The unusual panel construction - the second board from the left is a very thin fillet - is visible in both the right-hand image, taken in raking light, and the central x-ray. The x-ray also shows numerous wood supports on the reverse, which have since been removed. The small areas of impasto on the jewels, cord and fabric stand out very well in x-ray due to the use of pigments containing lead and it is also evident that the fur collar on the cape was originally painted slightly longer than it now appears.

© National Portrait Gallery, London