The conservation of Pieter Bruegel the Elder's Dulle Griet (Antwerp, Museum Mayer van den Bergh) at the Royal Institute for Cultural Heritage (KIK-IRPA) in Brussels was accompanied by scientific research of its original techniques and materials. Dendrochronology gives 1548 as the earliest possible date for the felling of the trees used in the panel's manufacture. Infrared imagery reveals a sparse, functional underdrawing, suggesting that Bruegel had carefully planned out the composition prior to painting. Indeed, few changes were made during execution and any such adjustments are minor. Cleaning brought to light Bruegel's exquisite brushwork. However, the paint layer is more translucent than at the outset and analysis shows that several colours have faded or darkened, including smalt and azurite-based blues and copper resinate greens. Infrared photography also helped reveal the signature and remains of the date, but it was only during cleaning that the full date was exposed: 1563