X-rays are a type of radiation which can be used for analysing aspects of a work of art not visible to the naked eye. X-rays can pass through most solid objects, but they are obstructed by certain materials. The heavier the atoms of a substance, the more resistance it has to X-rays. Pigments containing heavy metals such as lead and mercury appear white in an X-ray image or ‘X-radiograph’, as do the metal parts used in the construction of a painting’s support.
X-radiographs are used for revealing changes that may have occurred at different stages in the development of a painting: overpaint, traces of previous restoration and damage to the paint layer and support.
The X-radiograph of the Tallinn painting reveals that the original painting is generally well-preserved. There are minor losses in parts of the paint layer, mainly in the areas of panel joints and near the lower edge. Later overpaint on the Tallinn painting, most likely from the 19th century, is also clearly shown by X-radiography. There is one small area of paint loss – covering part of the small, half-naked child in the lower-right corner – where the paint appears to have been intentionally scratched off; this was probably been carried out at the same time as the application of overpaint in order to make this area more ‘proper’.
X-radiography enables us to ‘see through’ the painting, visualising all the layers of the object simultaneously. One can see the structure of the panel and reinforcement system of the boards at the back side simultaneously with paint layer.