Netherlands Institute for Conservation, Art and Science

NICAS Colloquium

28Mar2019 12:00 - 13:00


The next edition of the NICAS Colloquium takes place on Thursday, 28 March 2019, from 12:00 to 13:00 in Conference Room B of the Atelier Building (Hobbemastraat 22, Amsterdam).


The chair of this colloquium will be Fréderique Broers (Rijksmuseum, University of Amsterdam).


The following presentations are scheduled for this edition of the NICAS Colloquium:


Challenges in maintaining a scientific system for microscope colour calibration at the Rijksmuseum

Susan Smelt

The Rijksmuseum developed the online Paint Sample Database in which all research on paint cross-sections mainly from their collection of paintings, frames and objects is digitized. For the database there is a strong need for accurate colour capture of the cross-sections since it enables meaningful comparisons: within an artwork (comparing changes and alterations), and across different artworks. Ideally such comparisons should not be dependent on a particular microscope or institution. In the absence of any existing solution for reflected light microscopy colour management, the Rijksmuseum developed and carefully tested a modular open-source system for accurate microscope colour correction to ensure the most precise and reproducible imaging of paint cross-sections. Recently some challenges were faced; the saved white balance in Bright Field and Dark Field was not correct anymore. A colour shift was noted, and research was started into the possible causes of this shift. The author would like to ask the audience for their opinion.

Susan Smelt works as paintings conservator at the Rijksmuseum. She is currently the project coördinator of the large scale ‘full body’ research project of the Nightwatch by Rembrandt starting this July in the galleries.


Deciphering Rembrandt’s impasto via identification of unusual plumbonacrite by multi-modal Synchrotron X-ray Diffraction

Victor Gonzalez

Rembrandt is renowned for his impasto technique: thick paint with outstanding rheological properties, increasing his paintings light-reflecting textural properties. To achieve this, he combined lead white pigment (mixture of cerussite PbCO3, and hydrocerussite Pb3(CO3)2(OH)2) with an organic binding medium, but the exact formulation used by Rembrandt remained a mystery. This research aimed at elucidating the composition and microstructure of Rembrandt’s impastos at the microscale. Paint micro-samples collected on artworks from the collections of the Rijksmuseum, the Mauritshuis and the Louvre were structurally probed using Synchrotron X-ray diffraction. Nanocrystallites of a rare lead compound, plumbonacrite Pb5(CO3)3O(OH)2, were detected in areas of impasto, constituting the fingerprint of Rembrandt’s recipe. By confronting Synchrotron results with historical sources, we will propose chemical pathways for the crystallization of this specific crystalline phase and new insights into Rembrandt pictorial practice.

Victor Gonzalez is a post-doc researcher at the Rijksmuseum, where he is involved in the scientific analysis of Old Masters materials and techniques, with a focus on ancient inorganic pigments.


Thursday, 28 March 2019


12:00 – 13:00 hrs


Conference Room B, Atelier Building
Hobbemastraat 22, Amsterdam

Published by  NICAS