| Choice
of Treatment
Treatment
on this object was performed in two phases:
Phase
I: Neutralization of Substance Used for Cleaning
Results
received from Laboratory for Research of Materials indicated
on presence of soda (NaOH) in booth samples. To remove
it in order to prevent from very possible reaction with
materials that will be in use in restoration process,
object was rinsed with 50% ethil alcohol followed by
rinsing with nitro thinner (7).
Phase
II: Choice of Restoration Treatments
Selection
of the Materials and Procedures for Crack Recovering
For recovery
of cracks in wooden body test was made with admixture
of powdered gypsum (CaSo4), Kaolin and PVAC resin. Prior
to application of admixture crack was moistened with
15% ethyl alcohol to assure good contact of admixture
and wood. Solidification time was about 15 minutes.
Sample was left to dray for 12 hours. Test resulted
with solid, consolidation backfill.
Selection
of the Materials and Procedures for Consolidation and
Recovering of Original Gesso
Due to good
experience with admixture tested on cracks, it was tested
for filling of areas of ornament where the parts of
original gesso missed. Area was prepared with 15% ethyl
alcohol as the crack in previous test. Admixture was
pushed into and flattened with moistened spatula. The
Result was satisfactory.
In order to consolidate the small cracks in original
gesso, make better contact within original gesso and
new fill and make solid ground for new gesso the 'contact
ground' was tested. Request was to obtain surface solid
enough to resist pressure during the polishing of gold
and silver and porous to except new gesso. The ground
was composed of calcium carbonate, in form of fine powder
(Bologna chock), zinc oxide powder and PVAC resin. By
the and of mixing 90% Izo propil alcohol was added to
improve leaving of captured air. To make it applicable
with brush admixture was diluted with distilled water.
Surface was coated 3 times with time delay of 15 minutes
to provide solidification time for each layer. Sample
was left to dray for 12 hours. The result was solid
but porous surface, resistant enough on pressure preventing
the original gesso from delaminating.
Selection
of the Pigments and Ground for Pigment
Pigment
test result helped in determination of color and adoption
of hue. Due to previous good experience with Oil type
(1) pigment, It was decided, to use it in this occasion
too. Pigment was mixed with prefabricated oil color
medium (2) offered by same manufacturer.
To make a ground for mixed oil color it was thought
that it would be much better to use prefabricated ground
for oil colors applicable on wood instead of any kind
of gesso made of calcium carbonate, filer and organic
or inorganic resin. Test was made with prefabricated
UB ground (3) applied in two layers. Property of this
ground is to seal pores of wood with very thin layer
on it. Test result was very good. Oil color distributed
successfully and did not penetrate, after drying layer
was even in shine and hue.
After analyzing quite similar objects made in same period
(middle of 19th century) and in same stile (neo Rococo)
it was decided to make light France polish on colored
segment in order to achieve shine, deep look. Test was
made with bleached shellac (4) to avoid deformation
of color hue and result was good.
Selection
of the Type and Hue of Gold Leafs and Material for Imitation
of Gilding
In order
to achieve deeper, sad look of water gilded ornaments
24 karat 3 layer gold leafs were selected. To contribute
to this look, dark red bole was selected. For finishing
background of floral ornaments in the middle of object
schlag metal was selected, with corresponding hue to
hue of gold leafs.
To emphasize engraved floral ornament in the middle
of object and net looking ornament in the middle of
appears part of object, but to make corresponding hue
with surrounding green color Mica powder mixed with
small amount of green neutral pigment (5) was selected.
Restoration
Process
Tested admixture
was applied on cracks and flattened by moistened spatula.
Prior to application cracks was moistened with 15% solution
of etil alcohol. Delaminated peaces of ornaments gesso
were removed mechanically. Previously tested Procedure
was applied now. After 12 ours of drying areas of intervention
were shaped by the help of turbine.
Prior to application of the 'contact ground' surface
of ornaments was cleaned whit 96% ethyl alcohol. The
'contact ground' was applied in three layers as it was
tested and then left to dray for 2 hours. New traditional
gesso made of technical whiting (CaCo3), zinc whiting
(ZnO2) and rabbit skin glue was applied shortly afterwards
in four layers. Every layer was left to solidificate
for 15 minutes.
After 12 ours surfaces of ornaments was shaped with
sandpaper. In order to prepare flat and smooth surface
important for quality of water gilding sanded surface
was colored with ocher bole and sanded again with 4
grades of sandpaper. During the sending surface was
rinsed with mineral spirit. Next 12 ours object was
left to dray (fig.3.).
|
