According to WPB, the publication of an article by the Australian Department of Defense on 29 May 2026 highlighting the artistic work of Commander Andrew Littlejohn has unexpectedly drawn attention to a niche but historically significant application of bitumen. While the article itself focuses on artistic practice and personal expression through painting and printmaking, it references a copper plate etching created by the artist. For specialist’s familiar with traditional etching methods, that detail raises an interesting technical question: what type of bitumen or bitumen-derived material was most likely used in the production process?
The original report does not identify the material applied to the copper plate, nor does it describe the composition of the etching ground. However, based on established printmaking practices, historical documentation, conservation literature, and the materials commonly available to contemporary artists, it is possible to make a reasonable technical assessment of the bituminous substances that may have been involved.
Copper plate etching remains one of the oldest and most respected forms of intaglio printmaking. The process relies on protecting selected areas of a metal plate while exposing others to acid. In order to accomplish this, artists traditionally apply a protective coating known as an etching ground. The role of this coating is simple but essential: it must adhere to the metal surface, resist acid attack, remain stable during handling, and allow precise removal with engraving tools. For centuries, one of the most effective materials used in such coatings has been asphaltum, a naturally occurring bituminous substance.
If the Australian artwork referenced in the report was produced using traditional methods, the most likely candidate is not a paving-grade petroleum bitumen such as penetration grade 60/70, 80/100, or viscosity grade VG30. These products are designed for road construction and industrial applications. Their rheological properties, temperature sensitivity, and handling characteristics make them unsuitable for fine-art etching. Instead, artists typically rely on refined asphaltum varnishes or specialized printmaking grounds formulated specifically for engraving and etching.
Historically, one of the best-known materials in this category was Bitumen of Judea. This natural asphalt, sourced from deposits associated with the Dead Sea region, gained widespread use among European artists from the eighteenth and nineteenth centuries onward. The material possessed several characteristics that made it attractive for etching applications. It formed a durable film, adhered well to copper surfaces, and provided strong resistance against acid solutions commonly used in printmaking studios.
The material's origins are significant. Natural bitumen deposits around the Dead Sea have been documented for thousands of years. Ancient civilizations collected floating bituminous masses for construction, waterproofing, medicine, and artistic purposes. By the nineteenth century, processed forms of these materials were being exported to Europe and incorporated into artistic techniques ranging from etching to early photographic experiments.
From a materials science perspective, asphaltum behaves differently from modern paving bitumen. Artistic asphaltum products are generally purified, processed, and blended with solvents or resins to produce a coating with predictable behavior. The objective is not structural performance, as would be required in highway construction, but chemical resistance and surface stability. This distinction is critical when evaluating what might have been used in the Australian etching process.
The mechanism through which a bituminous etching ground functions is relatively straightforward. A thin layer of asphaltum-based coating is applied to a polished copper plate. Once the coating hardens, the artist scratches lines through the surface using an etching needle. These incisions expose the underlying copper. The plate is then immersed in an acid bath, traditionally ferric chloride or another etching solution. The acid attacks only the exposed copper while the bituminous coating shields the remaining areas. After sufficient depth has been achieved, the coating is removed and ink is pressed into the etched lines. The final image is then transferred onto paper using a printing press.
This protective role explains why bitumen became an important material in artistic production long before modern road paving emerged as its dominant market. In many respects, the requirements of an etching ground parallel those sought in industrial protective coatings: adhesion, durability, chemical resistance, and stability under controlled conditions.
Several countries continue to manufacture artist-grade asphaltum products. Contemporary suppliers in the United Kingdom, France, Germany, Italy, the United States, and Australia provide specialized formulations for printmaking studios and fine-art schools. These materials are often sold as liquid asphaltum varnishes, hard grounds, soft grounds, or components of custom etching mixtures. Although their volumes are insignificant compared with global paving-grade bitumen consumption, they represent a specialized niche where bituminous materials retain cultural and artistic relevance.
The Australian context provides additional clues. Most professional printmaking workshops in Australia use commercially prepared etching grounds sourced from established art-material suppliers. These products generally contain refined asphaltum blended with waxes, resins, and solvents. Such formulations provide consistency and eliminate many of the handling difficulties associated with raw natural bitumen. Therefore, if Commander Littlejohn used a contemporary printmaking studio, it is highly probable that a prepared asphaltum-based ground rather than crude natural bitumen was employed.
It is also important to distinguish between natural asphalt and petroleum-derived bitumen in this context. Both materials contain heavy hydrocarbon fractions, but artistic applications typically prioritize consistency and controllable performance. Modern printmaking materials are often engineered to provide predictable behavior under workshop conditions. As a result, many products used today are modified versions of traditional asphaltum formulations rather than untreated natural deposits.
From the perspective of the bitumen industry, artistic applications occupy a fascinating but largely overlooked corner of the market. Discussions surrounding bitumen normally focus on roads, roofing, waterproofing membranes, industrial fuels, and infrastructure projects. Yet the material possesses a cultural history extending far beyond engineering. Museums, conservation laboratories, and printmaking studios continue to work with bituminous substances that share chemical ancestry with products used in transportation infrastructure.
Interest in these applications has increased among historians and conservation specialists seeking to understand historical artistic techniques. Analysis of nineteenth-century prints often reveals the presence of bituminous compounds within protective coatings. Conservation experts studying these works must understand how such materials age, oxidize, and interact with environmental conditions. Their findings contribute not only to art preservation but also to broader knowledge regarding the long-term behavior of bituminous materials.
Although the Defense article was not intended as a discussion of industrial materials, it inadvertently highlights a connection between art and petroleum-derived substances that remains relevant today. The copper etching referenced in the report serves as a reminder that bitumen's history extends into fields rarely associated with the energy sector. Long before penetration grades, viscosity classifications, and polymer-modified binders became standard terminology, artists were already employing bituminous materials as technical tools within sophisticated production processes. The exact formulation remains unknown, the technical requirements of copper plate etching strongly favor artist-grade asphaltum products derived either from natural asphalt traditions or modern refined equivalents. This assessment aligns with contemporary printmaking practice, historical precedent, and the chemical characteristics required for successful acid-resistant coatings.
The case offers a useful reminder that bituminous materials continue to serve functions extending beyond infrastructure and construction. Even in an era dominated by discussions of sustainable roads, advanced binders, and energy markets, specialized artistic applications remain part of the broader story of bitumen and its diverse range of uses.
By WPB
News, Bitumen, Printmaking, Copper Etching, Asphaltum, Art Materials, Dead Sea Bitumen, Natural Asphalt, Acid Resistance, Heritage Conservation
