identified only in three watercolors orfewer, four of which were identified in only one work. Green earth(K(Mg,Fe21)(Fe31,Al)[Si4O10](OH)2) was found only in Tynemouth Pri-ory, England (1881) in a blue-green brushstroke in the water, where itwas employed in touches over broader passages of blue and reservedwhite of the paper to describe the water’s undulating surface.The FTIR spectrum showed that the mineral celadonite is present(Figure 19.1). A sample of Winsor & Newton’s dry pigment terre vertedating to the 1920s was also celadonite.24

In the spare composition, Prout’s Neck, Evening (c. 1894), Homercombined Indian yellow with Prussian blue to paint the shadowy formof a juniper bush (Figure 19.1). Although we cannot exclude itspresence together with other inorganic yellows in other watercolors,because the main method of investigation for this study was XRF,Indian yellow was positively identified only once despite being pre-sent in the box at Bowdoin, where it was identified using X-ray powderdiffraction.5 This occurrence is notable as Indian yellow has rarelybeen identified in Western works of art.25 In Sunshine and Shadow,Prout’s Neck (1894), Homer mixed barium yellow (BaCrO4) withPrussian blue to obtain a brighter yellow-green used to capture theappearance of light transmitted through a distant wave.

Only two occurrences of umber were found: an early Maine paint-ing, Incoming Tide (1883), where umber appears in the brown rocksand in the purplish area in the water, and in a much later work,where we found umber used to portray the vest on one of the figuresin The Outlook, Maine Coast (1894).

19.3.6 Use of Mixed Colors vs. Prepared Colors

Throughout his career, Homer took advantage of commercially pre-pared colors. Cakes of mixed greens, prepared purples and notations


for Payne’s grey were found in Homer’s watercolor boxes. But he alsoindependently combined pigments to make specific colors. In someinstances, it is possible to distinguish between the artist’s mixturesand commercial preparations on the watercolor paintings by exam-ining the proportions and identities of the materials in the paints.Varying proportions of the constituting colorants likely indicate anartist’s and not a mass-produced color. Finding unusual combin-ations of pigments that are not listed in trade catalogs also points toan artist’s mixture.

19.3.6.1 Greens. Homer’s extant watercolor boxes contain eightgreen cakes, seven are types of Hooker’s or Prussian Green and onegreen earth. There are five pans of green in the Portland watercolorbox and three in the Bowdoin box. Two in the Portland box may bedesignated Hooker’s greens, since they contain a larger percentageof gamboge than the others, giving them a grassy hue while theother three cakes may be termed Prussian greens, because they con-tain a smaller proportion of gamboge resulting in a deep blue-greenpaint.26–28 A notation in Homer’s hand, ‘‘P Green’’ (for Prussiangreen) is visible on the Bowdoin box. On the Portland box, Homerwrote ‘‘P gr’’ (for Prussian green or Payne’s grey) and ‘‘Hook green’’for Hooker’s green.1 Fading of yellows has not been investigated asmuch as reds, but in many sylvan works, there has been a shift toblue due to fading of gamboge in the mixture. Gamboge used as aglaze has faded over time in many of the watercolor paintings.Furthermore, gamboge is solvent-soluble so conservation treatmentsinvolving solvents, such as tape removal, can result in a shifttowards blue as the gamboge is inadvertently affected.

One other mixed manufactured green, chrome green (a mixture ofPrussian blue and chrome yellow), was detected in the artworksexamined for this study. The evidence collected thus far suggests thatuntil 1892, Homer only used commercially prepared greens (bothmixture of pigments and as single colorants). Despite the varietyavailable, he began customizing his greens in his Adirondack worksof 1892 by mixing and layering various combinations of five yellows(aureolin, barium, cadmium, chrome and gamboge) and four blues(cerulean, cobalt, indigo and Prussian). Each of these pigments dif-fers in hue, transparency, gloss, and weight. Homer harnessed hisdeep grasp of pigment properties to prepare each green paint in orderto best represent the landscape. In North Woods Club, Adirondacks(1892), he used three mixed greens to paint the pine trees includingtwo mixed from Prussian blue, indigo and gamboge in varying

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proportions and one prepared from aureolin, barium yellow and in-digo. He painted other foliage by layering a chrome yellow wash overtwo greens he had made by blending aureolin with cerulean and co-balt blues.

