In Virgin of the Rocks, how is the Differences of the Description elucidated?
Compositionally, all the figures are slightly larger in the London painting than in the Louvre painting.  The main compositional difference between the two paintings is that while in the London painting the angel's right hand rests on his/her knee, in the Louvre painting the hand is raised, the index finger pointing at John.  The eyes of the angel are turned down in a contemplative manner in the London painting, but in the Louvre picture are turned to gaze in the general direction of the viewer.In the London painting, all the forms are more defined, including the bodily forms of the clothed figures.  The rocks are painted in meticulous detail, while the forms of the background in the painting in the Louvre are all more hazy.  The contrast between light and shade on the figures and faces in the London painting are all much sharper.  The faces and forms in the Louvre painting are more delicately painted and subtly blurred by sfumato. The lighting in the Louvre painting is softer and appears warmer, but this may be the result of the tone of the varnish on the surface. In keeping with their conservative handling of Leonardo's works, the Louvre version has not undergone significant restoration or cleaning. The Louvre painting remains much as it was in 1939 when Kenneth Clark lamented that "We can form no real conception of the colour, the values, or the general tone of the original, buried as it is under layer upon layer of thick yellow varnish. In the darks some mixture of bitumen has made the surface cake and crack like mud, and there are innumerable patches of old repaint all over the picture. All this must be borne in mind before we say that at this date Leonardo was a dark painter and an uninteresting colourist."
Another difference is in the colouring of the robes, particularly those of the angel. The London painting contains no red, while in the Louvre painting, the angel is robed in bright red and green, with the robes arranged differently from those of the angel in London. The London version contains traditional attributes missing from the Louvre version, the haloes and John's traditional cruciform reed staff. Davies says it is "not certain" if these details which are painted in gold are contemporary with the painting or have been added by a later artist. The details of the flowers are also quite different in the two paintings, with those in the Louvre painting being botanically accurate, and those in the London painting being fanciful creations.
right John haloes Louvre sfumato attributes Kenneth Clark