Visualisation of watermarks
The determination of backing material, writing materials and drawing materials is just as much a part of our service as the visualisation of paper structures, watermarks and backs – even with laminated objects, glued backs and flat mountings on passe-partout cardboard. For this purpose, we use a specialised camera system with which this information can be collected and read out. Especially for objects laminated on strong cardboard, we work with our own developments that guarantee optimal results.
X-ray fluorescence examinations
xatra gmbh has extensive expertise in the art technological analysis of works of art on paper.
We use our own developments to identify traces of transfer and make faded or erased information visible. Based on extensive statistics of comparative data, we determine reliable information by analysing the art-technological structure and on the basis of secondary characteristics, which give our clients the necessary certainty in the evaluation of works of art. Particularly in the case of incomplete or missing provenances, the comparison with our extensive databases is the only way to obtain objective results beyond purely expert assessments.
With the help of a spectrophotometer, the colour value of a colourant can be quantitatively determined on the basis of its reflection spectrum in the visible light range between 380 nm and 730 nm. The sample to be examined is illuminated with visible light. The sample material interacts with the radiation and absorbs or reflects the visible light in a specific way. As a result, it appears coloured. The reflected light, which is characteristic for a certain colourant, is measured with the help of the photometer and stored in the form of a reflection curve. This reflection curve represents the dependence of the intensity of the reflected light on the wavelength. The comparison with the reference measurements stored in a database usually enables the assignment to the respective colourant or the colour mixture used.