The dovetail joints and glued canvas
Two walnut dovetail joints were inserted into the back of the panel to one third of its thickness, to stop the spread of the eleven-centimeter split that is visible on the front of the painting.
We don’t know exactly when they were inserted; nor do we know when the first one disappeared. To compensate for its loss, a piece of canvas was glued into the notch and along the length of the split in the wood. Various tests conducted since then have confirmed the stabilization of the split.
“3”
The figures 1, 2, 3 and 4 appear at four points down the length of the panel. They indicate the position of four wooden cross braces that were fixed to the oak frame maintaining the panel in its original shape.
Sensors have now been fixed to the cross braces to monitor (in real time) any warping of the panel and prevent any damage to the painting.
The flight holes
The small holes all over the back of the poplar panel are traces of the passage of xylophagous (wood-boring) insects.
The edges of the panel (which must have been slightly planed down) show a network of tunnels too, but only flight holes are visible on the back.
There is no danger of such infestation today, as the Mona Lisa is kept safe inside a closed display frame.
The edging paper
An edging paper is visible down all four sides of the poplar panel. It was glued to the panel at some point in the past, to avoid any contact between the painting and the glass frame. Traces of previous edging papers are also visible; their application even altered the color of the wood.
“4”
The figures 1, 2, 3 and 4 appear at four points down the length of the panel. They indicate the position of four wooden cross braces that were fixed to the oak frame maintaining the panel in its original shape.
Sensors have now been fixed to the cross braces to monitor (in real time) any warping of the panel and prevent any damage to the painting.
“2”
The figures 1, 2, 3 and 4 appear at four points down the length of the panel. They indicate the position of four wooden cross braces that were fixed to the oak frame maintaining the panel in its original shape.
Sensors have now been fixed to the cross braces to monitor (in real time) any warping of the panel and prevent any damage to the painting.
“1”
The figures 1, 2, 3 and 4 appear at four points down the length of the panel. They indicate the position of four wooden cross braces that were fixed to the oak frame maintaining the panel in its original shape.
Sensors have now been fixed to the cross braces to monitor (in real time) any warping of the panel and prevent any damage to the painting.