Chemical tests undertaken on this layer revealed that it consisted of repainting and that the binder was linseed oil, meaning that it had been added no earlier than 1750 (see fig.5). The landscape underneath was well preserved but was not entirely finished, which may have been one of the reasons why it was covered over.
In addition, an organic layer that was probably a varnish was also detected between the landscape and the overpainting, which functioned to separate the two. This information, together with solubility tests, supported the decision to remove the layer of black overpainting that had nothing to do with the original conception of the portrait (see fig.6).
The recovered landscape conforms to the colour range and forms of Leonardo’s evanescent landscapes despite obvious differences in the pictorial quality (see fig.7).
A surprising element, for example, located to the right of the figure, is the area of mountains taken from the autograph drawing by Leonardo of A rocky outcrop (ca.1510-15) in the Royal Collection, Windsor.