Art conservation and architectural history

During the decades that their prominent architectural firm Collins & Autenrieth flourished in 19th-century Philadelphia, German-born partners Edward Collins (1821-1902) and James M. Autenrieth (1828-1906) designed both public and private buildings. Some have endured, but many others have been altered significantly or demolished, making the hundreds of architectural drawings, blueprints, and notebooks now archived in Special Collections at the University of Delaware among the only records of the firm’s work and its role in the history of Philadelphia architecture.

One example, an architectural drawing dated January, 1878, was part of the firm’s design plans for the Romanesque-style Central Presbyterian Church in Philadelphia. This year the drawing became both a technical study and treatment project for Winterthur/ University of Delaware Program in Art Conservation (WUDPAC) Fellow Emilie Duncan, a library and archives conservation major. Emilie looked forward to both studying and treating the drawing, and to learning more about the little-studied architects and how they worked.

The church building, located on north Broad Street in Philadelphia, is home now to a Baptist congregation. The original appearance of the interior, thought to have undergone many changes, is suggested by the details included in the drawing. Done on a high-quality, wove paper, the drawing shows one-quarter of the building’s domed ceiling, including the supporting corner pendentive and arched colonnade. Emilie believes the drawing’s varied design motifs and many colors, done in translucent watercolor washes and opaque body colors, indicate that the artist was experimenting to see which colors and patterns he liked best.

Emilie’s primary concern was the many blackened areas that affected the drawing’s aesthetic appearance. Through analysis, she determined they were due to lead white pigment that likely had been added to the watercolor wash as an opacifier, but which is also known to form lead sulfide and turn black when exposed to the sulfur commonly found in the atmosphere. Emilie has used erasers, brushes, cosmetic sponges, and other dry cleaning agents to remove dirt and grime from both sides of the drawing. Future treatment may include applying an oxidizing agent to whiten and lighten the darkened spots and mending a number of small tears by applying Japanese tissue paper to the reverse side with wheat starch paste. Once the work is complete, the drawing will be returned to Special Collections at the University of Delaware, where Emilie’s research will help contextualize the drawing within both the other works held there and the larger scope of Philadelphia’s architectural history.

A printable PDF version of this story is available here.

(Photos: Melissa Tedone, Emilie Duncan.)