Vermeer's Palette: Verdigris

Origin, History and Characteristics

(Grünspan, vert-de-gris, verderame)

Verdigris, a copper-based green pigment, has been produced through various methods since antiquity. Historically, one common technique involved exposing copper to acetic acid vapors. For instance, Pliny the Elder described suspending copper plates over fermenting grape vapors, allowing the acetic acid to react with the metal and form a green patina, which was then scraped off and ground into pigment.

During the Middle Ages, another method entailed burying copper strips attached to wooden blocks in dung after treating them with acetic acid. The warm, moist environment facilitated the formation of verdigris, which was later collected and processed.

In eighteenth-century Montpellier, France, a notable production technique involved stacking copper plates in clay pots filled with distilled wine. The acidic content of the wine induced the development of verdigris crystals on the copper surfaces, which were periodica lly harvested.These traditional methods highlight the diverse approaches to synthesizing verdigris, reflecting its historical significance and the evolving practices in pigment production.

Verdigris has been historically significant in painting due to its vibrant hue and unique properties. It was widely used in medieval and early modern art, valued for its brilliant green color that could range from a bluish to a yellowish green depending on its preparation and the binder used. Verdigris was commonly derived by exposing copper to acetic acid, often in the form of vinegar, under controlled conditions.

While verdigris offered a striking color, it presented certain challenges for painters. It is chemically unstable and highly reactive, which often led to discoloration or degradation over time. In oil painting, verdigris could cause the paint to darken or even turn brown due to its sensitivity to moisture and its tendency to react with sulfur-containing compounds. Despite these drawbacks, its strong tinting strength and transparency made it a favored pigment for glazing techniques, where it could create luminous effects when layered over lighter tones.

Green glazes of verdigris were commonly used in oil paintings of the fifteenth to seventeenth centuries (fig. 1) for the depiction of saturated green colours of drapery and foliage. Today, these glazes are often covered with a brown layer and sometimes the whole glaze has become brown. Verdigris was consistency mixed with the same pigments; lead white, lead-tin-yellow and yellow ochre. Leonardo da Vinci had was not in favor of the use of verdigris in oil painting given that the pigment has a certain tendency to fade. He wrote around 1492:

LOOKING OVER VERMEER'S SHOULDER

The complete book about Johannes Vermeer's and 17th-century fine-painting techniques and materials

by Jonathan Janson | 2020

Enhanced by the author's dual expertise as both a seasoned painter and a renowned authority on Vermeer, Looking Over Vermeer's Shoulder offers an in-depth exploration of the artistic techniques and practices that elevated Vermeer to legendary status in the art world. The book meticulously delves into every aspect of 17th-century painting, from the initial canvas preparation to the details of underdrawing, underpainting, finishing touches, and glazing, as well as nuances in palette, brushwork, pigments, and compositional strategy. All of these facets are articulated in an accessible and lucid manner.

Furthermore, the book examines Vermeer's unique approach to various artistic elements and studio practices. These include his innovative use of the camera obscura, the intricacies of his studio setup, and his representation of his favorite motifs subjects, such as wall maps, floor tiles, and "pictures within pictures."

By observing closely the studio practices of Vermeer and his preeminent contemporaries, the reader will acquire a concrete understanding of 17th-century painting methods and materials and gain a fresh view of Vermeer's 35 masterworks, which reveal a seamless unity of craft and poetry.

While the book is not structured as a step-by-step instructional guide, it serves as an invaluable resource for realist painters seeking to enhance their own craft. The technical insights offered are highly adaptable, offering a wealth of knowledge that can be applied to a broad range of figurative painting styles.

LOOKING OVER VERMEER'S SHOULDER
author: Jonathan Janson
date: 2020 (second edition)
pages: 294
illustrations: 200-plus illustrations and diagrams
formats: PDF
$29.95

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CONTENTS

1. Vermeer's Training, Technical Background & Ambitions
2. An Overview of Vermeer’s Technical & Stylistic Evolution
3. Fame, Originality & Subject Matte
4. Reality or Illusion: Did Vermeer’s Interiors ever Exist?
5. Color
6. Composition
7. Mimesi & Illusionism
8. Perspective
9. Camera Obscura Vision
10. Light & Modeling
11. Studio
12. Four Essential Motifs in Vermeer’s Oeuvre

13. Drapery
14. Painting Flesh
15. Canvas
16. Grounding
17. “Inventing,” or Underdrawing
18. “Dead-Coloring,” or Underpainting
19. “Working-up,” or Finishing
20. Glazing
21. Mediums, Binders & Varnishes
22. Paint Application & Consistency
23. Pigments, Paints & Palettes
24. Brushes & Brushwork

The green colour made of rust of copper, Green made of copper, even when this colour is mixed with oil, loses its beauty like smoke if it is not quickly varnished. It not only goes up in smoke, but if it is washed with a sponge dipped in simple, ordinary water, the verdigris will disappear from the panel on which it has been painted, especially in humid weather. This comes about because verdigris is made from salt, which dissolves easily in rainy weather, and especially when it is bathed and washed with the sponge…

"In his encyclopedia of 1694, Pomet noted that French unrefined verdigris was mainly exported to Holland. After Pekstokk had refined it into a purer product it was re-exported to France. Thus Pomet claimed that all the distilled verdigris on sale in Paris actually came from either Holland or Lyon.

