Next time you look at a painting on a gallery wall, why not take a moment to think about it in a different way? Consider it less as a flat image and more as a three dimensional object, with a back as well as a front, and multiple, complex layers sandwiched together in between.
Imagine the diversity of the materials present : maybe Italian poplar or oak from a Bavarian forest, glue made from rabbit skins, walnut, poppy or linseed oils, pigments produced from local clays or from minerals mined from the mountains in Afghanistan. There may be arsenic, mercury and other poisonous materials present or beautiful blue paints made from cobalt glass, now faded to grey.
Although it probably appears as though paintings never change but just silently hang there, it is interesting to consider that should, for example, an 18th Century artist see their works now, they would be dismayed or even really shocked at the changes that have occurred over the centuries [especially if their name was Joshua Reynolds – more about him another time]. They would notice changes in the tonal qualities between the darkest and lightest passages, cracking of the paint layers, possibly fading of some of the pigments and even restoration of damage. They might even discover that things that used to be invisible [e.g- the preparatory drawing or compositional changes that they subsequently painted over] are now visible on the surface, because the upper paint layers have increased in transparency with age.
Why not get as close to a painting, as security measures will allow, and think about the paint and the materials and techniques employed – it may prove very revealing.