Conservators at the National Library of Scotland have rescued a rare 17th century wall map from the verge of destruction. Ages ago, the map was balled up and stuck in the chimney of a house in Aberdeenshire to block drafts. It was discovered when the home was renovated and someone had the foresight to save what looked like a lumpy bundle of dirty rags from the trash and donate it to the National Library.

When it arrived at the Library’s Collections Care department, it was stuffed in a plastic bag carried inside a Whyte & Mackay Scotch whisky box. Book and paper conservators carefully removed it from the bag. Its dire condition was immediately evident. It was balled up, caked with dirt and had been extensively gnawed upon by vermin and insects. Even the smallest movement would cause fragments of the brittle paper to shower down from the backing. Conservators had to unfurl it painfully slowly to keep the damage to a minimum. Even so, dirt and paper fragments flaked off and the paper was found to be severely distorted with deep creases.

Once opened, experts recognized the map as a late 17th century map of the world produced by the Dutch cartographer, engraver and publisher Gerald Valck. The map is colossal in size at 7-by-5 feet and there are only two other copies known to exist in the world. Large pieces of it had crumbled away and were irretrievably lost. Because of the map’s rarity, the conservation team worked painstakingly to preserve what was left of it.

The backing was quickly identified as the main cause of the damage. It was common in the 17th century for great wall maps to be affixed to a canvas backing for display for the delight of visitors. Dutch mapmakers were particularly prominent in the period, and large-scale maps of this time appear as elegant backdrops in the paintings of multiple Dutch Golden Age artists, including Johannes Vermeer in The Art of Painting (1666-68), now in the Kunsthistorisches Museum in Vienna. The map that hangs in Vermeer’s painting, the Seventeen Provinces of the Netherland published by Claes Janszoon Visscher in 1636, is similar in style, dimensions and age to the one found in the Scottish chimney.

There was a steep price to pay for this mounting, because canvas and paper do not respond to environmental conditions in the same way or at the same rate. The canvas of the Chimney Map was far sturdier than the paper, causing it to warp and shrink and crack. Conservators had to remove the backing for the permanent well-being of the map, but first they had to stabilize what was left of the paper map.

The map was originally printed in eight separate sections and adhered to a linen backing. It was already splitting along the joins between the sections and the decision was taken to separate the sections to make the map easier to work with. These were each placed in a humidifying chamber as the gentle introduction of moisture made it easier to flatten out the map.

Removing the backing without further damaging the paper proved to be one of the most difficult tasks. This involved using a thick cellulose solution to fix light weight Japanese paper to the front of the map in two layers. This secured the paper map while the backing was peeled off using hand tools.

The final stage of cleaning involved suspending the map sections individually in water in a heated sink at 40°C for 40 minutes with the water being gently agitated to clean dirt from the surface. On removal they were placed in blotters to remove any excess water.

In total, the restoration took 150 work hours over a period of six months.

This silent video shows paper conservator Claire Thomson at work on the Chimney Map from extrication from the whisky box to microscopic examination of fragments to the water baths to a glorious final before-and-after comparison.

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This one discusses the conservation challenges with Thomson and explores the history of the map.

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