Museum objects are often highly complex and composed of materials with varying properties, some of which may have changed as a result of ageing and/or conservation treatments. Research into defining sustainable environmental conditions by balancing energy cost and risk to these vulnerable objects has mainly focused on experiments in laboratories with new, single materials or on computer modelling, but only to a limited extent on actual objects. This paper presents a method to collect empirical data from a large group of decorated wooden panels in order to investigate the effects of humidity fluctuations on these objects and relate them to their material properties and construction. Wooden panels were chosen as they are regarded to be particularly sensitive to fluctuations in relative humidity. The fluctuations may cause the wood to shrink and swell and can result in open glue joints, cracks, and deformation of the panels as well as losses and cracks in the decorative layers. Empirical data are scarcely available as yet but are essential to study relationships between material properties, type of construction, damage, and as input and validation for modelling and experimental studies. The method, referred to as the Rijksmuseum Study, was performed on a group of 300 objects from the furniture and paintings collections of the Rijksmuseum.