Marcinkowski, Wojciech [Editor]; Zaucha, Tomasz [Editor]; Museum Narodowe w Krakowie [Editor]: Plaster casts of the works of art: history of collections, conservation, exhibition practice ; materials from the conference in the National Museum in Krakow, May 25, 2010 (Krakau, 2010)

Anna Kłosowska, Michał Obarzanowski • Plaster casts in the collection .

Plaster is a fragile material, so on most occasions inner constructions are introduced
during the casting process. Depending on size, shape and form, a range of materials
can be used. Steel rods for limbs or other protruding elements, wooden frameworks
for exterior supporting constructions, meshes made of metal, textile or tow for thin
layered surfaces.

These reinforcements improve the object s durability and stability but, on the other
hand, they react differently than plaster to environmental conditions, which may
play a major role in the object s destruction (fig. 6).

Corroded inner metal structures were observed in damaged areas. Corrosion prod-
ucts penetrating the porous structure of plaster became visible as extensive stains
on the surface (fig. 7). Swelling of the rusted material caused cracking of the plaster.
Deformation and damage of wooden supports caused further destruction due to
alternating swelling and shrinking of the wood in changing rh (relative humidity)
and temperature conditions (fig. 8).

Fig. 4. Cathedral
of the Assumption
of the Virgin Mary
in Gniezno. Panel
of the Gniezno door.
Scene iv. St Adalbert
prays in front
of the temple.
Inv. no. mnk l-g-258/3.
State of preservation
during conservation.
Object heavily cracked.
Photo by Michał
Obarzanowski

II

ffiVS

Pig. 5. Tomb of king

WSBWiiMSSk ■ \y^l.,f Ladislaus Jagiełło,

panel in baldachin
soflitto.

Triton (nw corner).

,„ \ «I:. - . Inv. no. mnk 1-g-101.

■Pit' 1

State of preservation
before and after

Y, y;;;^yyäM^m:::

conservation.
Photo by Michał
Ä? Obarzanowski

105