Netherlands Institute for Conservation, Art and Science

Glass sickness

Detection and prevention

This research is being conducted as a partnership between the Rijksmuseum and the University of Amsterdam with the involvement of other museums in the Netherlands and abroad. The topic is one of concern to all museums with glass collections. Approximately 10% of historical, post-medieval glass is unstable, resulting in the development of disfiguring visible changes. These changes range from the development of moist surface films to the formation of an entire network of cracks on the surface, known as crizzling. The latter extreme form of alteration renders the object opaque and unfit for display.

These effects, collectively known as ‘glass sickness’, are caused by faulty glass compositions.  It is known that an excess of alkali elements (sodium or potassium) and/or a deficit of alkaline earth elements (in particular calcium) make glasses susceptible to the irreversible chemical alteration of the glass surface. This alteration is brought about by no more than the interaction with atmospheric moisture over a long period.

The prime research goal is therefore to devise a means of determining which glasses in collections are susceptible before incontrovertible visible changes occur.  To this end, minute traces of ionic species on the glass surface are being analysed by ion chromatography.  These glass ‘corrosion products’ are simply removed by swabbing of small areas. A rigorously-validated, straightforward sampling/analysis protocol has been established. Thus, for the first time, the relative stability of individual glasses can be compared in a bid to ensure the long-term preservation of sensitive items in collections worldwide.


Fully crizzled and discoloured flagon with spout and ovoid body, height 13.9 cm, England, ca. 1700. Rijksmuseum.

Principal researcher

Guus Verhaar (University of Amsterdam, Rijksmuseum)

Type of project


Participating researchers

  • Maarten van Bommel (supervisor)
  • Norman Tennent (supervisor)

Institutions involved

  • University of Amsterdam
  • Rijksmuseum


Expected completion date

February 2018.

Partially funded by Eyewish Groeneveld.

Published by  NICAS

14 November 2017