How could slavery, an institution, be represented visually? In Witnessing Slavery: Art and Travel in the Age of Abolition, Sarah Thomas addresses this question in its late eighteenth- and early nineteenth-century Atlantic contexts by studying artists’ representations of the crucial synecdoche of the institution—enslaved people themselves. She concentrates on artists who traveled to slave colonies in the Americas and promoted their work for its truthfulness, thanks to their firsthand observations. Chapters concentrate on individual artists: Agostino Brunias, John Gabriel Stedman, James Hakewill, Jean-Baptiste Debret, Augustus Earle, and Johan Moritz Rugendas. With the exception of Stedman, all of them had already traveled on the Continent as artists. Only two and one-half of these artists were British (Hakewill, Earle, and the Dutch-English Stedman), though British antislavery was the major catalyst for their work. Their presentations ranged from shrewdly anti-abolitionist genre and landscape images for slave-owners (Brunias and Hakewill), through ambivalently antislavery narrative illustrations (Stedman), to worldly, not to say voyeuristic, surveys of a slave society (Debret, Earle, and Rugendas). That enslaved people, as such, could be subjects for artists could not be taken for granted in European visual culture. None of Thomas's artists, with the partial exception of Stedman via William Blake, are treated in Marcus Wood's Blind Memory: Visual Representations of Slavery in England and America 1780–1865 (2000) and The Horrible Gift of Freedom: Atlantic Slavery and the Representation of Emancipation (2010), but these books have the complementary virtue of drawing on a rich body of vernacular illustrations, from newspapers’ woodcuts to postage stamps.

All five of Thomas's artists are well known in art history, and she engages in respectful conversation with the relevant literature, particularly T. J. Barringer, Gillian Forrester, and Barbaro Martinez-Ruiz, Art and Emancipation in Jamaica: Isaac Mendes Belisario and his Worlds (2007); Kay Dian Kriz, Slavery, Sugar and the Culture of Refinement: Picturing the British West Indies, 1700–1840 (2008); and Amanda Bagneris, Colouring the Caribbean: Race and the Art of Agostino Brunias (2018). In comparison with these authors, Thomas is less interested in visually racial aspects of slavery in the Americas and more interested in artists’ agendas, strategies, and attitudes toward sustaining or criticizing slavery. Brunias's apparently autonomous African-Caribbeans on Dominica in the 1770s, happily dancing and marketing, contradicted the developing abolitionist critique of slavery as dehumanizing. William Blake's 1796 engravings of Stedman's watercolors from his five years as a counterinsurgency mercenary in 1770s Suriname, with their combination of narrative, natural history, and horrific scenes of torture, gave the soldier's account credible authority in abolitionist circles. Hakewill's estate views of Jamaican slave plantations in the 1820s naturalized them as part of the landscape, in the era of amelioration. The richest chapter deals with Debret, Earle, and Rugendas in Brazil, the oldest, largest, most complex, and most long-lived, but no longer richest, slave society in the Americas. All three showed gruesome pictures of public torturing, but these images were visually overwhelmed by innumerable genre scenes of enslaved people across a broad social spectrum in every aspect of Rio's life. Here Debret's watercolors, rather than the more usually reproduced prints from his three-volume, Voyage Pittoresque et Historique au Brésil ou séjour d'un Artiste Français au Brésil depuis 1816 jusqu'en 1831 (1834–1839), are particularly impressive. Rugendas, exceptionally, toured the countryside and illustrated enslaved people both at work and at home.

Rugendas's exceptional breadth is a reminder of striking absences from the visual archive of slavery. Most genre and figural art bearing on enslaved people had urban, not plantation settings, so it largely ignored the basis for the institution of slavery in the Americas, namely to provide unpaid labor for the commercial production of agricultural staples. Instead, it studied either the miseries or the comforts that enslaved people experienced thanks to their legal owners. The iconographic staples for artists representing slavery were people dancing, people being tortured, and people being sold—not people working.

For most of the early modern period in the Atlantic World, the sugar mill embodied slavery as a synecdoche of the entire plantation complex that required enslaved labor. Only in the last quarter of the eighteenth century did the people who were enslaved become subjects for visual representation. This recognition coincided with the rise and mobilization of antislavery sentiment, as abolitionism. Abolition had several objects, some of them contradictory to the elimination of slavery: lessen the torture of enslaved people, make their living conditions sustainable, regulate against atrocities in the trans-Atlantic slave trade, and end that trade. Abolition of the trans-Atlantic slave trade in 1807 did not end slavery, nor the sale of slaves: people could still be legally bought within and between colonies. People who hated the institution of slavery hoped that it would end in a few decades, but few called for its immediate and outright abolition until the 1820s. Many hoped that abolition of the African slave trade would force slave owners, out of capitalist self-interest, to create a work force whose willingness to cooperate in the reproduction of labor would eventually enable their transition to wage labor. The continental expansion of slavery in the United States disproved that hope; conversely, the development of Cuba into the foremost sugar colony relied on the Atlantic African slave trade into the 1850s. The confoundment of abolition was most evident with its success: despite slavery's injustices, when Parliament did abolish slavery in British colonies, it compensated the owners, not the enslaved—with a fund of about four billion dollars in today's money.

Thomas has written, Emily Lees has designed, and the Paul Mellon Centre for the Study of British Art has produced, a beautifully effective book. Large-size, perfect color reproductions of paintings and prints on a remarkably readable and viewable heavy-stock paper make it possible to survey the art of slavery for our own determinations.