Paper Conservation: Decisions & Compromises

Color Printing in 16-17 th -Century Italian Chiaroscuro Woodcuts:
Degradation, Conservation Issues and Exhibition Concerns
Linda Stiber Morenus
Library of Congress, Washington, DC, USA / Staatliche Akademie der Bildenden Künste Stuttgart, Germany
or dark colored ink. The printmaking process
results in an image of complex stratigraphy.
Together, the layered ink colors were usually
chosen by the printmaker to create a sense of
volume or spatial recession - prime objectives of
Renaissance imagery. The rich visual language
of the chiaroscuro technique is predicated on
the varied and nuanced colored inks and printing
effects which give the medium its expressive
power. There is a vast literature dedicated to the
composition and behavior of printing ink over
the centuries, however no study addresses systematically
oil-based colored inks as used in 16 th -
17 th century Italian chiaroscuro woodcuts.
Christ Healing the Paralytic BXII.38.14 by Niccolo
Vicentino Library of Congress FP-XVI-V633, no.2
Italian chiaroscuro woodcuts are among the
most innovative of Renaissance prints. A woodcut
print is made from a wooden plank that is
carved in relief, inked, and impressed in paper.
Chiaroscuro woodcut prints – named from the
Italian term for contrasting light and dark tones
– emulate drawings of the period. The design of
a chiaroscuro woodcut is distributed over two
to five woodblocks that are printed in superimposed
layers of colored inks, thus creating transitional
passages of shading. These tonal passages
are often anchored by a “key” block which carries
the primary outlines of the design in black
Many centuries after a chiaroscuro woodcut was
originally executed, deterioration can affect its
legibility, and distort the historical and aesthetic
interpretation of the work. Moreover, a correct
assessment of condition is fundamental to selecting
appropriate conservation and preservation
measures.
Colored printing ink can become altered by
a number of degradation phenomena. Understanding
the durability of vehicles and colorants
is central to an accurate reading of chiaroscuro
prints. Vehicles for early modern period inks are
typically composed of drying oils, with possible
admixtures of natural resins. Both share a tendency
to become brittle and yellowed with age.
Darkness and humidity increase this tendency
(Gettens and Stout 1966: 46). Some inks of the period
are subject to colorant deterioration. In his
valuable study, A History of Printing Ink, Balls
and Rollers 1440-1850, Colin Bloy distinguishes
the light stable pigments – inorganics, earths,
and metallic compounds – from the fugitive organic
colorants, including indigo and lakes (Bloy
1972: 40). Other pigments are chemically reactive,
such as copper acetate, lead carbonate and
lead oxide. Breakdown of colored ink also can
lead to blanching – a clouding effect. Finally, the
paper support may undergo ink-associated damage
as well.
ICOM-CC Graphic Documents Working Group Interim Meeting | Vienna 17 – 19 April 2013
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