A collection of more than 2,000 Annie Leibovitz photographs was donated in 2013 to the Art Gallery of Nova Scotia. Leibovitz is seen here at the Brooklyn Museum of Art in 2006. (Timothy A. Clary/AFP/Getty Images)

It was an enormous coup for a modest gallery with a limited budget. Four years ago, the Art Gallery of Nova Scotia announced a Toronto family was donating more than 2,000 prints by Annie Leibovitz, one of the most famous photographers in the world.

But four years later, a collection valued at $20 million and which includes some of the New York artist's best-known works — John Lennon and Yoko Ono embracing just hours before he was killed; a nude and pregnant Demi Moore — remains hidden in the Halifax gallery's storage.

As questions swirl around why the work has never been exhibited, CBC News has learned how it's become caught in a complex quagmire with financial implications worth millions for the family that made the donation and for Leibovitz herself.

It's also raised the prospect the photographs may never hang on the gallery's walls.

Leibovitz's portrait of Dan Aykroyd and John Belushi as the Blues Brothers is projected on a wall at the donation announcement at the Art Gallery of Nova Scotia on June 6, 2013. (Andrew Vaughan/Canadian Press)

Documents show that what was initially touted as a "transformative" philanthropic gift to the gallery was also flagged by the Canada Revenue Agency as a potential tax shelter that could profit the donors.

The tax implications were an early feature of an impasse involving a little-known Canadian tribunal that certifies cultural donations for tax purposes — a board that has ultimately questioned whether the collection by the celebrated portrait photographer is of "outstanding significance and national importance."

The Canadian Cultural Property Export Review Board's repeated refusal to certify the bulk of the Leibovitz photos as "cultural property" has not only alienated her, but has also deprived her of nearly $2.5 million US, CBC News has learned.

"This has been a difficult and frustrating situation for everyone involved, especially for Annie, who has witnessed her name and her artwork denigrated," Harley Mintz, a member of the family that bought the collection from Leibovitz and donated it, said in an email to CBC News.

A representative of Leibovitz said the artist was not available for an interview, nor could a representative speak for her.

But Mintz said Leibovitz has only been paid half the $4.75 million US purchase price and that their agreement dictates she will receive the second half only when the review board certifies the work.

Then-Nova Scotia premier Darrell Dexter and then-culture minister Leonard Preyra at the Leibovitz collection announcement. (Andrew Vaughan/Canadian Press)

While Leibovitz is currently out millions of dollars, she retains copyright over the collection, according to documents obtained by CBC News.

The Art Gallery of Nova Scotia won't detail precisely what that means, but Nancy Noble, the gallery's current CEO, said artists can generally dictate how their work is displayed and marketed.

The decisions by the review board, Noble said in an interview, "kind of distanced the artist from not just the Art Gallery of Nova Scotia but from Canada as a whole."

"When a quasi-judicial governmental board says your work's not nationally or culturally significant, obviously that's going to have some impact," she said in an interview.

A photo of Queen Elizabeth by Leibovitz is displayed at the 2013 announcement. (Andrew Vaughan/Canadian Press)

Documents filed in the Federal Court of Canada offer insight into the financial arrangements behind the Mintz family's 2013 purchase and the subsequent donation to the gallery.

The documents, which are part of a discontinued legal action launched by the family related to the review board's decisions, show:

That just days before the donation was made, the Canada Revenue Agency noted it as a potential tax shelter, raising the prospect that a numbered company controlled by the Mintz family might end up turning a profit by giving the collection away.

That a draft sales agreement indicated the numbered company would pay Leibovitz $4.75 million US for the prints, but that half the money was contingent on what valuation the work would be given by the Canadian Cultural Property Export Review Board.

That the sale went through April 1, 2013, and the Mintz family donated the prints to the Art Gallery of Nova Scotia two days later.

That following the donation, the gallery tried to have the prints certified by the review board at a fair market value of $20 million, based on three appraisals — more than four times the purchase price in the draft agreement.

That had all the work been certified and the fair market value of $20 million been approved, it may have led to a tax refund/credit for the Mintz family up to double what they paid for the collection.

That the board initially refused to certify any of the collection. After a second application, it only certified 762 unpublished "file prints" that documented the artist's process, and valued them at $1.6 million. It rejected the bulk of the collection — 1,300 photos.

Notes taken by a senior adviser to the review board during its second deliberation on the collection suggest board members were concerned about several things, including whether the work was of "outstanding significance" to Canada.

The adviser also wrote: "Motivation here is to make a tax grab — motivation is key — this is tax package stuff — made for financial not artistic reasons — this is NOT the same as everything else."

The Art Gallery of Nova Scotia in Halifax. (Brian MacKay/CBC)

Mintz has previously said he'd been introduced to Leibovitz through a mutual friend and began to discuss acquiring the collection as a way for his family to honour his mother, Faye Mintz, who had died two years earlier.

In his email Tuesday to CBC News, Mintz said it's "simply unfair" to characterize his family's donation as a "tax grab." He said his family was approached in December 2012 by "knowledgeable art-world figures."

"We were asked to help facilitate a major gift to the Art Gallery of Nova Scotia that would provide it with a unique collection of art from one of the world's most-praised photographers and that is exactly what we did," said Mintz, a tax expert and partner at accounting firm Deloitte LLP.

"Instead of being celebrated, it has been met with resistance, for reasons that we do not understand."

Harley Mintz poses with a book of Annie Leibovitz photos on June 11, 2013. (Vince Talotta/Toronto Star via Getty Images)

At the heart of that "resistance" is a tribunal most Canadians have likely never heard of, but whose impact is on display across the country.

