Conservators answer your questions

Nov 21, 2019

On November 4, Historic New England participated in a national #AskAConservatorDay on Twitter, a day when conservators welcome questions from the public about conservation methods for preserving historic objects.

Read on for our conservation experts’ answers to some of the most common questions.

Conservator Michaela Neiro and Mellon Fellow Ellen Promise examine jewelry and other collection objects using the Brunker portable X-ray fluorescence device. Curator Laura Johnson meets with the two conservators to discuss their findings.

Question: How do conservators deal with rust?

Answer: When iron develops a bright orange rust, it means the metal is actively deteriorating, usually from direct water contact or high moisture levels in the air. This is treated in the lab by “passivation,” or the conversion of active rust to stable iron by using tannic acid.

Conservator Michaela Neiro passivating rust to preserve objects from Beauport, the Sleeper-McCann House, in Gloucester, Massachusetts.

Question: How do historic houses preserve things like wallpaper on the walls?

Answer: At Historic New England, our conservators often find that 150-year-old wallpaper in good condition, but the 150-year-old paste is not. In this case, the wallpaper can be delicately removed as a whole sheet. Conservators work in teams to strengthen the old paper with a thin layer of strong new Japanese tissue on the back. Then the wallpaper can be re-hung using archival adhesive such as wheat starch paste.

Conservators Terry Williams and John Childs transport conserved wallpaper to be re-hung at Castle Tucker in Wiscasset, Maine.

Question: How are display mounts made for things like shoes or hats?

Answer: Conservators design a variety of custom made soft forms to help shape and support objects while on display. We use inert, archival materials such as polyethylene foam, polyester batting, and undyed cotton that are carefully shaped to not stress the object.

Conservator Megan Creamer prepares a soft internal mount for two modern moccasins made by Narragansett artist Silvermoon LaRose for display at Casey Farm in Saunderstown, Rhode Island.

Question: Why does gilding fall off of things like mirrors and frames?

Answer: Gilding is often applied to wood that is carved into complicated, rounded shapes. When the wood expands and contracts, the gilding layers can’t keep up, and fracture over time. Conservators preserve fractured gilding by using traditional adhesives such as animal glue to ensure no more gilding falls off. Then, areas of loss are filled, toned, and gilded, sometimes with new real gold.

Question: How do you know what materials an object is made of?

Answer: Conservators always start work on an object by looking very closely, since a gold-colored object might not be real gold, or a wooly pillow might not be real wool at all. One valuable tool to look very closely is a microscope, which is used extensively to identify textile fibers whether they are from a sheep, a goat, a plant, or synthetic plastics. Knowing what an object is made of is key to understanding signs of damage and long-term preservation.

If you are interested in more about Historic New England’s conservation work, join us for an exclusive tour of the lab on February 8 and ask a conservator in person! Reserve your spot today.