19.3.6.2 Purples. Homer employed both purples that he mixedhimself and commercially prepared purple pigments. Of six Winsor& Newton purple watercolors described by Taylor, three were pre-pared using cochineal.20 Indian purple was described as a prepar-ation of cochineal ‘‘on a base of copper oxide’’ and Purple lake wasa ‘‘species of crimson lake’’.20 More specifically, Purple lake was amixture of carminic acid and calcium oxide.29 In 1898, it was statedthat ‘‘Indian purple’’ was imitated by combining madder lake andFrench ultramarine and was described as a ‘‘permanent substitute’’for the original formulation.30 Although Homer wrote Indian purplein the palette wing and a cake of paint is set in a pan that reads‘‘Indian purple’’, analysis did not indicate the presence of copper,as claimed in the formulation of Indian purple. Rather, it containedcochineal, identified using HPLC, and a large amount of calcium,as indicated by XRF, which suggests that chemically this materialmay be similar to the pigment under the name Purple lake. In ourstudy, we have chosen to use Indian purple as the name for thecopper-containing colorant, which has been used mostly in worksbegun in the Caribbean and in the Adirondacks.

Homer applied purple paint in small touches and broad washes. Heused it descriptively and to heighten the visual intensity as a colorcomplement to yellow-green, as prescribed by Chevreul. In England,Homer accented the fishing nets with Indian purple (Cu variety) inTynemouth Priory 1881. Homer used Purple lake in Girl with a Hay Rake(1878) for a small touch of deep color in her bodice. He chose Purplelake for the shadow in a fisherman’s trousers below the oar in Casting,Number 2 (1894). This is an interesting use of color in shadows, whichHomer considered with great perception. He used this colorant in thedark cloud at the top of Sketch for Hound and Hunter, which was paintedin the same year. It was used as a translucent wash for the tree trunksin The Milk Maid (1878); it was also used as a wash in Girl Carrying aBasket (1882) though here over blue paint and also in Incoming Tide(1883); later it appears on a rock in A Good Shot (1892).

In the early to mid-1880s, Homer used purples mixed from indigoand red lakes in the British watercolors. In Native Huts, Nassau (1885),Homer used a mixture of charcoal grey and red lake for a cool purpletone to paint the roof of the hut and the clouds. In North Woods Club,


Adirondacks (1892), Homer washed red lake, now entirely faded,across blue mountains undoubtedly producing a layered purple hueon the peaks (Figure 19.2). It is likely that only a limited number ofmixed purples were detected in AIC works due to fading of red lakes. Afaded edge on Casting Number Two (1894) (Figure 19.7) illustrates theextent of chromatic change that can occur when the red component ofmixed purples made from indigo and red lake fades.

19.3.6.3 Payne’s Grey. Payne’s grey is a dark blue-grey neutraltone mixed from blue, red and black—often indigo, cochineal lake,and ivory black. This color could be purchased as a manufacturedhue or mixed on the watercolor palette. XRF analysis (which wouldonly give indications of the presence of ivory black through de-tection of high calcium and phosphorus), occasionally aided withRaman spectroscopy (that can positively identify indigo and ivoryblack), in combination with microscope examination indicatedHomer occasionally used such mixtures to paint skies in his sea-scapes. While changes in manufacturers’ formulations preclude de-termining if each hue was prepared commercially or by the artist,two hand-written notations on Homer’s extant watercolor boxes in-dicate positions for Payne’s grey (note —Gr – either Payne’s grey orcharcoal grey, Portland box), and one cake was found in the Port-land box. In Tynemouth Priory, England (1881), Homer used Payne’sgrey or his own mixture to depict the cloudy sky. In this work, the

Figure 19.7 Photomicrograph of a faded edge on Casting Number Two, 1894, il-lustrating fading of the red component of mixed purples made fromindigo and red lake. The color is preserved only where the pigmentswere protected from light by the mat board.

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red and blue pigments in the sky, now visible only with the aid of amicroscope, have faded, leaving only the ivory black particles vis-ible. This has rendered the sky grey inaccurately suggesting severeweather and a darker mood than Homer likely intended. Initially,the sky would have appeared bluer and less ominous. In Prout’sNeck, Breaking Wave (1883), Homer used a mixture of cerulean blue,red lake, and ivory black to make a grey color.

