Historical Painting Techniques, Materials, and Studio Practice

paint, that the paint remains drained [prosciugato], so that it can no
longer be seen evenly on the suiface, as would have been the case when
such an accident would have been prevented. By means oj another unctuous
substance, which is the varnish, applied to those areas where the oil is
missing on the suiface (and this is the crux of the matter), the dark colors
are made to reappear. These are the dark pigments which are really present
in the oil painting, not those darks that just appear dark but are not
physically present, as was in fa ct the iff ect created by Apelles's varnish in
some very small areas on his paintings.
Many of Baldinucci's points require and deserve investigation; I will confine
myself to examining his assertion that varnish in his time was applied as a
retouching remedy locally rather than over the whole work (as the oil medium
itself provided the saturation required to "bring the whole closer to
natural appearances"). I shall also fo llow up his point linking this localized
"sinking-in" with absorbency of the ground layer.
We are indebted to the Englishman Richard Symonds, an amateur painter
who spent 1646-1647 in Rome, fo r the very detailed and painstaking notes
he took while watching Gian Angelo Canini painting in his studio. Canini
was a fr iend of Poussin's, and like the latter, trained in Domenichino's studio
in Rome.
Symonds describes on several occasions that portions of Canini's paintings
were "sinking in" (prosciugated), and he also described the remedies that
Canini applied. Giving an account of the painting of a portrait of Sir Thomas
Killigrew, he describes how: "the face and field were prosciugated ... nitwithstanding
oyle was putt upon the back side of the cloth." This he blamed
on the fact that the "cloth" (and he marked "imprimatura" in the margin)
"was not as perfectly dry as it ought. I askt him how he would fetch the
colour of the face, he sayd he would give it a semplice chiara d'uovo [eggwhite]
beaten together . .. or olio di sasso, another varnish" (10).
Elsewhere, Symonds describes Robert Spenser's portrait, painted in one sitting
by Canini (1 1):
The scaife which was crimson he did with lacca / biacca Qake and lead
white]. The whole scaife being done, and afo re it was dry he putt on gold
colour for the fringe, all which kept his fresh colour and needed no varnish.
Not three days after, when one would thinke it was scarce dry he with a
pencill of setola [hog] putt on his varnish over the first field & face &
Armour & hands, but not the scaife or benda, / this kind of varnish he
esteemed above that of Olio di Sasso.
For the preferred varnish, he gives the following recipe on f.20: "2 oz. of
seven times distilled aquavita (spirits of wine) 112 oz. of ground sandarac
112 oz. of olio d'Abezzo [Strasbourg Turpentine]." This "final" varnish was
only applied to those areas which he felt required it. He was also quite clear
that certain pigments should not be varnished.
Symonds questioned Canini about the sky in a monumental painting that he
executed on the subject of Anthony and Cleopatra: "2 days after the Azzurro
ayre was dry, and I askt him what if it should prosciugare [sink in], so much
the better said he, because you never put vernish over azzurro" (12).
The reason for this answer may be in the yellowing characteristics of the
varnish or in a deliberate choice fo r the matte quality of the blue with a
consequent increase in scattered reflection, and of the white component in
light. This effect, to be avoided in darks, but desirable for achieving the effects
of aerial perspective, was advised by Leonardo in his treatise on painting. One
should not forget that all the artists in Poussin's circle had a strong interest in
optical matters, and studied mathematics and optics with the best mathematicians;
in addition, Galileo moved in this same circle.
Canini was also aware that certain pigments, such as blacks, caused problems
by drying matte: "Black, even varnished, sinks in," meaning that unless cor-
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Historical Painting Techniques, Materials, and Studio Practice