Microfade testing of light sensitive collections

Article Featured Image
Man with technical equipment and a decorative table Visiting conservation scientist, Bruce Ford, testing the light fastness of a painted table from the Lady Lever Art Gallery Siobhan Watts, Head of Conservation Science at the Conservation Centre, has news about some of the vital behind-the-scenes work that she does to protect our collections: "What do a watercolour by Burne-Jones, regimental colours, Native American quillwork moccasins, and silk furniture covers have in common? Answer - they are all sensitive to light, and will fade to a greater or lesser degree when they are on display. Conservators use their knowledge of the materials and colourants in these objects to advise on light levels and how to reduce their fading rate to a minimum. It is very difficult to predict exactly how quickly this will happen for a particular object, and the fading rate between different inks or pigments can vary greatly. This week at National Museums Liverpool's Conservation Centre we are working with a visiting scientist, using a new method that measures how quickly these objects will fade. Bruce Ford uses a technique called microfading to assess the light sensitivity of some key items from our collections. A tiny area (about 0.3-0.4 mm) on the surface of an object is faded to an imperceptible degree using a powerful but cold source of visible light and its colour change is tracked in real time using visible reflectance spectroscopy. conservators using technical equipment to examine a decorative table Bruce Ford and Siobhan Watts examining the different colourants during testing of a painted table from the Lady Lever Art Gallery The objects being tested include items to be displayed as part of the proposed redevelopment of the Lady Lever South End galleries, and the results will help us decide which objects to display and how much daylight we can let into the galleries in the new displays. The testing will also give us a good idea of how long we can leave items on display, before they will reach a 'just noticeable fade'. We’ll be testing some of the objects on display at the Museum of Liverpool, and also one of National Museums Liverpool's  most colourful and important objects, the Codex Fejérváry-Mayer. Watch this space for an update of the results!"