the Society for the Preservation of New England Antiquities (SPNEA) became involved with historic paint and color analysis, at the Harrison Gray Otis House in Boston. At the same time, E. Blaine Cliver, historical architect, who had worked with Batcheler at the National Park Service in Philadelphia, with the National Trust for Historic Preservation in Washington, DC, and later at the Northeast Regional Office of the Park Service, became involved with historic paint analysis. He set up a laboratory in Building 28 of the former Boston Navy Yard. In the early 1970s, Frank S. Welsh joined the National Institute of Standards and Technology in Philadelphia and began to study historic paints with Batcheler. Welsh introduced the use of the National Bureau of Standards Color Name Charts, (National Institute of Standards and Technology) for naming colours matched to the Munsell color system. Welsh introduced the term "paint analysis" into the lexicon of historic preservation. There currently exist a variety of private firms performing scientific paint analysis. Some notable firms include Lincoln Conservation in the United Kingdom and David Arbogast. Smaller companies such as John Canning: Perfecting Finish also specialize in historic paint analysis and most have websites detailing their services and publications. Sampling methods Historically, paint analysis was done on-site by carefully removing later paint layers to reveal a sequence of finishes down to the substrate, this method is commonly referred to as the scratch and match method. This was the methodology employed during the early restoration of finishes at Historic Williamsburg. Although this method is employed by a few practitioners, it is not common because of its inherent problems of misinterpretation and failure to address issues such as paint aging and discoloration. Because finished analysis is performed under laboratory conditions samples are collected in the field for later analysis and can be collected by the analyst or by ship to a client. The samples are labeled during the collection process. Typical information includes the sample number, building name, building location, name of the collector, date of collection, and specific data regarding the actual location of the sample. According to David Arbogast's sample collection, samples are typically collected in one of two types of packages. Manila coin envelopes are highly recommended. They have large flaps which should remain unsealed. There is virtually no possibility of the sample migrating from such an envelope. The other possibility is plastic resealable (Ziploc) bags which