
In questo contesto, il disegno rappresenta qualsiasi figura tracciata utilizzando linee grafiche, incisioni o apposizioni su un supporto. Poiché può essere realizzato con mezzi semplici, permette all’artista di sviluppare una tecnica personale e offre ampio spazio per la sperimentazione, divenendo l’espressione più diretta e sincera del suo pensiero. A seconda del livello di dettaglio e complessità, il disegno è stato descritto in vari modi nella trattatistica artistica (schizzo, abbozzo, modello, bozzetto).
Per il san Bruno è noto un solo studio preparatorio. Si tratta della sanguigna con San Bruno inginocchiato, oggi al Victoria and Albert Museum di Londra, che mostra una prima idea più dinamica della posa del santo, poggiato col gomito sulla roccia mentre solleva il capo per ammirare la Vergine con un’espressione più di sorpresa che di rapimento estatico.
Look for corrections, afterthoughts and regrets in the main IR image on your left.
The modus operandi of Barbieri is mainly based on a direct drafting of color, almost abandoning the technique of preparatory drawing, limiting itself to short strokes, thin, not continuous and half dry for the realization of the contours of the face of some of the characters. This is also observable in some parts of clothing and drapery.
A fluid medium brush is, instead, used by Guercino in some steps, to create an artifice aimed at «detaching from the bottom» certain elements, in order to bring them into the foreground, in a sort of three-dimensional treatment. This is the case of the profile of the robe of the virgin, the right arm of the angel on the right and the two little cherubs on the top right.
There are small corrections, shots and modest repositioning performed in order to respond to its own aesthetic perception or greater anatomical accuracy. This is evident in the lowering of the top of the mountain in the background, in the profile of the child’s head, in the drapery at the bottom of the angel on the right.
The electromagnetic radiation that our eye can detect falls within a range of wavelengths, (“visible light”), from about 400 to 750 nanometers. Beyond these limits, the radiation becomes invisible to humans, but it still can interact in various ways with matter, e.g., through absorption, reflection, transmission, similar to what happens with visible light.
Infrared reflectography is an image acquisition technique that exploits the ability of infrared radiation (wavelength of near-infrared radiation 800-1000 nanometres) to penetrate below the surface of paint and visualize compositional paint changes. By taking advantage of this property, it is possible to observe – where present- preparatory sketches underneath the pictorial layer or to reveal pentimentos (afterthoughts, regrets) or to study changes made by the artist. The images that can be obtained are greyscale, where the lightest areas are those with chemical-physical characteristics that reflect infrared radiation either to a larger extent or completely. The sensitivity of the analysis depends not only on the chemical nature of the paint layers but also on their thickness. Infrared reflectography is pivotal in order to study the painter’s technique and the ‘idea’ at the origin of the painting: it is possible to observe elements that are not visible to the naked eye and to provide information on the evolution of the composition and construction methods of the artwork.