Entomology for Dummies
Sometimes the demonstration of how useful, and surprising, the collaboration between art and science in the study of a painting can be, goes beyond common expectations.
A few years ago, in the “Olive trees” artwork that Van Gogh painted outdoors in 1889, a grasshopper was found trapped in oil layers. The insect was almost invisible to the naked eye given its very small size, and at first it was mistaken for a small leaf. Despite a consultation with a biologist, it was not possible to determine in which season the painting was made, however, it was possible to assert that the insect ended up on the canvas already dead, since no signs of movement were detected.
A new study on the same work has also revealed the presence of particles of dry leaves and numerous information on the technique used by the painter. The XRF and FTIR techniques have in fact shed light on how Van Gogh proceeded layer by layers and on how he preferred the combination of complementary colours, aware of the harmony they would have created as a whole.
A curious aspect of studying the works carried out outdoors is the possibility of discovering information on the nature of the subject of the painting, beyond what the painting itself represents and wants to communicate. With the masters of the so-called School of Barbizon we witness the spread of painting en plein air, which will be the stylistic code of the painters generally referred to as Impressionists and Post-Impressionists. Landscapes, trees and rivers become the protagonists of the works together with the subjective vision of the performer, who often proceeds quickly and with large brushstrokes; the boundary between preparatory sketch and finished work becomes blurred!
Thanks for example to letters and biographies, about the habits of painters, we are in possession of a lot of information. We know, for example, that Daubigny had prepared his study on a boat and that Monet did the same, as well as usually painting from his own garden. At the same time, many objects for outdoor painting were invented, including kits with transportable easels, while the development of photography was an important support tool in capturing images of atmospheric phenomena, to be reworked with ease in the studio.
Diagnostic investigations allow us to know more about the “experience” of a work, about how the painter chose colours, how he gave quick brushstrokes before the light changed and how some works were retouched even after years.
In the most curious cases, like that of Van Gogh, they also give us the pleasure of feeling, at least for a moment, transported inside the painting, among the leaves moved by the mistral.
Do you want some more examples? The sprouts of leaves on the canvas of Gustave Caillebotte‘s “Laundry hanging to dry on the banks of the Seine” and the grains of sand on Armand Guillamin‘s “The sea at Saint-Palais”. This is also living art … as well as living on art !!
Cats… they hide everywhere and pop up when you do not expect them! For example, in this painting by Frans Floris in which a cat is visible only thanks to Reflectography, as it is not present in the final version. 
A very violent lightning struck Verrocchio’s golden ball that overlooks the dome of the Florence Cathedral, threw it off and dropped it where a plaque still remembers the point of impact. The impression was enormous. It was seen as a clear sign of the incoming end of the world.
In the preparatory drawing, visible in the reflectograpy made by Art-Test, there is a sort of crane drawn on the right side of the lantern, a crane which then disappears in the finished painting. So we can assume that the crane was visible at the time of the drawing but not when the painting was concluded. This detail could therefore help with the dating both as regards its conception, and therefore the realization of the first underdrawing, and as regards the finished artwork.
It is also known that, for example, a crane was designed specifically for the lantern. But the drawing made by Gherardo Mechini in 1601 shows a large scaffolding that surrounds the whole structure. So either the Carmine altarpiece was built when the restoration works were over, or it was at the time of another near-end of the world.