Its aim is to protect the country's artistic, historic and scientific heritage and bring it to the public by encouraging owners of "cultural property" to donate it to galleries and museums, many of which would never be able to afford to purchase the work.

The Canadian Cultural Property Export Review Board handles about 500 applications a year from designated institutions and certifies more than $200 million worth of cultural property annually for income tax purposes.

Members of the review board are appointed by the federal cabinet and include art and legal experts, gallery directors, dealers and collectors.

Their role is to determine whether cultural property is of "outstanding significance" and "national importance." If it meets those thresholds, the board then determines fair market value. That value represents a significant tax break for the person making the donation, according to charity lawyers who spoke with CBC News.

"It's one of the few double dips, if you will," said Florence Carey, a Winnipeg lawyer who specializes in charity law. "I have no capital gain, which would otherwise arise, plus I get the full tax credit. It's a very attractive way of dealing with property from a tax perspective."

Leibovitz takes photos during a media preview ceremony prior to the opening of an exhibition in Moscow in 2011. (Sergei Karpukhin/Reuters)

The review board refuses to discuss the Leibovitz collection, citing privacy laws around individual income tax information.

But the chair of the board, Sharilyn Ingram, said it can certify pieces created by non-Canadians. The criteria are the same for Canadian-made property, but she said there are sometimes greater challenges for foreign work.

"We're trying to assess value to Canadians," she said. "And obviously Canadians don't exist in a hermetically sealed border, thank God. We connect to the world at large. And therefore something that has significance more broadly can certainly be relevant within Canada."

Ingram joined the board last year and said during her tenure there have been no donations that are tax shelters.

That's likely because in 2014, just months after the review board made its second decision on the Leibovitz collection, the federal government changed the Income Tax Act related to donors using the review board for such endeavours.

In an advisory in June 2014, the review board said it had become "increasingly vigilant" about tax shelters, saying they could be used "to obtain unjustifiably high tax benefits, essentially turning what was intended to be a charitable donation into a profit-making venture."

Leibovitz strikes a pose during the launch of her international exhibition tour in London in 2015. (Andy Rain/EPA)

The Art Gallery of Nova Scotia sent a third application to the board, but it again rejected the bulk of the Leibovitz collection in the fall of 2014.

Noble said in that case, the board did provide a "large document" detailing its reasons. She declined to share it with CBC News, but said the gallery disagrees with the assessment.

"We believe that [Leibovitz] is a significant artist who has contributed significantly to photography and is artistically and culturally significant to Canada and the rest of the world. And they disagreed with that so they didn't certify it."

The decisions by the board have also perplexed one longtime Toronto art lawyer who reviewed the Federal Court documents that provide information about the first two applications.

"I really think the board screwed up," said Aaron Milrad. He said the board was "picking and choosing" what it certified, and called the collection a "treasure trove" and a "fantastic opportunity for Canada" that would be appreciated by the public and studied by researchers and students.

The Rolling Stone magazine cover from Jan. 22, 1981. Leibovitz's photo of John Lennon and Yoko Ono was taken just hours before Lennon was fatally shot on Dec. 8, 1980. (The Associated Press)

There is also a plausible reason why someone could purchase a collection for $4.75 million, but have it appraised at fair market value at $20 million, Milrad said.

Fair market value, according to the review board, was defined as the highest price that could be fetched in an "open and unrestricted market, between a willing buyer and a willing seller who are both knowledgeable, informed and prudent, and who are acting independently of each other."

Milrad said that wasn't the case with Leibovitz, who faced well-publicized financial difficulties in 2009.

"This was not an ordinary sale," according to Milrad. "It was a forced sale at a time of financial difficulty, so it was well below market.

"And I have no difficulty, frankly, with the appraisals. I know the names and the work of two of the three appraisers and they're highly respected. Very knowledgeable. And they're looking at what is the worth of the work in its proper form and its proper market."

Portraits of William S. Burroughs are seen during a preview of an exhibition of Leibovitz's work in 2006 at the Brooklyn Museum. (Mary Altaffer/AP)

Noble, the current gallery CEO, said the gallery recently submitted a fourth — and final — application to have the bulk of the Leibovitz collection certified.

She said she is optimistic the cultural review board will see the light and expects a decision in the coming weeks or months. A new person from the art gallery has drafted the application, she said, and there are new members on the review board.

If certification comes through, she said she hopes it will help "bridge the distance" with Leibovitz "so we can work with her and her management team to create a great exhibition of this exciting collection for Nova Scotia and Canada."

Noble is more circumspect about what will happen if the review board once again rejects the collection.

"I don't have a full answer for that," she said. "We will be obviously consulting with the artist and her team and the donors and to have a conversation and see if we can figure out a way to move forward without that certification."

Leibovitz looks at an exhibition of her early work at the Zurich-based nonprofit LUMA Foundation outpost at the Parc des Ateliers in Arles, southern France, on May 24, 2017. (Boris Horvat/AFP/Getty Images)

She said the Art Gallery of Nova Scotia owns the collection outright and that the Mintz family cannot take it back. She also confirmed they have not stood in the way of it being exhibited.

When asked if the gallery could sell the collection, she refused to confirm if that would be allowed.

"The whole process from the beginning was to get the collection certified so that we could then work with the artist to create some kind of show to travel nationally, that we could show it to Nova Scotians and share it with the world," she said.

"It's an amazing collection of photographs."