Harriet Bridgeman: The first lady of fine art

She owns more than 300,000 works by great artists from Da Vinci to Monet – or, at least, she retains the rights to reproduce their images. As Harriet Bridgeman's incredible art library celebrates 40 years, John Walsh meets its charismatic chief curator. Plus, she picks her favourite 'acquisitions'.

History's record of great librarians is an eye-opener; so many became librarians on their way to becoming something else: Benjamin Franklin, Mao Zedong, J Edgar Hoover, Lewis Carroll, Jorge Luis Borges and Pope Pius XI all put in the hours of collating, taxonomising and lending before going on to conquer worlds. Some came to it late: Giacomo Casanova forsook his life of spying, swigging and shagging to run the Duke of Waldstein's library in Bohemia, Marcel Duchamp gave up Cubism and art subversion to be curator at the Bibliothèque Sainte-Genevieve. There aren't, you'll notice, many women in the list of librarian superstars; but one woman's name will surely be inscribed in future curatorial history: Harriet Bridgeman.

Her brainchild is the world's leading commercial art library. It gives its clients online access to images of over 300,000 artworks (and 750,000 historical photographs) held by the world's top galleries and museums in 8,000 locations. It has the most comprehensive system of cross-referencing imaginable. If you want 50 different images of The Last Supper, the library will track them down in seconds. If you want all three versions of Gérôme's Pygmalion and Galatea, they'll find them. If you want the complete works of Velazquez or Van Dyck, they're the guys to call. Their elaborate indexing system records the artist, title, gallery and date of each picture, but also its theme, genre and significant details – type of clothing, breed of dog, genus of plant, date-specific historic events, usefulness as period 'reference'. They license the rights to reproduce images for commercial use by publishers, greeting-card manufacturers, and movie studios in search of the right sword-and-buckler outfit in Pirates of the Caribbean. Check out the 'permissions' line on the back of any Christmas card with a Nativity scene, and you'll find the Bridgeman Art Library's name. Look at the illustrations in any biography of an artist in the past 30 years and the library's name will appear 19 times out of 20.

This spring, Viscountess Bridgeman celebrates 40 years of constant travel and the patient accumulation of the reproduction rights to the world's art. Though her empire is global, her headquarters are modest. The Library occupies a space just off Westbourne Grove, west London. In a sunlit atelier of Vermeer-like tranquility, a score of young art graduates, mostly women, sit at computer screens, fielding requests for pictures from around the world, asking a Dresden gallery if they mind having their Cranach nude featured on the cover of a retro-punk CD, telling a private caller that no, sadly they haven't any paintings of "a typical Roman Christmas".

Overseeing their endeavours, Harriet Bridgeman resembles not so much a tough, monopolistic entrepreneur than an indulgent mother pigeon. Clad in voluminous lilac skirts, she glides about the office, joshing, encouraging, bigging up, calming down. She shows you the ceiling-to-floor cabinets that used to house thousands of transparencies, before the whole operation went online. She introduces you to a chap adjusting the colour tones on Gérard's Daphnis and Chloe. In her tiny office, the wall-mounted artefacts include a pair of Peter Blake's Union Jack underpants (framed). Later, over lunch, she turns out to be an excellent gossip as she evokes her past, recalls which pillars of the community turned out to be "pouncers" and explains, in her cut-glass voice, how she's had "the perfect working life".

Born Harriet Turton in 1942 in Durham, she was one of four daughters educated at home. "The governess followed a home-teaching syllabus," she said, "which meant that, every month, we were sent a marvellous folder of colour reproductions with a lovely silk tassel that held everything together. It caught my imagination. It was a good way to learn." Her mother, Mary, "was very intellectual, always reading us poetry and taking us to exhibitions. I grew up with art as part of the background." Her father, Ralph, was a politician who once stood as an independent candidate against Willie Whitelaw. The Turtons were well-connected with the Anglo-Irish Protestant Ascendancy, and Harriet's childhood was filled with big houses. "I had a cousin with a romantic house in Cork called Ballynatray. He was wildly eccentric. He had a pack of hounds, and it was said that one of them had eaten a baby lying in a pram. But that was just a rumour."

