Conserving a Ming Dynasty Map Made in Japan (Video & Photos)

This article tells the story of how the Denver Art Museum conserved this map. To learn more about the map itself read this article. No longer on view.

History, Artistry & Science

Traditional conservation embodies what I like to refer to as the “holy trinity” of disciplines: history, artistic competency, and science. The marriage of these three areas make conservation stand apart from restoration—or simply making something look good or better.

History includes an understanding of the artist’s or maker’s intent and methodologies: their materials, manufacture, and process.

Artistic competency includes manual dexterity, color matching, and experience with the working properties of materials and application techniques.

The science aspect of conservation focuses on chemistry and physics, the composition and appearance of materials, how they deteriorate and how to slow that down. Technical and analytical tools and methods are often employed for identification of materials.

Photo Documentation

Photo documentation, or getting a visual record of the physical condition, is another step of conservation treatment. Typically the front and back are recorded before treatment. However, some of the painted colors were unstable as indicated by the cracked appearance and associated losses.

In addition to the creases being folded, there were numerous edge tears and areas of lifting between the primary and secondary supports. The map had unstable areas in the colorants: the gold, silver, and shell white had areas of flaking, lifting, and loss. In addition, the silver has tarnished to black. The copper-based pigments had literally disintegrated the paper in some areas.

Conservation Steps

How we were going to maneuver the map as well as reach the central areas needed to be considered.

We attached 3-inch foam tubing to the edges of the table so that the map would have a smooth, soft surface to drape against.

A large round “Sono” tube was wrapped with Marvelseal, an aluminum laminate. Rolling made it possible to safely turn the map from front to back as well as provides safe storage when not on display.

The unstable areas of media were consolidated using funori , a polysaccharide mucilage found in certain seaweed. Funori is cooked and diluted into a liquid state. Its adhesive properties and unobtrusive visual characteristics are well suited for consolidation of this media. It is typically warmed on a hot plate and applied by brush.

Following consolidation, a facing material was applied to where the copper-based pigment had corroded the paper, leaving it brittle and fragile. We used a lightweight cotton paper—more like a tissue—that had a heat-activated adhesive applied to one side. A warmed tacking iron was used to set the tissue in place.

For the purposes of this post, I have broken out the following treatment steps into individual phases although many were done in a simultaneous manner.

The creases were humidified using layers of spun polyester interleave, Gore-tex, damp blotter, and polyester film. Once the paper was relaxed and expanded we were able to open up the creases and folds and place them under dry blotter and weight to dry. We worked first on the front, then on the reverse.

On the reverse, we reinforced the creases using narrow strips of Japanese paper and wheat starch paste. This step was done in conjunction with humidification and flattening.

There were also old repairs on the reverse that had to be removed. The sticky, brown repair adhesive was softened by humidification using Gore-tex. The repair paper was mechanically removed using a stainless steel spatula and tweezers. The remaining adhesive residue was removed with the aid of a nylon spatula and absorbing with damp blotter.

Similar weight Japanese paper was carefully shaped to the area of loss and set in place using wheat starch paste.

We compensated for loss of color in damaged areas and to newly repaired areas of loss using pastel pencil. This material was selected for its matte appearance and good blending qualities.

The duration of treatment consisted of two full-time conservators and an assistant working on for just over two weeks.

The cedar box the map was stored in.

The map before treatment under normal light.

The map before treatment under raking light (light shining from left to right).

Before treatment, the map shows loss of copper colorant and an old repair.

Foam backer rod.

Staff rolling the map onto Sono tube.

The funori used to consolidate unstable areas of the map.

Setting Japanese paper repair in place by gently tamping with a brush.

Humidification of creases.

Reinforcing strips on reverse side of map.

Reinforcing strips on reverse of map.

Removing old repairs.

Removing old repairs.

Similar weight Japanese paper was carefully shaped to the area of loss and set in place using wheat starch paste.

Compensating for loss of color in damaged areas and to newly repaired ares of loss using pastel pencil.

Dried repairs in place.

Conservator Jennifer Parson doing color compensation to repaired area.

Sarah Melching doing color compensation.

The map after treatment.

two photos of the cedar box that stored the ming dynasty map; one view of the top of the box and one view from the side
photo of the map before treatment under normal light
Ming Dynasty map under raking light
close up of Korea showing loss of copper colorant and an old repair
Foam backer rod
Staff rolling the map onto the Sono tube
Funori package
Setting Japanese paper repair in place by gently tamping with a brush.
humidification of creases
reinforcing strips on reverse
reinforcing strips on reverse
removing old repair
removing old repair
Filling losses
Filling losses
drying repairs
Conservator working on color compensation
Sarah Melching working on color compensation
Ming Dynasty map after treatment