MICROCLIMATE FRAMES FOR PAINTINGS ON CANVAS A literature review with a case study from Nationalmuseum

Abstract: The use of microclimate frames for paintings has become more common in the past decades, and it is a good way of protecting climate sensitive paintings during transport, loans, and exhibitions. This study is a literature review that aims to describe the overall practice of mounting canvas paintings in microclimate frames, as well as describe practices at Nationalmuseum, Sweden’s largest art gallery, in more detail. The study is divided into two parts, the first one investigating when and why the use of microclimate frames is beneficial. This is done by looking at different agents of deterioration and how they affect paintings on canvas. The second part looks at how microclimate frames are used historically and today, with a focus on the protective effects for climate sensitive canvas paintings, and practical aspects such as material choices and aesthetic considerations. The case study from Nationalmuseum provides an example of what microclimate framing can look like in practice. In addition, conversations with conservators at Nationalmuseum as well as Gothenburg Museum of art have aimed to give a more comprehensive picture of framing practices. In studies microclimate frames have proved to have great effects in stabilising the internal microclimate of the frames and reduce relative humidity fluctuations around the objects. Added humidity buffers are rarely needed for small enclosures like microclimate frames and their addition has become less common. A concern is still the build-up of internally emitted volatile organic compounds. In more recent articles the mitigation of harmful compounds has been investigated. There is difference in opinion on how the degree of seal affects the mitigation, but several sources point to the use of pollutant scavengers, such as activated charcoal, as promising.