How a precious blueprint of the Bloor Viaduct got a makeover at the Toronto Archives

How a precious blueprint of the Bloor Viaduct got a makeover at the Toronto Archives

Click to see a larger version. (Image: Kayla Rocca) Click to see a larger version. (Image: Kayla Rocca)
 

The Prince Edward Viaduct—better known as the Bloor Viaduct—has been around for nearly a hundred years, but its blueprint looks almost as good as it did the day it was created. The 1913 document, donated in 2014 by the grandchildren of viaduct designing engineer Thomas Taylor, owes its pristine appearance to Sarah van Maaren, a conservator at the Toronto Archives, whose job it is to turn every piece of folded, ripped and dirty paper back into an artifact the city can be proud of. Here’s a look at all the tools and materials she uses.

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Before treating an object, a conservator fills out a condition report. “You need to state its original condition so that if something goes wrong you have proof of how it looked before,” van Maaren said.

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To avoid removing the blue-coloured dye, van Maaren gently cleaned the print using a vulcanized rubber sponge. She worked from the middle to the outside, lifting away the dirt in small sweeping movements. “Because blueprints are so touchy and sensitive, I didn’t do anything to remove the staining or discolouration along the sides,” she said.
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Van Maaren used a Staedtler Mars eraser to remove some dirt from less sensitive parts of the blueprint. She moved the eraser in tiny circles to avoid damaging the paper. “Cleaning takes about half a day, but it depends on how dirty something is,” she said. “Often with blueprints, they were stored in basements or places that had coal-burning furnaces, so you always have lots of black on them.”
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After she’d finished removing the dirt, van Maaren set about uncurling the page. “The blueprint came loosely rolled with fold creases, so I had to introduce moisture back into the paper to flatten it,” she said. She made her own humidification chamber by layering plastic, wet blotting paper, Gore-Tex and pieces of Reemay on both sides of the blueprint. The plastic trapped in the moisture while the Gore-Tex slowed down the introduction of water from the wet blotting paper to the blueprint.
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After about 20 minutes, van Maaren removed the blueprint from the humidification chamber and placed these beanbags on it to hold it flat. She left it under the weights for about a week.
Click to see a larger version. (Image: Kayla Rocca) Click to see a larger version. (Image: Kayla Rocca)
 
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Next, van Maaren turned to her supply of Japanese paper—a chemical-free material that conservators use to fix tears. Instead of cutting the stuff with scissors, she used a water brush pen, which weakened the paper so she could easily rip off the piece she needed. “I don’t cut it, because the long paper fibres help it adhere properly to the blueprint,” she said.
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Van Maaren applied wheat paste to the Japanese paper using a strip of Mylar. “You don’t want to use too much of it on the actual piece,” van Maaren said. Excess glue causes “tide lines,” ugly moisture marks that give the paper a waterlogged appearance.
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She used the smooth edge of a bone folder—a long, flat piece of bone that looks like a letter opener—to press down the Japanese paper for better adhesion. While folders can be made out of Teflon, van Maaren prefers the classic cattle bone.
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Van Maaren placed a piece of Reemay, some blotting paper and a beanbag on top of the glued-down Japanese paper to hold it flat while it dried, which took about 10 minutes. (The Reemay prevents the blotting paper from sticking to the glue as it dries.) After the whole process was complete, the blueprint went into the Toronto Archives’ collection for public viewing. It’s in fonds 89, file 6.