Saint Catherine of Alexandria and Saint John the Baptist

Giusto de’Menabuoi
Late 14th Century c. 1363

tempera on wood panel

56.8 x 30.5 x 3 cm

The Georgia Museum of Art, University of Georgia, Athens, GA

Saint Catherine of Alexandria and Saint John the Baptist are two panel paintings by the Northern Italian artist, Giusto de’ Menaboui. Although they present un-balanced conditions, these two gold-ground panel paintings are currently displayed together in the Georgia Museum of Art, Kress Collection. The goal of my treatment was to investigate their individual condition issues and improve their aesthetic balance when seen together. This treatment was performed in 2016 under the supervision of Dianne Dwyer Modestini, as part of the Kress Program in Paintings Conservation at the Institute of Fine Arts, NYU.

Before treatment image. 

The panels were removed from a large altarpiece by and have been matched to a central Madonna in Museo Nazionale di Palazzo Reale in Pisa, Italy. During or after their removal, the panels were thinned and cut to a new rounded arch shape. Vestiges of their previous engaged frame were noted in the bands of punchwork outlining a slender inverted triangle. Previous restoration in these areas obscured the original shape of the panels and covered original gilding which remained in the recessed punchwork. It was decided that these should be removed to reveal the shape of the previous engaged frame, and facilitate understanding of the original altarpiece construction. A gel of Klucel G and dimethylsulfoxide (DMS) in ethyl acetate, was used to remove overpainted restorations without disrupting the water gilding below. Working under a microscope, the fill materials were then mechanically removed to reveal original gilding and gesso layers.  

Current reconstruction of the altarpiece by Hae Min Park, NYU graduate.

Outline of framed shape by HaeMin Park on related panel, Saints Paul and Augustine in the Kress Collection.

Saint Catherine during treatment, 10X magnification.

Punches outlining the pendentive, Saint Catherine Left: before treatment Right: after treatment

Punches outlining the pendentive, Saint John Left: before treatment Right: after treatment

Microscope cleaning of oxalate coating.

Removal of oxalates Left: before treatment Right: after treatment

Abraded gilding before treatment.

Laying new gold leaf.

Gilded background after treatment

Abraded condition of Saint John the Baptist

After treatment Saint John the Baptist

Before treatment

During varnish removal

Cleaned state

After treatment

Patchy deposits of a dark gray crust were observed across both gilded and painted surfaces of the panels. Previous analysis of similar deposits on a panel from the same altarpiece in the Kress Collection, had characterized these as an oxalate crust. The dark areas of thick oxalates across the modeled highlights of Saint Catherine were visually distracting. After testing, oxalates were removed over the highlights of the painted surface by softening with the same cleaning gel and removing them mechanically under the microscope.

Due to the advanced abrasion of the Saint John panel, oxalate deposits were small and less disruptive. However, large losses in the gilded background detracted from its appearance. To bring this panel into line with its original appearance, these losses were re-gilded. Gamblin pigmented wax resin was thinned with xylene and painted over areas of loss. Clear wax was buffed over the pigmented wax,warmed with moist breath, and then covered with gold leaf. The gold was then distressed, abraded, and toned to mimic the original surface.

For further details of this treatment download the report below.