19.3.6.4 Browns. Four pans in the Portland box contain an or-ganic brown earth pigment that can be called either Vandyke brownor Cologne earth.z Vandyke brown is sometimes considered to beslightly lighter toned than Cologne earth, but the distinction betweenthe two pigments is not well-defined. Both pigments are deep, semi-transparent colors. Early manuals on watercolor painting warned ofthe difficulty of applying Vandyke brown to large areas.30

19.4 CONCLUSIONS

The analysis of the colorants Homer used for his watercolor paintinghas complemented the visual study of the works and provided aconcrete way of looking at the evolution of the appearance of hisoeuvre. In light of the extensive analysis of a significant corpus of hiswatercolors, it is now possible to put the results of analysis of the twoextant watercolor boxes in better context. Indeed, we can now deter-mine that the contents of the watercolor boxes are not a true re-flection of Homer’s use of colorants in his paintings. While there arecakes of pigments which he did employ in almost all his works, theboxes also contain cakes of colors he rarely used such as Indian yellowand green earth, suggesting these boxes might have become storagefor unused or reserved cakes rather than conceived of as palettes.

This study also allowed us to identify the changes in Homer’spalette over time. Most noticeable is a reduction in his reliance onzinc white and a general move to include more transparent and free-flowing pigments. However, Homer never fully abandoned opaquepigments, but reserved them for small touches or applied them diluteor in mixtures so as to preserve the overall transparent character ofhis compositions.

zWhile we have identified them as Vandyke brown, it is not possible to distinguish Vandykebrown from Cologne earth. Winsor & Newton refers to Cologne earth as a calcined form ofVanDyke (sic) brown, see Taylor 1887, 61. Feller and Johnston-Feller suggest that the two pig-ment names should be considered synonymous. Vandyke brown is distinguished from otherbrown pigments by its solubility in alkali. For further information on this solubility difference,see ref. 26, p. 175.


A strong command of pigment properties and behaviors combinedwith an intense sensitivity to truth in nature drove Homer to suchnuance and specificity in his mastery of the watercolor medium.Today, artists are still in awe of Homer’s skill and visit museums tostudy the master’s technique. As well as providing an overview ofavailable watercolor materials in America in the late 1800s, the newknowledge accumulated in this study will undoubtedly open fruitfulwindows into Homer’s art and studio practice.

APPENDIX 1: INSTRUMENTATION

XRF spectroscopy. AIC: an air-path Bruker ArtTAX microfocus XRFsystem with collimator 1.5 mm, excitation tube with Mo target and Heflushing for enhanced detection of light elements was used. NGA: anair-path Kevex 0750A spectrometer with a liquid nitrogen cooled Si(Li)detector (beryllium window) equipped with 6 mm collimators and aBaCl2 or Mo secondary target was used.

Raman microscopy. AIC: a Jobin Yvon Horiba Labram 300 confocalRaman microscope was used, equipped with three lasers operating at532, 632.8 and 785.7 nm. Power at the samples was kept very low(never exceeding 1 mW) by a series of neutral density filters in order toavoid any thermal damage.

Micro-FTIR spectroscopy. AIC: a Bruker tensor 27 FTIR spectro-photometer with mid-IR glowbar source and Hyperion 2000 micro-scope. NGA: a Nicolet Nexus 670 bench spectrophotometer was used,equipped with a Continumm microscope. The samples were com-pressed in a diamond cell (Spectratech). Two hundred scans werecollected. At both institutions samples, were analyzed in transmissionthrough the microscope after compression in a diamond cell, at 4cm�1 resolution.

Optical microscopy. AIC: a Leica MZ12 stereomicroscope was usedfor close examination of the surface at 8–32�. NGA: a Wild stereo-microscope was used at 5–50�.

ACKNOWLEDGEMENTS

At AIC we thank the A. W. Mellon Foundation, The Community Asso-ciates of the Art Institute of Chicago, The Fred and Susan Novy FamilyFoundation for their generous support and Lisa Backus, Emily Warner,and Harriet Stratis for their valuable contributions to the research.

YS and BB deeply appreciate the assistance Lisha Glinsman pro-vided in reviewing XRF data and Charles Brock’s helpful comments.

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Abigail Gerdts, Director of the Goodrich-Homer Art Education Project,is also thankfully acknowledged.

REFERENCES

1. B. Berrie, Y. J. Strumfels and C. Tolocka, The Broad Spectrum, ed. H.K. Stratis and B. Salvesen, Archetype, London, 2002, pp. 101–107.

2. W. Homer, M. Tedeschi, K. Dahm, J. Walsh and K. Huang,Watercolors by Winslow Homer: The Color of Light, The Art Instituteof Chicago, Chicago, 2008.

