TU Delft: Looking between the hidden layers of The Night Watch

Additional canvases can be added to the back of a painting to strengthen it. In the past, these lining canvasseswere glued to the back of a painting using a mixture of beeswax and resin. The lining canvas of The Night Watch was attached to Rembrandt’s masterpiece in 1975, following the infamous knife attack. Shearography analysis will be carried out to increase understanding of the extent to which the 46-year-old support canvas is affixed to the original 17th-century canvas on which Rembrandt painted The Night Watch, and to determine whether the bonding between the two canvases is still adequate. Shearography is an optical measurement technique that can measure deformations at the micro- and nano scale using laser illumination and a specific camera. By briefly heating the painting from the front or the back by only one or two degrees Celsius, and then scanning them with a special shearography instrument, researcher Andrei Anisimov can locate the loose and weak spots of paintings. Andrei Anisimov: “It is an honour to research the Night Watch and thus contribute to its successful restoration.”



Captain’s pants
The main point of interest is the pants of Captain Frans Banninck Cocq, in the foreground of the painting. In 1975, that part of the painting was severely damaged by a confused man with a knife. The Night Watch was subsequently restored to its former glory by restorers, by attaching a lining canvas behind the original canvas. Anisimov,Groves and Tao will therefore focus their research on the status of this part of the painting and compare it with other, undamaged parts of the Night Watch. The first inspection will be done from the back of the painting, to minimise the risks to affect the paint pigments.



Wall painting of St. Christopher in a church in Zeeland
This year, Anisimov and his colleagues already used this shearography instrument to inspect the 15th-century wall painting in the picturesque village of Nisse, Zeeland. They discovered that shearography can reveal delaminations in more detail and exclude the human factor when compared with traditional tapping tests.

Shipyard
Normally, this research set-up is not found in the museum, but for example in a shipyard or at an aerospace company. There, new materials such as composites for the hulls of ships are put to the test. Thanks to the method, the researchers can detect manufacturing defects and the location of damage in these materials without having to saw the material into pieces. In that research, Anisimov and his colleagues aim to broaden the application of shearography inspection to complex materials and shapes as curved parts of aeroplanes or thick marine composite materials.