More than a dozen works by Group of Seven member A.Y. Jackson are being sold at auction this week, put on the block by the Art Gallery of Ontario.

But why would one of Canada's major art galleries ever get rid of artworks, let alone pieces by one of the country's best-known artists?

The practice is called deaccessioning — and it's not without controversy in the art world.

What is deaccessioning?

When a museum or gallery adds an object, it's called accessioning. The process involves a thorough analysis of everything to do with the piece, including its physical condition and legal ownership. Once that's done, the item is assigned a number and officially logged into the institution's permanent collection.

Think of deaccessioning as the reverse. It's when a cultural organization decides to cut an object from its permanent collection.

A gallery might transfer a deaccessioned painting to its education department for use in art classes, or give the piece to another institution as a gift, or even return it to the original donor. The most lucrative option is to sell the piece at auction.

Why would a museum want to get rid of art?

What you see on display at a gallery or museum is just the tip of the iceberg. They typically have a vast collection stored away — only a fraction of it is ever on display at any one time.

Maybe an object no longer fits with a gallery's mandate. An artifact might be in extremely poor condition or deemed lacking in historical importance for continued preservation. Perhaps an item is subject to a new ownership claim.

This undated photo shows A.Y. Jackson looking over one of his paintings hanging at the McMichael Canadian Art Collection in Kleinburg, Ont. (Blaise Edwards/Canadian Press)

Deaccessioning tends to make headlines when a museum does so for financial reasons — to raise money for new acquisitions, for instance, or to cover its operating costs.

At the AGO, which has been attempting to diversify its collection, staff felt A.Y. Jackson was a prime candidate for deaccessioning, said Georgiana Uhlyarik, the gallery's curator of Canadian art.

Despite removing 20 pieces to be auctioned — 17 this week and three more in the fall — the AGO will still have nearly 150 Jackson artworks in its collection. Uhlyarik says the Group of Seven artist is also well represented in sister galleries: the McMichael has more than 400, the National Gallery more than 700 and the Ottawa Art Gallery has nearly 300.

Can a gallery just sell anything it wants?

Not necessarily. There is usually a long list of steps to be followed.

Most institutions belong to umbrella groups, such as the Association of Art Museum Directors or the Canadian Museums Association, that have specific policies and guidelines governing the deaccessioning process. Established museums often have their own policies as well (the AGO's is here).

The oil on canvas painting Laurentian Hills is one of the 20 A.Y. Jackson works deaccessioned from the AGO's collection. It will be offered at Heffel's spring auction on Wednesday. (Heffel Fine Art Auction House) This label on the reverse of Laurentian Hills shows that it was accessioned by the AGO in 2002 and deaccessioned in January 2019. (Heffel Fine Art Auction House)

These policies typically lay out the specifics of how to proceed, including which groups must be consulted during the process, how transparency should be maintained, and in some cases, what sanctions might befall institutions that break the rules.

According to the AGO, its recently deaccessioned A.Y. Jacksons were carefully considered by curators and other staff, presented to different committees, and underwent multiple levels of approval before being offered to sister institutions within Canada. After that, they were sent to auction.

What happens to museums that don't follow the rules?

When deaccessioning goes wrong, it can have serious repercussions, from damage to an institution's reputation to a drop in funding.

In the U.S., the Berkshire Museum in Massachusetts and the Delaware Art Museum sparked backlashes in recent years for selling major artworks to pay for expansions and boost their endowment funds. Both were formally sanctioned by the Association of Art Museum Directors, which urged its members to cease loans, collaborations and exhibitions with the two museums.

People were outraged when the town council in Northampton, England, deaccessioned and auctioned an ancient Egyptian statue in 2014 in order to fund an expansion of its museum. The descendent of the original donor launched a legal challenge that led to him receiving nearly half of the £15.8 million paid for the statue. The Northampton museum subsequently lost its membership in the U.K. Museums Association and accreditation from Arts Council England, which affected its partnerships with other museums and also led to it losing grant money.

Is it a matter of money over mission?

For institutions in financial trouble, there's an undeniable temptation to dip into collections in hopes of selling prime objects to keep the lights on and the doors open.

However, the traditional view is that institutions are caretakers of rare objects held in the public trust, and that art should only be removed to improve the overall collection.

"Museums exist to preserve objects, preserve artifacts, art, scientific specimens. Deaccessioning can jeopardize the preservation of objects and, in fact, can be an absolutely contradictory function of why museums exist," said Steven Miller, a curator, museum professional and author of the book Deaccessioning Today.

A main concern is that once sold privately, the public loses all access to cultural treasures. According to David Heffel, president of Heffel Fine Art Auction House, that's not necessarily the case. He says auction houses can be intermediaries between buyers and curators assembling exhibits.

Does the public ever have a say?

Public outcry, widespread news coverage and legal challenges can sometimes help reverse deaccessioning decisions.

The National Gallery of Canada sparked a furore last year with its plans to deaccession and sell The Eiffel Tower, one of its two Marc Chagall oil paintings, to fund the attempted purchase of Jacques-Louis David's Saint Jérôme Hears the Trumpet of the Last Judgment, owned by a Quebec parish in need of money for repairs to a historic church. The Chagall was ultimately withdrawn from auction, but woven throughout the complicated fiasco was criticism of the gallery's leadership and lack of transparency.

The National Gallery of Canada and its former director Marc Mayer came under fire for the decision to deaccession and auction Marc Chagall's The Eiffel Tower to fund the purchase of Jacques-Louis David's Saint Jérôme Hears the Trumpet of the Last Judgment. (Idil Mussa/CBC)

In 2009, a proposal by Brandeis University in Massachusetts to shut down its Rose Art Museum and monetize its art collection was met by a firestorm from students, alumni and artists. The public protest, plus a lawsuit from museum supporters, helped change the minds of trustees.

Widespread outrage also helped halt the 2014 auction of 85 Joan Miro paintings, which Portugal's government had seized as assets from a failed bank it had bailed out.

Some museums today are making fresh attempts to be more transparent and inviting the public to join in the process. For example, the Indianapolis Museum of Art has posted a database listing details of objects it has deaccessioned over the years.

Five years ago, the Georgia Museum of Art staged an exhibit and sought public input about four paintings curators had identified for deaccessioning. The museum ultimately kept two, including the public's favourite.

Money from the sale of 20 A.Y. Jackson works from the AGO will be used to purchase art for the gallery's collection of Canadian and Indigenous art, says curator Georgiana Uhlyarik. (Nigel Hunt/CBC)

The generally accepted practice today is for museums to employ deaccessioning as a tool to refine, build on and diversify their collections. That's the reason the San Francisco Museum of Modern Art gave earlier this month for selling a major Mark Rothko painting that garnered $50 million US at auction.

In the AGO's case, the money from the auction of its 20 A.Y. Jacksons — which come from its Canadian and Indigenous collection — will be used to buy art for that specific collection.

"The word curator comes from the word 'care,'" said the AGO's Uhlyarik.

"In thinking about, 'How do we care for the collection responsibly?' we have to think about, 'How do we continue to grow our collection?"