Netherlands Institute for Conservation, Art and Science

A fundamental molecular understanding of oil paint degradation

Oil paintings are subject to slow ageing processes that can harm their appearance and structural integrity. In this project, the research focus will move from the characterisation of materials to the quantification of processes; using fundamental chemical science to make an impact on the preservation of oil paintings.


Exposure to water, whether as environmental humidity or as cleaning solutions, is known to strongly influence the rate of oil paint degradation. In this project, we study in molecular detail how water influences oil paint degradation processes, and quantify their sensitivity to humidity fluctuations and paint restoration practice.


To achieve this goal, a combination of multiple advanced infrared spectroscopy methods will be applied to paint materials. These techniques will make it possible to study the effect of water on:

  • the release of metal ions from pigment particles, and the rate of metal ion migration in the oil;
  • the structure of the ionomeric oil polymer with potentially reactive metal ions;
  • the timescale of hydrolysis of polymer ester groups, that results in oil network breakdown and metal soap crystallisation.


This research will provide crucial information on the influence of water on degradation kinetics, to support museums around the world in the development of improved conservation strategies and optimal indoor climate conditions that minimise oil paint deterioration.



NICAS / Joen Hermans

Schematic illustration of the three water-sensitive processes occurring in oil paint that can lead to paint degradation that form the basis of this project.

Principal researcher

Joen Hermans (University of Amsterdam)

Type of project


Participating researchers

  • Sander Woutersen
  • Katrien Keune
  • Piet Iedema
  • Lambert Baij

Institutions involved

  • University of Amsterdam
  • Rijksmuseum

Expected completion date

September 2022

Funded by a NWO Veni grant

Published by  NICAS

9 May 2019