This paper addresses issues surrounding the problem of ‘fogging’ glass in showcases. ‘Fogging’ is generally seen as an overall white bloom on the internal face of enclosed glass showcases. It may also be present in the form of white spots, a mottled appearance, or may even appear as a ghosting outline of writing or materials previously in contact with the glass. In some situations, crystalline deposits have been observed with the bloom or adjacent to silicone sealant. Initially the fogging was considered a cleaning problem for installation staff to deal with, but it has become obvious that this is a reoccurring issue, and is more sinister than first imagined.
A collaboration has formed between the National Gallery of Australia, Art Gallery of NSW and University of Technology, Sydney to investigate the cause of the fogging glass and to find a way to remove the problem permanently. We are concerned that the same factors affecting the glass may be damaging the artworks displayed in the cases.
So far, we have shared literature searches, tested the air quality inside showcases using Draeger testing kits and passive samplers taken samples of the different forms of fogging and crystalline deposits, examined them microscopically and analysed using FTIR and GCMS. We have also carried out practical cleaning tests to find non-toxic and effective ways to clean the glass. Further work underway includes obtaining samples of all materials included in the affected display cases to test their reactivity, and investigating the influence of environmental factors such as light, heat and high relative humidity.
At the conference we will present the work we’ve done to date and share our discoveries. We will also be seeking others interested in joining us in finding solutions. As many display cases have been custom built in museum spaces, retrofitting them with stable materials appears to be a more practical approach that to replace existing display cases altogether.