IPERION HSIntegrating Platforms for the European Research Infrastructure ON Heritage Science

Stopping colours of cultural heritage objects from fading

Stopping colours of cultural heritage objects from fading is one of the most important assignments of preventive conservation. Knowledge about the pigments or colorants used and the assessment of the photo sensitivity of the objects are key information for the long them preservation of the colour information of an object.

In order to improve the proficiencies in this field of work, researchers from the Riksantikvarieämbetet (The Swedish National Heritage Board) made use of the IPERION CH ‘access to facilities’ program to visit the Rathgen-Forschungslabor (Rathgen Research Laboratory of the National Museum in Berlin, Prussian Cultural Heritage Foundation), one of the access provides within the ARCHLAB scheme.

During the visit which took place in November 2017, researches of the both institutions exchange experiences and discussed possibilities for collaborating more closely within the field of Raman spectroscopy and microfading in cultural heritage applications.

Raman spectroscopy is an instrumental analytical method frequently used for the identification of pigments. This method necessitates an archive of spectral reference from pigments in order to identify pigments in a sample from an object. Enlarging the archive of spectral reference relevant to the analysis cultural heritage is one of the persistent tasks of each laboratory working in this the domain. With the on-going development of virtual data hubs in the domain of heritage science, the hopes are high that in the near future such spectral reference will be provided freely in an online repository. As a result of the visit both institutes were able to enlarges their archive of spectral reference.

Microfading is a method to assess the photo sensitivity of cultural heritage objects. The sensitivity of the objects surface is compared to a standard material with well-known photo sensitivity. This material is the so called Blue Wool reference material. Calibration materials from various manufacturers exist and are discussed among experts as being a potential source of discrepancies in estimation of the objects photo sensitivity. Both institutions’ microfading instruments were set up in the same room and a range of samples and reference standards were measured concurrently. Fruitful discussions unfolded about instrument specifications and modifications, Blue Wool standard limitations, environmental influences, data handling and result reporting. Both institutions benefited tremendously from this excellent exchange and hope that this will spark to future collaborations and initiate international cooperation to improve the framework for preventive conservation of cultural heritage.