Artworks made of plastic - how can we keep them for the future?
An EU-funded research project at Statens Museum for Kunst in cooperation with The School of Conservation is examining the issues in order to aid in preserving our Works of Unique National Importance (ENB-works).
Plastics are used in all aspects of daily life. They can be moulded into a dizzying array of forms, shapes or sizes. But plastics are not only found in household items, shoes, handbags and building materials, but also in works of art. At Statens Museum for Kunst we have many artworks made either partly or wholly of plastics: acrylic paint, expanding foam rubber, cast acrylic sheets, polyester, and fiber glass are just some of the many plastic types found in the museum's collection. Among them are also ‘Works of Unique National Importance’ (ENB-works).
The problems with plastics
All materials degrade with time. The problem with plastics is that they degrade at a much faster rate than most other materials. Each polymer has its own characteristic modes of degradation, but three of the most common causes are: exposure to heat, light and chemicals.
Many plastics contain plasticizers, which helps to create flexible and elastic objects. When the polymer starts to degrade, these plasticizers are pushed out towards the surface of the object - often creating sticky, yellowing and crumbling surfaces.
Limitations to current conservation practice
Traditionally, art conservation is divided into two categories: active and preventive conservation.
Conservation of plastics demands an active ‘preventive conservation’ policy. This means keeping the light levels low, as well as controlling the temperature, humidity and airborne pollutants while on exhibition and in storage. Plastics in storage are best kept in cool, dark, stable surroundings with adequate ventilation, as some plastics emit acidic gases.
But in reality ‘preventive conservation’ of plastics presents an even greater challenge: once degradation has begun it will continue, although at a slower rate, even if the artwork is placed in cool surroundings with very little or even no light.
Active conservation involves the actual conservation treatment of an art work, such as repairing damaged parts, as well as removing degrading pollutants, such as dust, from the surface.
How to keep the surfaces clean?
Keeping the surfaces clean, without accelerating the degradation process, is vital to the longevity of plastics – which are very reactive to chemicals, cleaners, and even water. At the same time, they often are very electrostatic, attracting dust and particles. So how do we clean the surfaces of plastics?
This is especially critical for painted surfaces, such as one of our ENB-works by Per Kirkeby A Romantic Picture from 1965. This painting, done in enamel and acrylic paints, presents a special ‘future’ challenge to the conservator: can this surface be cleaned and what methods should we use to do it? This question is the essence of our research project in plastics.
Louise Cone, Conservator, Contemporary Art