The Staircase - an introduction

After completing the frescoes in the Imperial Hall in July 1752 Giovanni Battista Tiepolo and his assistants began preparing the plaster and painting the large trough vault in the staircase of the Würzburg Residence.  First the huge surface (677 square meters) had to be covered with a second layer of plaster because the vault, built of brick and calc tufa, had already been plastered with an initial layer of limestone mortar after the rough construction was completed in 1743.  After the two-layered ground (arriccio) had dried, lines and probably also grids or even sketchy contours of the carefully prepared individual depictions could be drawn.

Working from the top to the bottom, the finer ground (intonaco) was applied and painted over the course of each day’s work (218 giornate).  The painting combines the techniques of fresco and secco painting (see “Painting Technique”), as was common for such commissions in the mid 18th century.

Heaven and earth are depicted in a sort of macrocosm.  In a complex allegorical representation the continents of Africa, Asia and America are paying homage to Europe and to the picture visible above them, and thus to the Würzburg prince-bishop Carl Philipp von Greiffenclau, who commissioned Tiepolo.  The artists involved in construction of the Residence, including Balthasar Neumann, Antonio Bossi and Tiepolo and his son, are portrayed in the group of figures on the side depicting Europe.  Above the earth, or the four continents, is a heavenly vault with Apollo as the central figure, surrounded by the ancient gods.

Balthasar Neumann, the architect of the Residence and designer of the staircase, is portrayed on the side of the fresco depicting Europe.

The Damages

The scientific analyses undertaken showed a high degree of gypsum formed on parts of the paint layer as well as a concentration near the surface of magnesium sulfates of different hydrate stages.  The lower portions of the painting (the depictions of the continents) are particularly affected.  But there is also considerable salt efflorescence on the depiction of the heavens, as a result of water penetration (leaking roof).

Salt efflorescence on the side of the staircase fresco depicting Asia

Salt efflorescence on the side of the staircase fresco depicting Africa

Powdering and flaking paint layers in the secco parts can be traced in part to the disintegration of the binder (microbiological substances and possibly their waste products).  Previous consolidation efforts applied binding agents which sometimes left a glossy film on the paint layer or caused detachment of patches because of high inherent stress (casein, for example).

"Philosopher” on the side of the staircase fresco depicting Europe, loss of paint layer through salt activity

Flaking paint layer on Asia’s face in the staircase fresco

Flaking and blistering detachment of secco paint layers on the staircase fresco

Small-scale cleaning efforts before 1944 (see “History of the Restoration”) removed or effaced the uppermost pigment layers.  Microbiological attacks in the form of small round mycelium structures are present in numerous places.  Cavities and cracks in the plaster support are found above all on the groins of the vault, i.e., over the corners of the staircase. There are also numerous mechanical damages resulting from careless erection of scaffolds, scratches resulting from pigeon landings, bullet holes, etc.

All of the damage phenomena were mapped and as far as possible documented with photographs.  The individual phases can be laid over one another as digital transparencies so that the increase or reduction of damages can be depicted and the interdependence of the phenomena can be perceived and analyzed.