WhatsApp usAlthough oil paintings are most often associated with a canvas or panel, many have been composed on metal. Oil on copper stands out as a fine medium that emerged during the Renaissance and continued to be used across many styles and periods of art history.
But why did artists choose copper as a surface for their paintings? In this article, we will explore the origins of copper paintings as well as the unique qualities and the challenges these works present us with today. Our team will also share how our conservators carefully clean, restore, and protect delicate artworks on copper.
Above: a selection of oil paintings on copper including work by Nicolas Lancret, Benedetto Luti, Nicolaes Maes, Il Grechetto and Carlo Saraceni
Why Did Artists Paint On Copper?
It is generally established that oil on copper was a medium formed following the popular practice of enamelling metals, such as the ancient cloisonné method that applied pigment into areas of a pre-shaped pattern. This type of fine metalwork was long associated with power and wealth, as enamelled metal was reserved for a highly privileged few.
Above: detail from The Golden Age by Joachim Wtewael (1605) this oil on copper scene is taken from the opening of Ovid’s Metamorphoses – describing a time before silver, bronze, and iron
Whilst varieties of the craft can be found from the 8th century onwards, the true practice of oil painting on metal came into its own during the 15th century – likely due to the influx in availability of metal plates used in the new printing process and the shared knowledge that was now able to spread across renaissance Europe.
One of the most influential art historical records is Giorgio Vasari’s Lives of the Painters, Sculptors, and Architects which notes that Sebastiano del Piombo (1485-1547) was composing on a variety of metals such as silver, lead and copper in the first half of the 15th century.
Above: oil on copper portraits of Major-General Hans Willem, Baron van Aylva and his wife, mid 17th century
Copper plates could be purchased at around the same price as an oak panel and artists often chose them to add a unique quality to their work. In an era where aristocratic patronage ran the arts, they would have been looking for a new feature to make their paintings stand out in an increasingly crowded market.
Above: detail from The Artist’s Studio by Johann Georg Platzer, mid 18th century – this small oil painting on copper was designed for an art connoisseur’s cabinet
Artistic Qualities of Copper
Metal surfaces like copper and bronze could add a warm tone to a painting, but this was not the primary reason for using them. Copper paintings are usually small, you will frequently see this medium used for miniatures and cabinet paintings.
Above: The Virgin of Carmen and the Souls of Purgatory by Juan Francisco de Aguilera (1720) framed, unframed and seen from reverse – the painting is oil and gold leaf on copper, the frame is ebony, tortoise shell and silver
This is because their smooth surface is ideal for applying extremely fine details in a thin layer, uninterrupted by the texture of canvas or wood. The paint would not be absorbed on copper, making it appear brighter and bolder.
Copper was also seen as being immune to normal deterioration, such as warping panels. It was a strong and easily displayed material, much lighter and with less preparation time than the alternatives.
Above: the surface of a painting by Christian Seybold showing the smooth and precise composition that could be achieved on copper
Masters of the Medium
Who painted on copper? Many famous names used metal as a substrate for their paintings. Although most are traditional old masters, you may also find modern and contemporary artists who experiment with this unique medium.
Above: a series of grisaille portrait miniatures on copper by Jan Maurits Quinkhard, 18th century
Just a few of the artists who have examples of their work on copper include:
- Jan Breughel the Elder
- Rembrandt
- Guercino
- Ambrosius Bosschaert
- Joachim Wtewael
- El Greco
- Carlo Saraceni
- Jan van Kessel
- Correggio
- Osias Beert
- Bronzino
- Alessandro Allori
- Guido Reni
- Copley Fielding
- Vernet
- Chardin
- Juan Sanchez Cotán
Conservation Challenges
Whilst wood and canvas can expand and contract causing cracks and instability when left in an unstable environment, copper is much more stable and many examples have survived in good condition. However, the painted surface is a lot thinner and is most often damaged through abrasions and scratch lines. When a painting has survived for hundreds of years, it is not uncommon for it to have been accidentally damaged in this way, either through handling or environmental factors – such as close storage against other objects or rough packing materials.
Above: detail from a 16th century Netherlandish lamentation scene, this piece was small enough to be carried in a pocket for devotion, leading to the loss of the paint layer through handling and surface abrasion
Metal also faces its own challenges. Unlike other surfaces, it can corrode or present with rusting blemishes. High humidity and contact with water is the most likely reason for this to happen, whether this has happened historically or recently the results can linger and slowly decay the materials.
When the bond between the painter layer and copper weakens, you may begin to see blisters forming or areas of flaking. The structure of the painting can be compromised by the issues mentioned above as well as disasters like house fires and extreme fluctuations in temperature and humidity.
Above: detail from a baroque cabinet painting of Meleager and Atalanta, the red paint is flaking and there is embedded surface dirt and discoloured varnish in need of specialist treatment
Framing and Displaying Copper Paintings Safely
An oil on copper usually has a backing board to assist with stability, as any accidental bend could cause damage. It is also important that any framing materials have a low pH level to avoid chemical reactions with the metal.
The fragile surface may encourage you to place an oil painting on copper behind glass, but thought should be given to any issues that may occur due to trapped moisture between the glazing and painting when it is put on display. A microclimate can sometimes occur in this gap, so it is vital that the surrounding environment is stable and unlikely to encounter high humidity.
Above: Winter Landscape attributed to Jan Griffier (1680-1718) oil on copper, in an antique frame with backing board
Consider placing a humidity monitor in the room, the best levels would be below 60% relative humidity with an average temperature of 20 degrees celsius. If you have any concerns about your painting’s environment or framing, please contact our team for more advice and guidance.
How Conservators Restore Oil on Copper
Like most antique artworks, copper oil paintings have been finished with a protective varnish. This varnish can deteriorate and darken over time and the surface can also discolour due to pollutants like dust, soot, smoke and nicotine. Our conservation team clean paintings and remove varnish on a regular basis, as this is a key part of most treatment plans. However, their approach to oil paintings on copper is unique in comparison to canvas and panel artworks, as they cannot use anything aqueous – that is anything containing water or a solution that may prompt corrosion.
Above is an example of this work from our studio. Each painting is tested with sensitive measures in place, finding the best treatment for each individual artwork. It is important to remember that two paintings, even by the same artist or from the same era, may have different compositions in need of bespoke solutions. Surface cleaning, followed by varnish removal, is completed using a small cotton swab, swapped out every inch to avoid cross contamination.
Issues such as cracking, flaking or blistering paint are stabilised using precise application of adhesives, sometimes using a syringe to inject under the paint layer. Any flakes can be reapplied and if they are missing entirely, our conservators will level the lost area and retouch with a small amount of conservation-grade pigment.
Speak To Our Team
Please contact us to discuss your restoration project, no matter how complex it may seem. Our team of experts is happy to help.
As part of our service we offer a nationwide collection and delivery service as well as information on worldwide shipping to our studio. E-mail us via [email protected] or call 0207 112 7576 for more information.
