Measuring photostability through glass: the application of microfading testing to the study of framed pastel artworks

Abstract

Paper‐based heritage objects on exhibition are typically framed using a transparent glazing material such as glass or acrylic. This often makes the task of measuring their light fastness a difficult one since cultural institutions may have unframing restrictions, especially for large‐format objects. However, a testing programme recently conducted at the National Museum in Krakow has revealed that in certain cases it is possible to obtain colorant stability information directly from a framed object. Microfading testing results are reliable if the distance from the object to the protective glazing is adequate to allow proper illumination and collection of reflected light. This paper presents a case study of six large‐format pastels on paper by Stanisław Wyspiański, one of the most outstanding and versatile artists at the turn of the twentieth century in Poland. Some of the orange and pink areas showed higher sensitivity to light with fading rates that remain within the Blue Wool 1–2 range. The objects have been classified according to the light sensibility of their colorants, and this information has allowed development and implementation of exhibition guidelines that serve to minimise the degradation associated with museum illumination. In addition, scientific imaging, microfading data and computer analysis of the images have allowed virtual representation of the potential colour changes that these artworks may experience as a result of uncontrolled and long exposure to gallery illumination.

Micro fading test for textile single yarns: a new methodology applied to the Reformation Tapestry to assess its sensitivity to light

“…We use a glass slide to properly fix and flatten the sample. Microfading framed and glazed objects through glass has already been outlined in previous studies [20][21][22].…”

Impact of Protective Glass on Photodegradation of Ink-Jet Printed Documents

“…Another example is the application of carboxylate-alumoxane coating, which was found to be non-destructive to coated paper [20] . Paper-based objects are usually framed using transparent glazing like glass or acrylic [21] . When choosing the type of protection, it is best to decide for the one that minimally influences the structure of the material which is being protected [20] .…”

A new lighting method for cultural materials using selective chromatic light

“…Light sensitivity of painting materials and other works of art has been well investigated in past [10][11][12][13] and recent studies. [14][15][16][17][18][19] Other related investigations tried to predict the impact of light exposure in terms of fading or general decay. [20][21][22][23] Particular interest was addressed to painting materials, where pigments and dyes are the components most subjected to fading or decay due to their ability to absorb light.…”