NOTES ON EXECUTION TECHNIQUE AND STATE OF CONSERVATION

Technique of execution

The fresco fragment from the ancient Palazzo Pretorio, was detached together with the entire painted plaster surface in the second half of the 19th century, and transferred onto a new support made of a metal grate drowned in gesso treated with sizing.

The painting appears to have been executed according to the traditional buon fresco, technique, with colors mixed in water and applied to the still wet plaster. Consequently, during the drying phase, the calcium hydrate contained in the malt undergoes a carbonation process and, absorbing the colors, fixes them to the support surface rendering them more resistant to external agents. Only the saint's mantle, painted with azurite, was applied directly to the dried plaster without the usual preparatory red mission.

Analysis has revealed at least three days of painting, or three not very large areas of malt that the painter had to paint before the plaster dried completely.

In particular, the hands and face show traces left by the carbon tacks used in transferring the drawing to the plaster by means of the dusting.method. The dusting technique, commonly used in all of Piero della Francesca's mural paintings, consisted of making pin holes along the outlines of the full-scale preparatory drawing done on cardboard which, placed over the plaster painting surface, was tamped down with a cloth sac containing carbon powder. The powder, penetrating through the pin holes, left an image on the wall of the composition to be reproduced in the fresco, making the work easier for the artist. It can be observed on the hands of the saint that the under side of the cartoon was placed against the surface so that the paper was not properly smoothed down and left its print on the fresh plaster.

In the case of the pastoral staff, on the other hand, it is possible to see the marks left by direct incision.

The painter used gold for the halo of Saint Ludovico, composed of a series of luminous rays.

State of Conservation

The 19th century detachment of the Saint Ludovico was not a completely successful operation, as is demonstrated by the precarious state of conservation of the painting and the numerous deep breaks in the plaster.

The present appearance of the fresco is to be attributed, however, to a more recent restoration.

It is quite likely that, after the detachment, the missing plaster in the fragment was replaced and the entire fragment then enclosed within a false frame, of which there are a few traces in the lower part of the painting.

Later the frame and the plaster replacements were removed and the fresco filled out with neutral zones in preparation for insertion in the current wood frame.

The initial diagnostic analyses identified a vinyl resin based superficial fixative that had been applied to the entire painting in order to consolidate the exfoliated paint. Under the fixative the analysis revealed the presence of shellac, used in all likelihood during the detachment operation and not completely removed from the surface during the removal of the protective cloths. Between the two fixatives there are substantial areas of repainting, effected in order to hide the many abrasions and gaps in the paint. Over time these have undergone alteration, provoking a darkening of the original colors. The azurite in the mantle shows numerous abrasions with wide gaps in the pigment, and its current color is the result in large part of previous restorations.