A Tom Thomson painting that was given away as a gag gift just months ago has sold at auction for nearly half a million dollars.

TORONTO—A Tom Thomson painting that was given away as a gag gift just months ago has sold at auction for nearly half a million dollars.

Until recently, “Sketch for Lake in Algonquin Park” was collecting dust among a pile of artworks in Glenna Gardiner’s Edmonton basement.

The 71-year-old retired nurse says she used to laugh off her late father’s claims that the painting was created by Thomson, often considered the forefather to the Group of Seven.

Gardiner told StarMetro in May that she remembered the “dull” landscape image from childhood. As a kid she didn’t understand why her dad cared so much about the painting, which he insisted was a Tom Thomson piece. When she got older, and learned how famous Thomson was, she assumed her dad had been joking about the piece’s origins.

“I inherited it from my father. When he died there was a bunch of paintings left over, and my sister took what she wanted, and I took the leftovers. This was one of the leftovers,” she said.

It became a running joke between Gardiner and a longtime friend when they came across the painting while reorganizing Gardiner’s basement. Her friend insisted it could be “worth something,” leading Gardiner to present it to her.

“I sent it to her as a gag and said she was the only person that had been interested and if it was worth anything we’d go on a cruise. I had mailed it down, which I (later) discovered you’re not supposed to do with a good painting.”

Eventually, it was brought to Heffel Fine Art Auction House for appraisal, where experts verified its pedigree and valued the sketch at between $125,000 and $175,000. That turned out to be a very conservative estimate.

It sold at auction in Toronto on Wednesday night for $481,250.

Thomson did the small 18 by 25 centimetre “sketch” on site at Lake Algonquin in northeastern Ontario in 1912 or 1913, and later produced a larger version, which is now held by the National Gallery of Canada in Ottawa.

“Out in the field he would do the oil sketches, and the (larger) canvases were studio works,” said Charlie Hill, a retired curator from the National Gallery of Canada.

Hill said discoveries like this are rare because most of Thomson’s art is now accounted for. However, he thinks it’s likely a few more previously unknown Thomson pieces will surface in the coming years.

Wednesday’s auction of 118 works — which raised a total of $14.1 million — included pieces by Paul-Emile Borduas, whose 1956 masterpiece “Figures schematiques” led the auction by fetching $3.6 million — an auction record for the artist.

“Morning, Lake Superior” by Group of Seven founder Lawren Harris sold for $1.1 million — far above the pre-sale estimate of between $100,000 and $150,000. The small work is described as a preparatory sketch for a pivotal canvas by the artist, hanging in the Montreal Museum of Fine Arts.

Other Group of Seven paintings offered in the auction included A.J. Casson’s “Farmhouse Near Wingle.” The canvas also sold well over the pre-sale estimate at $541,250 (est. $150,000 — $250,000).

By The Canadian Press – With files from Tessa Vikander, StarMetro