An Innovative Technique for Reforming Cellulose Acetate in an Architectural Model of Rockefeller Plaza and the Challenges of Preserving Modern, Unstable Restorations

Christina Krumrine


A large, detailed wood and plastic architectural model of Rockefeller Center, made shortly after the construction of architect Raymond Hood’s iconic complex in 1931, was displayed at Rockefeller Center in NYC for decades. In 1998, the model was donated to a prominent museum. In 2008, the museum had the model conserved and loaned it (with the exception of the Radio City Musical Hall building) back to its original owner. For the next 10 years the model was displayed at the 30 Rock Visitor’s Center in an unsealed case. Fluctuations in temperature and relative humidity in the Visitor’s Center and excessive UV light exposure caused the plastic windows and walls of the structures to shrink, warp and pull away from the model’s wooden framework and the wood veneer laminate on the plastic walls to buckle. When a security guard questioned the deteriorated state of model, the museum checked the objects condition for the first time in a decade. Christina Krumrine was asked to stabilize the model’s structures and return them to their original appearance. Out of an abundance of caution, the conservator sent samples of the plastic for analysis to make sure it as not cellulose nitrate, which was in wide use in the 1930s and is extremely flammable. FTIR analysis identified the samples as cellulose acetate with residual plasticizers. After consulting with plastics conservator Yvonne Shashoua, and inspired by a presentation at the 2017 Gels in Conservation Conference in London, the conservator decided to borrow a technique introduced in 2010 at the AIC Painting Conservation Specialty Group that utilized thermal blankets to reduce distortions in easel paintings. While there was no conservation literature on the use of heat and weights to reform plastics found in museum collections, the use of mild, controlled heat seemed not only rational and innovative, it seemed like the only possible solution. And, in the end, was very effective. After the conservation proposal was accepted by the client, the conservator was granted access to the Rockefeller Archives. The archivist, who had previously been a restorer, explained that she had led a major restoration of the model in 1982. While she was unable to find any reports or recall any of the materials or techniques used in that restoration, she did provide detailed color transparencies documenting her alteration and, in many instances, replacement of the model maker’s original materials. What was once thought to be an important model from the studio of a renowned architect turned out to be an attractive pastiche that fooled conservators, curators and architectural historians alike. The Rockefeller Center model proved to be quite a conservation challenge. The new approach to reforming warped plastic turned out to be the easy part. Determining how to preserve the well-crafted object’s integrity despite a heavy restoration that replaced original material with unstable materials utilizing questionable techniques posed difficult questions for the conservator.

2019 | Uncasville | Volume 26