Training in conservation actions–showing surface cleaning tools and techniques. Photos courtesy of Melissa Carrillo and Joey Shuker, 2018.

World of Maps Project - Preventive Conservation Actions

Explore our interns’ new techniques for preservation of maps at NMNH: a map transportation tool, a rehousing plan, and training for volunteers.

This post is one of two complementary features. Please also read Joanna Shuker’s insights, which will be hosted on the Smithsonian Libraries Unbound blog on March 5.

In recent years, the World of Maps project has performed the massive task of cataloguing and digitizing valuable maps housed at the National Museum of Natural History. Much of this work would not be possible without the valuable participation of volunteers and interns. Due to the importance of the collection, and to support the preservation work that has already been accomplished, the Smithsonian Institution Archives, Smithsonian Libraries, and the National Museum of Natural History together applied to the Smithsonian Women's Committee for a grant. The funds provided by the committee included stipends for two graduate conservators, including myself, to carry out a plan of preventive conservation, including conservation treatment and recommendations compiled for the use of the stakeholders.

My colleague, Joanna Shuker, and I prepared a training workshop in stabilizing conservation actions to Smithsonian volunteers Jim Harle and Bob Demoyer. Jim and Bob currently catalog, physically arrange, and digitize the maps collected across the museum’s many departments. In doing so, they identify and separate the items that require specialized conservation treatment by a paper conservator to improve access and handling, and prevent loss through deterioration. The objective of the training was to provide knowledge and tools to the volunteers to further develop their basic skills, which include simple stabilizing mends and surface cleaning with appropriate tools such as soft brushes and soot sponges. Additionally, preventive conservation practices, like handling during transportation and housing maps, were improved. The interns also developed and fabricated a map carrier to improve safety during transport through the museum, and trained Bob and Jim on technical equipment such as polyester welding tools for creating custom enclosures for fragile items.

Two photographs side by side. In the left photograph, two men stand over a large document as a woman

Map Carrier

The interns created the map carrier to transport large maps between their unit-based storage locations and processing areas for conservation and digitization. Previously, the maps were transported in paper folders, that do provide a basic level of protection, but do not have enough rigidity to protect the maps from being squashed or bumped on its ends. The map carrier is a simple, indexpensive, and easy solution. It was designed to support a folder in a gentle U-shape, yet rigid enough to prevent crushing. It is also easy to  carry, one-handed, and maneuver through narrow corridors. The step-by-step instructions for the map carrier construction are developed and will be available to archives and conservation community via STASH-c (Storage Techniques for Art, Science and History) in Spring 2019.

A woman stands holding a large document that is semi-rolled. The document has two handles.


The interns and volunteers worked together to find the best solutions to rehouse the collection. The maps are catalogued well, but has some physical storage issues, including poorly positioned items due the differences in sizes, formats, and materials in the drawers. The maps were historically stacked in flat file drawers without further compartmentalization and protection. This can cause long-term damage, since the maps constantly slide inside the drawer when it is opened and closed. Pulling out individual maps from beneath others without lifting out the maps above, and drawer vibration can cause maps to slide or roll to the back of the drawer, causing deterioration in the form of tears, losses, creases, and crushing folds. Furthermore, with both small and large maps, order and organization can be affected, which puts the maps at risk of being displaced in our records, as they can become more difficult to reach, change positions, and even slide over the back edge of an overflowing drawer, either due to carelessness or because they just slip.

The solution was to rearrange each drawer using 20-point paper folders (lignin free, buffered) that offer protection and allow the team to better handle the maps by compartmentalizing the drawers. The dimensions of the two sizes of flat file drawers (A: 50” x 38” and B: 43” x 32”) in the various departments allowed for three standard folder sizes and diverse physical arrangement:

  • Large 48" x 36
  • Medium 40" x 30
  • Small 24" x 36

The large and small folders are for the A size drawer and medium folders for the B size drawer. The fold should be facing the back of drawer to retain and prevent sliding of individual maps into and above the back wall of drawer. It also allows groups of maps to be lifted out by the folder, in order to access the one required, rather than tugging on and overhandling adjacent maps.

Two graphics of one large and one small folder. The color of the top of the folder is small but the

The recommended method of organization for a mixed-size collection is to arrange each drawer in size order. The maps will be stored in numbered folders, in groups of between ten and twenty-five maps of similar size folders. Large folders will be kept at the bottom of the drawer, and two small folders could be placed alongside one another near the top. The original order of the drawer content list should be respected as much as possible. As the maps were already numbered in order within the content classification by drawer, upon reorganizing the maps into similar sizes, it is recommended that the collection item record in the database be updated with a folder location within the drawer, and a new content list be printed for the drawer to aid researchers.

The annotated or fragile maps were given an extra layer of protection with 4-mil uncoated polyester terephthaltate film (Mylar® or Melinex®). For our project, we determined that three standard sizes of polyester L-sleeve, based on the most common size of the maps in the collection, were the best option. Where necessary, custom sizes of polyester sleeves can be created by the volunteers using the materials and equipment available for the project. This takes more labor, but customization is sometimes needed for complex folded, or shaped, maps.

 The polyester standard L-sleeve sizes include:

  • Large 32" x 42"
  • Medium 24" x 36"
  • Small 15" x 24"

An interesting variation on our storage recommendation, is maintaining original context and use. In some cases, maps that were created to be folded should stay folded, and for their appropriate storage, a custom polyester pocket strip was designed, to keep these smaller sized objects from moving around in the drawers and becoming lodged underneath other maps.

Two images of a diagram. The image to the left has a map inside of a clear folder. One of the folder

Lastly, the information compiled during the internship, including preventive conservation guidelines, preservation stabilization tutorials, and more, was assembled as a preservation manual for The World of Maps project, to serve alongside the collection’s robust cataloging manual for future volunteers. This is currently being edited, and we hope to make it available for users in the future.

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