35
These and other sources and types of damage have long plagued
curators and owners of these delicate frescoes. Many early attempts
to conserve artworks ultimately did more damage than good. At
one time, for example, varnishes were used over paintings in a
misguided attempt to protect them. These now-darkened varnishes
are a major problem in restoration efforts today. In more recent
years, less problematic acrylic polymers such as ethyl methacrylate
(paraloid) as well as others have been used to consolidate wall
paintings. Even the best of current techniques, however, can still
result in some type of change, not be very effective, or simply be
short lived.
Methods of conservation have come a long way since the use of
varnishes, but the many inherent challenges have not been entirely
overcome and the process remains painstaking. Current restoration
and conservation standards demand that any conservation or restoration technique be reversible and should in no way alter the
fundamental chemical or physical composition of the original artifact or otherwise affect its properties. New techniques were developed as a consequence of the terrible floods in Florence and Venice
in 1966 that caused widespread damage to the art and architecture
of these cities. One important method developed shortly thereafter,
the barium or Ferroni-Dini technique, used chemical methods
for consolidation and restoration of wall paintings suffering from
salt crystallization. The method seeks to reconstitute the calcium
carbonate layer. Surface applications of aluminum and barium
hydroxides are applied so that harmful calcium sulfates are ultimately converted into inert barium sulfates. These, in turn, ultimately act to consolidate the substrate and to create a fresh binder.
This technique has been widely used throughout the world and
has led to the development of other sophisticated techniques as
well.
Researchers at the Center for Colloid and Interface Science (CSGI)
at the University of Florence have extended the Ferroni-Dini method
using nanomaterial technologies. Calcium hydroxide would be
especially desirable for conservation use with carbonate-based
materials because of compatibility. A saturated calcium hydroxide
water solution, known as lime water, has been used, but its low
solubility has presented problems. The use of calcium hydroxide
suspensions has been explored, but these are not stable enough
and create surface effects. Researchers at the Center explored the
use of dispersions of nanosized calcium hydroxide in nonaqueous
solvents. Nanoparticles of this type can be obtained from a simple
homogeneous phase reaction in hot water. Going to smaller sizes
Nanomaterials in Art and Cultural Heritage
These and other sources and types of damage have long plagued
curators and owners of these delicate frescoes. Many early attempts
to conserve artworks ultimately did more damage than good. At
one time, for example, varnishes were used over paintings in a
misguided attempt to protect them. These now-darkened varnishes
are a major problem in restoration efforts today. In more recent
years, less problematic acrylic polymers such as ethyl methacrylate
(paraloid) as well as others have been used to consolidate wall
paintings. Even the best of current techniques, however, can still
result in some type of change, not be very effective, or simply be
short lived.
Methods of conservation have come a long way since the use of
varnishes, but the many inherent challenges have not been entirely
overcome and the process remains painstaking. Current restoration
and conservation standards demand that any conservation or restoration technique be reversible and should in no way alter the
fundamental chemical or physical composition of the original artifact or otherwise affect its properties. New techniques were developed as a consequence of the terrible floods in Florence and Venice
in 1966 that caused widespread damage to the art and architecture
of these cities. One important method developed shortly thereafter,
the barium or Ferroni-Dini technique, used chemical methods
for consolidation and restoration of wall paintings suffering from
salt crystallization. The method seeks to reconstitute the calcium
carbonate layer. Surface applications of aluminum and barium
hydroxides are applied so that harmful calcium sulfates are ultimately converted into inert barium sulfates. These, in turn, ultimately act to consolidate the substrate and to create a fresh binder.
This technique has been widely used throughout the world and
has led to the development of other sophisticated techniques as
well.
Researchers at the Center for Colloid and Interface Science (CSGI)
at the University of Florence have extended the Ferroni-Dini method
using nanomaterial technologies. Calcium hydroxide would be
especially desirable for conservation use with carbonate-based
materials because of compatibility. A saturated calcium hydroxide
water solution, known as lime water, has been used, but its low
solubility has presented problems. The use of calcium hydroxide
suspensions has been explored, but these are not stable enough
and create surface effects. Researchers at the Center explored the
use of dispersions of nanosized calcium hydroxide in nonaqueous
solvents. Nanoparticles of this type can be obtained from a simple
homogeneous phase reaction in hot water. Going to smaller sizes
Nanomaterials in Art and Cultural Heritage