'Technical Examination' is the first step in the conservation process. Technical examination allows conservators to see damage to the painting that might not be visible to the naked eye in normal light, and also to see areas which may have been filled or retouched during past conservation treatments.
HMS Hector in normal and UV light: A close-up of one of the flags on the painting of HMS Hector, showing the paint surface in normal light (left), and showing the same area under UV light (right). The very dark areas following the decorations on the flag and the mast are modern retouching, while the areas that appear washed out are the original paint.
Mary Clarke in raking light: A close-up of the portrait of Mary Clarke under raking light (light which is sharply angled to show surface texture), showing cracks and quilting to the paint surface. You can also see the texture of the canvas underneath the paint in some places.
Hull and the Humber in normal and transmitted light: A close-up of the painting 'Hull and the Humber', showing a detail of ships on the Humber in normal light (left), and showing the same area with transmitted light, where the light is shone through from the back of the painting (right).
In the left-hand picture, you can see areas of loss which have been filled, and a few areas where the losses have not been filled, but in the right-hand picture this is even more visible, with the edges around the filled areas showing as light rings, and the unfilled areas as bright patches.
HMS Hector under 20x and 40x magnification: A close-up of the paint surface of the painting of HMS Hector under magnification. Under 20x magnification (left), you can see cracks and pits in the paint surface, as well as dirt and varnish residues.
Under 40x magnification (right), you can see areas of retouching, where the newer paint sits on top of the varnish, as well as various sizes of cracks, varnish residues, and areas where the paint surface is thinner.