Although verdigris was sometimes recommended as a drier in red lakes as well as blacks, De Mayerne’s sources note that this green pigment would muddy the colour of a red lake; instead they suggested using white copperas (zinc sulphate).

"Yet, until well into the seventeenth century, it appears that artists seldom purchased this remarkably pure ready-to-use distilled verdigris. A price-list of pigments purchased by painters in the De Mayerne manuscript only mentions 'ordinary' verdigris and not the distilled pigment. Inventories of four seventeenth-century Dutch shops specializing in the sale of artists' materials suggest that there can hardly have been any demand for distilled verdigris from painters. These shops had increasingly taken over the sale of pigments from the apothecaries."^{M.H. van Eikema Hommes, "Verdigris Glazes in Historical Oil Paintings: Instructions and Techniques," in Discoloration in Renaissance and Baroque Oil Paintings. Instructions for Painters, theoretical, Concepts, and Scientific Data (dissertation, 2002), 85.}

In seventeenth-century Holland, verdigris was not among the most expensive pigments, such as ultramarine and high quality red lake, which ran into several guilders an ounce, but among the mid-price pigments, which included indigo and yellow lake.^{M.H. van Eikema Hommes, "Verdigris Glazes in Historical Oil Paintings: Instructions and Techniques," in Discoloration in Renaissance and Baroque Oil Paintings. Instructions for Painters, theoretical, Concepts, and Scientific Data (dissertation, 2002), 86.}

In modern times, verdigris has largely fallen out of use due to its instability and the availability of more stable green pigments, such as chromium oxide green or phthalo green. Nonetheless, its historical significance and its impact on the visual character of many historical artworks remain a subject of interest for art historians and conservation scientists.

Verdigris in Vermeer's Painting

Verdigris has been found in various painting by Vermeer, once over a layer of natural ultramarine of the tablecloth of Maid and Mistress, which was orinally meant to have a green color, and again under a layer of brilliant blue paint of jacket of Woman in Blue Reading a Letter. Ige Verslype, who restored the latter work in 2010–2011, hypothesized that the underlying layer of verdigris was meant to intensify the upper layer of ultramarine of the woman's blue jacket. The conservator Robert Wald reported that the cloth (fig. 2) which drapes over the front of the massive table in the foreground of Vermeer's The Art of Painting was underpainted in virdigris and then glazed with a semi-transparent layer of ultramarine blue, giving its present teal color. Recent studies have discovered low amounts of copper. which would indicate the presence of virdigris, in some of Vermeer’s underpaints in A Lady Writing, Mistress and Maid and Woman Holding a Balance, where it seems to have been used as a drier and not a pigment.

Vermeer’s use of verdigris as a drier reveals his meticulous approach to managing time and texture in his painting process. Recent analysis of Woman Holding a Balance shows that the underpaint layer of the tablecloth contained copper-based additives, likely verdigris, which accelerated the drying of slow-curing pigments.^{E. Melanie Gifford, Dina Anchin, Alexandra Libby, Marjorie E. Wieseman, Kathryn A. Dooley, Lisha Deming Glinsman, John K. Delaney, "First Steps in Vermeer’s Creative Process: New Findings from the National Gallery of Art," Journal of Historians of Netherlandish Art 14:2 (Summer 2022)} This allowed Vermeer to move quickly through the preparatory stages without waiting for the paint to dry completely, enabling him to proceed with subsequent layers efficiently. The evidence comes from advanced imaging techniques such as XRF copper maps, which highlight areas of the painting rich in copper. These maps show that copper was concentrated in the underpaint but largely absent from the final layers. Microscopic analysis of paint samples confirmed that the copper in the underpaint was evenly dispersed, typical of verdigris used as a drier, rather than present as distinct particles of pigment. This deliberate addition of copper-containing material to the underpaint stage suggests that Vermeer tailored his materials to meet specific functional needs.

Vermeer’s technique also had aesthetic implications. The quickly applied underpaint, visible in the textured brushstrokes beneath the smooth surface, contributed to the final composition's depth and subtlety. By using less drier in the final paint, he ensured that these layers dried more slowly, allowing him to work wet-on-wet and achieve a refined, leveled finish. This careful balance between the quick-drying underpaint and the slow-drying final layers underscores Vermeer’s thoughtful approach to both the practical and artistic challenges of his craft.