The wood grain and the panel join can be seen in the x-ray image in the centre. The brushwork is clearly visible, particularly the paint applied wet-in-wet in the fur. Black underdrawing can be seen in the face and fur in the infrared reflectogram on the right. The strong outlines of the features and jewels are often reinforced with secondary marks, while the lines in the cheeks, temples and hair were applied more freely.
© National Portrait Gallery, London