David McDiarmid was one of the first Australian artists to use synthetic plastics as a principal medium in his art. His choice reflects the increasing pervasiveness of plastics in everyday life during the 1970s and the growing availability of plastics specifically produced for art and design purposes. Just like traditional artist materials such as oil paint, bronze and stone, plastics provide artists with a range of visual and material properties, however, unlike many of these traditional materials, plastics rarely have a lifespan greater than fifty years and often times the lifespan of particular plastics may be significantly less. For a conservator, whose primary role is the preservation and conservation of works of art for current and future generations, the use of plastics by artists such as McDiarmid presents new and interesting challenges.
The most immediate challenge is the correct identification of the plastics used by the artist. Knowing which plastics an artist has used in an artwork is important because it can help determine the best methods for preservation and display. Unfortunately, the word ‘plastic’ may be used to refer to a wide variety of natural or synthetic materials each with their own different properties. For works that appear to contain a variety of plastics, such as McDiarmid’s ‘shower screen’ collages, the task of identifying the material is all the more important because many different types of plastics have a similar visual appearance. In these situations conservators must rely on other types of analysis to correctly identify plastics.
One such method of identifying different plastics is by Fourier transform infrared spectroscopy (FT-IR). With this method IR (infrared) radiation is passed through a sample. Some of the infrared radiation is absorbed by the sample and some of it is passed through. The resulting spectrum represents the different wavelengths which were absorbed by the sample, creating a molecular fingerprint. Like a human fingerprint, no two unique plastics produce the same infrared spectrum and as such we can recognise the different fingerprints of the different types. Normally, destructive sampling (removing material from an artwork) would be necessary to carry out this type of analysis; however, in this instance the NGV has been fortunate enough to receive from David McDiarmid’s executor and guest curator of the exhibition, Dr Sally Gray, a collection of studio materials from the artist’s estate.
Analysis of these materials revealed that McDiarmid’s quilts and collages are composed of many different plastics including: cellulose nitrate, cellulose acetate, poly(ethylene terephthalate) PET, poly(vinyl chloride) PVC, polycarbonate and polyethylene. Moreover, several of the plastics which looked the same (e.g. the coloured glitter sheets) had different chemical compositions. For example, some of the holographic films were made of PET and some were made of PVC. Identifying the presence of PVC can be particularly useful because unlike PET, which is a relatively stable material, PVC releases acidic vapour as it ages and this can promote the deterioration of the artwork and of other works in its vicinity. Similarly, some plastics react differently to different types of solvents and so identification assists conservators in determining the best options for treating the artwork and the best methods for storing it when it is no longer needed for display.
Although the first synthetic plastics were developed over a century ago and were used by artists from the early 1920s onwards, it is not until the 1960s that the use of plastics in art becomes widespread. The availability of David McDiarmid’s studio materials and the opportunity to focus on his work in the lead-up to the current exhibition provided the NGV with the perfect opportunity to analyse McDiarmid’s materials and develop appropriate strategies for the conservation of his art.
In the next two conservation blog posts we will look at the cleaning and treatment of David McDiarmid’s, Thinking of You, 1990, and a recreation of plastic gum leaves in My Sydney, 1978, both from private collections and now on show in David McDiarmid: When This You See Remember Me.
David McDiarmid: When This You See Remember Me is open until 31 Aug at NGV Australia.