I have been reminded repeatedly that an object of value, whether financial or sentimental, tends to have a history, even if unknown to the owner. As an art historian, conservator of oil paintings, and maker of handmade frames, I want - and am determined, so far as is possible - to find out the history of the work of art with which I have been entrusted. So often that history is there for a skilled practitioner: in the image, in the pigment, and in other detail, underneath layers of dirt, opaque varnish and other discolouring. One has to look - and look again - as one sets out to establish how pictures looked in their original state.