3. A. Gerdts, Director, Goodrich-Homer Art Education Project, per-sonal communication (email to Kristi Dahm, dated June 12,2013).

4. Watercolors in The National Gallery’s collections can be viewed atimages.nga.gov and those in the AIC collections can be viewed atartic.edu/aic/collections/homer/artwork (accessed June 11, 2013).

5. R. Newman, C. Weston and E. Farrell, J. Am. Inst. Conserv., 1980,19, 103.

6. S. M. Halpine, Stud. Conserv., 1996, 41, 76.7. P. C. Beam, Winslow Homer at Prout’s Neck, Little Brown, Boston,

1966, p. 221.8. J. Walsh, American Traditions in Watercolor: The Worcester Art

Museum Collection, ed. S. E. Strickler, Worcester Art Museum,Worcester, Mass, 1987, pp. 45–65.

9. M. E. Chevreul and J. Spanton, The Laws of Contrast of Color: AndTheir Application to the Arts of Painting, Decoration of Buildings,Mosaic Work, Tapestry and Carpet Weaving, Calico Printing, Dress,Paper Staining, Printing, Illumination, Landscape, and Flower Gar-dening, &c., Routledge, Warnes, and Routledge, London, 1859.

10. L. Goodrich and J. W. Beatty, Winslow Homer, Pub. for theWhitney Museum of American Art by the Macmillan Co, NewYork, 1944, p. 222.

11. J. K. Delaney, E. Walmsley, B. H. Berrie and C. F. Fletcher,Scientific Examination of Art: Modern Techniques in Conservationand Analysis, The National Academy Press, Washington, DC, 2005,pp. 120–136.

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13. J. Kirby, National Gallery Technical Bulletin, 1977, 1, 35.14. D. Oltrogge, http://www.museenkoeln.de/ausstellungen/wrm_0802_

impressionismus/download/Oltrogge_VIS-Spectroscopy_eng.pdf,Koln, 2008 (accessed 6/10/2013).


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16. A. Claro, M. J. Melo, J. S. Seixas de Melo, K. J. van den Berg,A. Burnstock, M. Montague and R. Newman, J. Cult. Herit., 2010,11, 27.

17. M. J. Melo and A. Claro, Acc. Chem. Res., 2010, 43, 857.18. F. Casadio, M. Leona, J. R. Lombardi and R. P. Van Duyne, Acc.

Chem. Res., 43, 782.19. C. L. Brosseau, F. Casadio and R. P. Van Duyne, J. Raman Spec-

trosc., 2011, 42, 1305.20. J. S. Taylor, A descriptive handbook of modern water-colour pig-

ments: illustrated with seventy-two colour washes skillfully graduatedby hand on Whatman’s drawing paper with an introductory essay onthe recent water-colour controversy, Winsor & Newton, London,undated (c. 1900/1909).

21. H. Seward, Manual of Colours, Showing the Composition andProperties of Artists’ Colors, with Experiments on Their Permanence,George Rowney & Co., London, 1889.

22. I. Fiedler and M. Bayard, Artists’ Pigments: A Handbook of TheirHistory and Characteristics, ed. R. L. Feller, Cambridge UniversityPress, Cambridge, 1986, 1, pp. 65–108.

23. G. Gates, Stud. Cons., 1995, 40, 201.24. R. Newman, J. Am. Inst. Conserv., 1979, 19, 42.25. N. S. Baer, R. Joel, R. L. Feller and N. Indictor, Artists’ Pigments:

A Handbook of Their History and Characteristics, ed. R. L. Feller,Cambridge University Press, Cambridge, 1986, 1, pp. 17–36.

26. B. Berrie, Artists’ Pigments: A Handbook of Their History andCharacteristics, ed. A. Roy, National Gallery of Art, Washington,1997, vol. 2, pp. 191–217.

27. N. Eastaugh, V. Walsh and T. Chaplin, The Pigment Compendium,Elsevier, Amsterdam, 2004.

28. R. J. Gettens and G. L. Stout, Painting Materials: A Short Encyclo-paedia, Dover Publications, New York, 1966.

29. (Late) M. Wendell Upchurch, Manager of Education and Tech-nical Services for Winsor & Newton in the U. S., private com-munication, 1993.

30. G. B. Allen, Water Color Painting: A Book of Elementary Instructionfor Beginners and Amateurs, Lothrop, Lee & Shepard Co, Boston,1898, p. 56.

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A Vibrant Surface: Investigating Winslow Homer's Watercolors