by Donna Baron
- May 21, 2005 – the Dendrochronologists arrive
- June 8, 2005 – Paint Analysis Continues
- July 11, 2005 – The scaffolding arrives!
- July 14, 2005 – Documentary photography begins
- September 2-13, 2005 – The endoscope – how cool is that!
Dendrochronology is the science of tree rings. During every year of a tree’s life, it deposits a new outer layer of cambium, the green material just under the bark. Depending on the climatic conditions during a particular growing season, that layer may be narrow or wide. Over time, the tree’s trunk develops a pattern of concentric rings that, when viewed in cross-section, reveal how old the tree is (one ring for every year) and what the growing conditions were like over its lifetime. Trees of the same species growing in geographic proximity to each other tend to develop very similar growth patterns. Scientists who study tree rings (dendrochronologists) build databases of cross-sections to allow comparison over time. Starting in the 1970s, historic preservationists have also used dendrochronological samples to date timbers from old buildings. Because the Webb House’s construction date is well established (at least for the framing of the main block) through archival research, the Webb-Deane-Stevens Museum offered to allow samples to be taken of the house’s framing members in order to contribute information to the New England-area dendrochronology database. We also hope to determine the relative age of different areas of the house, including the ell.
The photo shows dendrochronologists taking samples from various framing timbers in the Webb House. These samples will be flown to the United Kingdon for analysis, with results expected by the end of 2005.
Paint analysis is the process of studying the layers of paint on a particular surface, which generally build up over the life of the object. The various layers of paint colors collectively form the “paint history” of the surface or object. This paint history tells us something about how people have viewed and used the surface over time. The top, or exposed, layer of paint is the newest, and those underneath are progressively older. If a layer shows a lot of dirt, wear, and degredation, we know that that particular layer was on top for a long time. Similarly, if a particular layer doesn’t show much wear, we know that it was only exposed for a short while before being covered with a different paint. Colors also change over time, both due to fashion and to chemical changes in the paint material itself.
An architectural historian will come in to a house like the Webb House and take samples of painted surfaces in order to determine how old that surface is, whether it has the same paint history as an adjacent surface (if not, we know that changes occurred to the room at some point in the past), and what the surface might have looked like at different times in its history. A house as old as the Webb House will have a long and complicated paint history, and paint analysis can yield very important information about how and when changes both large and small were made.
The photo above shows Brian Powell examining woodwork in Webb House through a powerful portable binocular microscope. Having examined an area in this manner, he will then take a sample that will be studied further in the laboratory. His final results will include a mathematical formula indicating the original color of each layer of paint in that sample, called a Munsell number.
In December 2001, the Webb-Deane-Stevens Museum commissioned Brian Powell of Building Conservation Associates to conduct paint analysis of the Revolutionary-era exhibit spaces within Webb House. This work was supported by a grant from the National Trust for Historic Preservation‘s Cynthia Woods Mitchell Fund for Historic Interiors. The resulting information was used to repaint the Washington Chamber in as historically accurate a color scheme as possible. However, we still needed to complete paint analysis in other areas of the house, as well as the exterior. Thanks to our Save America’s Treasures grant, we are now able to do so.
July 11, 2005 – The scaffolding arrives!
In order to more closely examine the brick-end of the ell, the Museum has hired scaffolding for a month. During this period, staff and consultants will take mortar samples, count bricks, and try to understand the “shadows” left by previous architectural features.
One of the most important documentary records created during the Historic Structure Report will be a complete set of high-quality black and white photographs of the Webb House as it currently appears. The HSR team has brought in David Bohl, an experienced architectural photographer from greater Boston. Rather than commissioning expensive elevation drawings, the Museum will rely on David’s large-format photos to provide reference images for future stewards of Webb House. The photography process began on July 14 and took a total of four days.
Staff and members of the HSR team have long wondered about the original appearance of Webb House’s best bedchamber, known as the Washington Chamber. Despite having performed paint analysis in December 2000, the paint scheme on the woodwork never looked quite “right.”
Architectural conservator Brian Powell was inspired to take a second look. What he found resolves the mystery, and also reveals just how special the Webb House really is. In the 18th century, the woodwork in the best chamber was faux painted to look like cedar, a technique called, “graining.” The effect in combination with the flocked wool wallpaper must have been stunning. If the graining substantially survives under the subsequent layers of paint, it would be the only known example of an 18th century interior that retains both wallcovering and graining.
One of the issues that occurs when studying old houses is that not everything we want to see is visually accessible. Sometimes we have to drill holes, remove moldings, lift floorboards, or try other measures to see what’s hidden. Occasionally, even these methods don’t show us what we need to know.
Fortunately, there are some high-tech solutions to this problem. The Webb-Deane-Stevens Museum was fortunate to receive the loan of an industrial endoscope from Olympus Corporation in order to explore the Webb House’s more persistently hidden mysteries. An endscope is a tiny video camera with a light on the end of a flexible cable that can be snaked into a hole or crack in order to see what’s inside. This is basically the same technology that’s used for medical explorations and surgeries. Our endscope was even equipped with a JPEG digital camera that allowed us to photograph some of these hidden spaces.