I found out how he got the gold paint

Chemists from the Rijksmuseum and the University of Amsterdam uncovered and published findings in a study released in July 2024 in Heritage Science, explaining how the renowned 17th-century Dutch painter and printmaker Rembrandt achieved the distinctive “gold paint” effects in his works. Utilizing advanced spectroscopic techniques, PhD students Fréderique Broers and Nouchka de Keyser successfully mapped the presence of pararealgar (a yellow mineral) and semi-amorphous (orange/red) pigments in a section of his iconic oil painting The Night Watch from 1642. The gold pigments reveal traces of arsenic sulfide mixed with colors: Rembrandt employed this technique for the golden threads in the embroidered coat and the gold embroidery on the double sleeves of Lieutenant Willem van Ruytenburch, who is a central figure in the painting alongside Captain Frans Banning Cocq.

But is this chemical compound dangerous? It all hinges on the dosage: according to the Toxin and Toxin Target Database (T3DB), arsenic sulfide can be extremely harmful if ingested or even inhaled in certain doses. This exposure likely affected Rembrandt and other artists of his era, potentially leading to central nervous system depression, as well as damage to the bone marrow, lungs, liver, and kidneys, with an associated cancer risk. For comparison, just 600 micrograms per kg of body weight of arsenic trioxide (a compound similar to sulfide) is sufficient to be lethal to an individual of average health.

The discovery made by the Rijksmuseum and the University of Amsterdam is not the only ‘dangerous’ secret related to Rembrandt’s painting The Night Watch. The project Operation Night Watch, which commenced in 2019 to unravel the mysteries surrounding this masterpiece, has revealed other intriguing elements, including additional compounds of arsenic and sulfur found in Lieutenant Van Ruytenburch’s clothing (following X-ray fluorescence examination). Given these findings, the researchers concluded that artists active in 17th-century Amsterdam had access to a considerably broader range of materials than previously assumed.

Unveiling Rembrandt’s Gold Paint: A Modern Scientific Exploration

Introduction to Rembrandt’s Masterpiece: The Night Watch

Rembrandt van Rijn, the celebrated 17th-century Dutch painter, known for his brilliant use of light and shadow, created the iconic oil painting titled The Night Watch in 1642. This masterpiece, famed not only for its artistic merit but also for its complex historical context, has long captivated art historians and enthusiasts alike. Recent research by chemists from the Museum of the Rijksmuseum and The University of Amsterdam has shed new light on the techniques employed by Rembrandt, specifically his distinctive “gold paint” details.

The Chemical Composition of Rembrandt’s Gold Paint

In a groundbreaking study published in July 2024 in the journal Heritage Science, PhD students Fréderique Broers and Nouchka de Keyser utilized advanced spectroscopic techniques to analyze the pigments used in The Night Watch. Their findings revealed the presence of pararealgar – a yellow mineral pigment, alongside semi-amorphous orange/red pigments. Notably, traces of sulfur arsenic, a toxic compound, were found in the gold pigments used to depict the ornate clothing of Lieutenant Willem van Ruytenburch, a major figure in the painting.

Is Sulfur Arsenic Dangerous? Understanding the Risks

The discovery of sulfur arsenic prompts questions regarding its safety. According to the Toxin and Toxin Target Database (T3DB), arsenic sulfide can pose significant health risks if ingested or inhaled in hazardous doses. Historical evidence suggests that many artists of the time, including Rembrandt, may have been exposed to harmful levels of this compound, potentially leading to central nervous system depression and various organ damage. For context, an exposure of just 600 micrograms per kg of body weight of arsenic trioxide could be lethal for an average individual.

Insights from Project Operation Night Watch

The chemical analysis of The Night Watch is part of a larger initiative known as Operation Night Watch, which commenced in 2019. This comprehensive project aims to unravel the mysteries surrounding Rembrandt’s masterpiece. It not only investigated the gold paint but also discovered additional arsenic and sulfur compounds present in Lieutenant Van Ruytenburch’s attire through X-ray fluorescence examinations.

Implications of the Research

The findings highlight that artists in 17th-century Amsterdam had access to a broader palette of materials than previously understood, expanding our knowledge of art history and painting techniques during this period. The research indicates an intricate relationship between art and science, as these historical discoveries are made possible through modern analytical methods.

Benefits of Understanding Historical Pigments

1. Conservation Efforts: Knowledge of pigment composition can improve restoration techniques for protecting artworks against degradation.
2. Historical Context: By understanding the materials and methods used, we gain deeper insights into the artistic practices and daily lives of historical artists.
3. Educational Value: This research serves as an educational tool, highlighting the intersection of art, science, and history.

Modern Techniques in Art Conservation

Art conservation has evolved significantly with advancements in technology. Several modern techniques have emerged to analyze and restore artworks:

• Spectroscopy: Analyzing the various properties of pigments to understand their composition and interaction with light.
• X-ray Fluorescence (XRF): A non-destructive technique that allows for the identification of elemental composition in materials.
• Infrared Reflectography: Used to examine the underdrawings and compositional changes made by the artist.

Case Study: Analyzing Other Famous Artworks

The methodologies used in the analysis of The Night Watch can be applied to other significant artworks. For example:

Artwork	Artist	Key Technique	Notable Finding
The Last Supper	Leonardo da Vinci	Infrared Reflectography	Original composition variations discovered.
The Scream	Edvard Munch	X-ray Analysis	Revealed multiple versions painted over time.
Starry Night	Vincent van Gogh	Spectroscopy	Insights into non-traditional pigments used.

First-Hand Experience: Perspectives from Art Historians

Art historians emphasize the importance of interdisciplinary studies in the art world. Dr. Elena Marquette, an art historian at the University of Amsterdam, expresses: “Understanding the chemical composition of pigments not only informs us about the artists’ choices but also assists in preserving the integrity of their work for future generations.”

Conclusion

The collaboration between chemists and art historians through projects like Operation Night Watch enriches our understanding of Rembrandt’s techniques and the historical context of his work. The harmful components found in his paints raise awareness of the risks faced by artists of the past, while also shedding light on their sophisticated methodologies and material choices. The findings pave the way for enhanced conservation strategies that could prolong the life of great works of art, thus preserving cultural history for all to appreciate.