Numerous studies have been made to try
and understand the pictorial technique and material used by Caravaggio in
the executions of his paintings. The artist has left nothing in writing
and the testimonies of his contemporaries are scarce and imprecise regarding the
procedure he adopted to complete his work. We know however that Caravaggio loved to paint
from the model that he used a studio with light coming from the above and that he was very fast,
he could paint up to three heads in a single day. There are no unfinished paintings which remained
in an intermediate work phase, from which it would have been possible to trace, at least in part,
the various work phases, but there are figures, in some of his later paintings left by the
painter in an incomplete state of work. Based on this, of the few but precious tests
carried out, on the numerous and accurate scientific investigations as well as on
the careful study of the overlapping of the layers of color, we will try to retrace
the entire pictorial process of Caravaggio. The supports are always in
canvas, linen thick, and sparse, on average 12 by 12 threads per square centimeter. The preparation is dark, oily, a primer
with oil and pigment, mostly earth, with the addition of lead white and plaster.
Sometimes there is also sand in the dough. Much importance is given by the
artist to the color of the mestica, not only because it influences the finished work
but also because, often, Caravaggio kept large areas of it visible (without painting on it) or
perhaps by only spreading a light glaze over it. The cardinal points of the compositional
system, were quickly fixed with freehand incisions directly on the preparation.
From the signs detectable on his works, however, it is understood that these may not
have been a sufficient guide for the painting, more likely they seemed to be, as
intuited by Roberto Longhi in the 1950s, references to put the model back into position in
order to find, at each session, the right pose. It is practically an exclusive
procedure of this artist, who probably developed starting from the technique of carrying over the drawing by cardboard.
The sources say that Caravaggio did not draw but painted directly from reality without going
through an elaborated and studied drawing, as wanted by a consolidated
artistic tradition at the time. In practice, the artist drew by painting, the work is in fact done in a jet
and modified during the execution. He began by creating a graphic
layout with burnt shadow earth. Recent investigations carried out on “Cena in
Emmaus” preserved in the Pinacoteca di Brera seem to contradict the historical sources that the
painter did not resort to the preliminary graphic phase: the infrared multispectral scanner
revealed, in addition to the presence of the typical engravings, the graphic contours of
the hands, the face of Christ and the apostles. Through the infrared reflectography, in many of
the artist’s works, in some cases drawing traces are visible to the naked eye. Such as the margins
of the Giuditta of the National Gallery of ancient Art in Rome, where it is easy to distinguish
the subtle dark strokes of the outline. On the graphic of the shady ground, not
yet dry, Caravaggio began to paint with quick and loose brush strokes but
at the same time strong and full. The preliminary drawing thus
came to be one with the sketch. According to the testimony of Pietro Bellori:
Caravaggio “left the priming of the canvas in half shades”, that is, he used the brown color of
the preparation as a half tone for the dimness. The lead white in the light
areas of the complexion is applied in increasingly lighter tones, up
to the final touches made with pure white. In radiographs, a spiral pattern of
white brush strokes is often observed. If the contemporary painters of Caravaggio
made a body sketch on which they then spread glazes to finish it, Caravaggio revolutionized
the techniques by completing his paintings, part by part, in a single session. The glazes are spread without allowing
the underlying color to dry completely, so that the two pictorial
surfaces are mixed together. Already at the sketch level, painting appears
so defined and studied in every detail. That is, the painting is built with the paste of
color and not by layers, thus the body- kneading technique was born, which then remained
typical of many areas of the Mediterranean. The full-bodied workmanship of the sketches
whose brush stroked rich in pictorial mix, fast, moving and not always
corresponding to the final draft, as well as the speed of execution depended on
the habit and willingness to copy from the model. PIGMENTS The coloring materials used by
Caravaggio are relatively few; his palette is based on lead white, yellow and
red ocher, cinnabar, copper green, charcoal black, earth. The use of bright and decisive colors found
in his youthful works seems to diminish in the painting of late maturity, in which dark and muted
shades predominate and earth-based colors appear. Still Bellori informs us that the painter
“used a more dyed color…all effected by vigorous shadows using much
black to emphasize the bodies”. UNCOVERED STRIP Typical of the artists the
process of leaving exposed, around the complexions, an uncovered strip of
preparation that reveals its reddish-brown color. This can be explained by the very rapid execution, that is, to proceed quickly, without
waiting for the contiguous area to be dry. This procedure is certainly linked to the practice
of painting from natural with the model in front. The rapid final draft went just beyond
the sketch or even identified with it, so much that egg tempera highlights were
superimposed on the still fresh oil layers. The egg tempera (found in some of the artist’s
work) allows to intervene on the still fresh color without melting the layers, this seems to confirm
that more often Caravaggio did not put his hand back to the painted part and all this
appears in line with the use of the model. The artist’s finishing work was
limited to small touches such as revising the features of the faces with black. The energy and the decision of the artist’s
brush strokes were reconciled with and extraordinary attention to the smallest
details, painted with a small brush. Caravaggio did not cut his figures
within well-defined profiles but he did them in full starting from the bottom
and then superimposing those in the foreground. Figures, clothes and objects are
built in succession of often overlap, like the foreheads of the faces covered by
hair or the arms outlined in full and later, covered by the cloaks or sleeves of the clothes. “Scientific reproduction” makes use of:
- All available information obtained by the study of sources, treaties, testimonies, ancient cookbooks
- Information extracted from restoration reports, often accompanied by diagnostic tests aimed
at understanding the execution technique and finally - The information obtained from
the careful observation of the works preserved, in particular those left unfinished by the painter but also those on which interventions of
careless restoration occurred in the past, have highlighted layers of material
originally hidden from view. It is not possible for me to show the results
of the comparison between the scientific reproductions shown here with the radiographic or
cross section investigations of the original work as, at present , the rights of the latter do not
allow it but, on one of the reproductions , a very aggressive cleaning operation was carried out
in order to verify whether the progressive unveiling of the layers would
have resulted in bringing our reproduction to a similar appearance to the
original which, as in the case of the painting depicting Sant’ Orsola, by sure hand of Caravaggio
has, in the past undergone a similar treatment. If not a verification of the
correctness of the methods followed during the scientific
reproductions of the work, this procedure could shed light on some aspects
still discussed of the artist’s way of proceeding.
