The New York State Library recently awarded a grant to the Municipal Archives Conservation Unit to perform much needed treatments on large-scale drawings and plans for Central Park and the Brooklyn Bridge.

These two icons of New York are among the most important public works achievements in the city’s history. Beyond the technological and design innovations, the bridge and park have become symbols of the city itself. The more than 200 drawings that are the subject of the grant exhibit the remarkable level of detail and artistry that went into the planning and construction of each structure.

The project focuses on the largest items in each collection, some of which are 34 feet long! Conservation staff are undertaking a variety of activities to assess and stabilize these delicate materials.  These include mending and lining fragile drawings, stabilizing media, washing to remove harmful degradation products, reducing stains from mold and other sources on some of the most important drawings, as well as creating new housings for long-term storage.

The grant funding also supported the purchase of a Zeiss stereo microscope with a digital camera, and portable UV lights. This equipment allows conservation staff to analyze drawing media and supports, assess mold and other types of damage, and take high quality images of fine details, all of which will inform the treatment methods chosen. Additionally, the lab was able to purchase a large mono-stand for photographing oversized collections, both for documentation of the treatments performed as well as to provide another source of research access to these large, unwieldy objects.

The Brooklyn Bridge and Central Park plans comprise some of the most treasured collections at the Archives. Dating from 1850 to 1934, the Central Park plans provide complete documentation during the critical stage of the park’s design and construction from 1850 to 1880. The collection includes renderings of everything from landmark structures like the Boathouse, Belvedere Castle, and Sheepfold to a three-level circulation pattern for people, horses, and vehicles.  The oversized drawings included in the grant project detail the design of the Metropolitan Museum of Art and the Museum of Natural History, gates and entrances to the park, paths and walkways, drainage systems, and other elaborate details.

The Brooklyn Bridge collection documents the original construction and subsequent alterations of the 1,596-foot steel suspension bridge connecting Manhattan to Brooklyn. At the time of its completion in 1883, the bridge was the longest in the world and was an important technological achievement. The total 8,706 drawings in the Bridge collection span from 1867 to 1938.  They were produced by architects and engineers who developed techniques for bridge construction that were unknown or considered unproven among their profession at that time. Many of the drawings in the collection are the work of the most celebrated American engineers and architects of the nineteenth century, such as John and Washington Roebling, George McNulty, and Wilhelm Hildebrand. The largest of these drawings is over 34 feet in length.

The drawings and plans in both the Central Park and Brooklyn Bridge collections have similar characteristics. They represent a variety of media (watercolor, graphite, inks, crayon, and photo-reproductive processes) and supports (tracing paper, watercolor paper, cloth-lined paper, and tracing cloth).  Unfortunately, improper storage and handling over the decades prior to acquisition by the Archives has led to physical damage to varying degrees in the form of acidic and deteriorated supports, flaking media, iron gall ink damage, and tears and fractures.

One of the greatest challenges of treating these materials is simply moving them back and forth from and within the lab. Conservators Sara Bone, Clare Manias, and I have developed a workflow for carefully shifting and transporting the drawings using light, but sturdy, foam board to support their weight. We have also refined methods for photographing, cleaning, and performing various treatments on a much larger scale than we are generally accustomed to. Planning each move in advance, and of course teamwork, are key to safely maneuvering these massive and very delicate drawings.

The ultimate goal, as with most of the work we do in Conservation, is to make the oversized drawings safer to handle, more accessible to researchers and well-preserved for the future. As the project moves forward in the coming months, we will continue to learn a great deal about the collections and further refine our treatment methods. Given the many thousands of oversized maps and drawings in the Archives’ collections, these skills will no doubt be put to use again once this project is completed. Although challenging, the work will ensure the viability of these iconic materials for many generations to come.