She studied English and History of Art at Trinity College, Dublin and on graduation, walked into a job at The Lady, "this rather sober women's magazine that Rachel Johnson has made more interesting. It was awfully middle-class and down-market, with pictures of the bluebells in Hyde Park. I was the youngest staffer by 30 years, so I was given all the beauty samples. I remember being asked to cover 'Teasy Weasy' Raymond's wedding in Soho Square."

Just one year later, she was in more exalted company. "Somebody introduced me to Sir John Rothenstein, just retired from being Director of the Tate. He'd been asked by the British Printing Corporation to produce a new weekly art magazine called The Masters, based on an Italian journal called I Maestri del Colore. He said, 'Would you like to have lunch at the Athenaeum?'. I thought he meant the gentlemen's club, but it was the Athenaeum Hotel on Park Lane, a rather seedy place where Swedish air hostesses went."

Good heavens, I said. You don't mean he tried to... "No, no," she said, with an as-if crease of the brow, "we sat in a banquette for hours and to my amazement he asked me to be executive editor." She found herself in at the deep end. "Sir John knew a lot of interesting people – Miró, Chagall, Picasso. He had the right contacts. Some big names wrote for us. For the first issue, Herbert Read wrote on Vermeer; Roland Penrose on Miró." It must help the confidence of a 23-year-old ingenue to have the titans of the art world on her Rolodex. "It was really hard work but I was fascinated by what I was doing."

When The Masters folded, she was given three months to think up a new magazine. She decided on Discovering Antiques ("It was the time of Arthur Negus and Going for a Song on television") and, with typical efficiency, ran it from home. "I'd just got married [to Robin Bridgeman, the third Viscount of the family; they have three sons] and moved into a large house in Chelsea. The publishers hadn't much space so they said, 'Why don't you work from your house and we'll send you money to pay the staff?'." Over the next six years, she edited the antiques magazine while bringing up the babies. With two women, Helena Hayward and Erica O'Donnell, who ran an art course at the V&A, she started to publish books, and formed her own production company.

"The editorial staff were on the top floor, and 16 picture researchers on the bottom. Because it was a weekly magazine, it required a lot of illustrations. We soon realised it was very difficult to get any." Lady Bridgeman gave an unladylike snort of disapproval at how badly organised museums were at supplying images of their paintings. "The National Gallery and the Tate had skeleton picture libraries. We could send a photographer but only after the museum closed, we had to pay attendance fees, and they didn't keep transparencies afterwards. So the same pictures were being photographed several times, and museums weren't taking advantage of the only means by which they could generate income." She encountered some bizarre attitudes. "I met academics who were such purists they thought it undesirable to reproduce paintings in colour. Because one mightn't be able to reproduce the colour 100 per cent true to the original, they'd only allow black-and-whites. It didn't really make much sense."

And so the Bridgeman Art Library was born in 1972. No more would commercial image-buyers have to track down paintings at galleries and museums, visiting them one by one, camera in hand. The Bridgeman could offer a one-stop destination, offering excellent large transparencies of key paintings.

She travelled across England, visiting obscure museums, signing up their collections. How did they respond? "Some said to me, 'It's a win-win situation' because they didn't have to put any money upfront – all they had to do was bank a cheque every quarter. We promised to give them 50 per cent of every fee we received, whether it was for education or publishing or advertising." On her royal progress, she was startled by the lack of local knowledge, "the amazement of getting off a train somewhere like Preston, asking where the local art gallery was, and finding that nobody knew. It was a revelation of how uninterested we are in the treasures we have." She signed them up anyway, in Bristol, Exeter, Wolverhampton, Accrington... Her trip paid off. When the Royal Academy in 1998 exhibited Art Treasures of England: the Regional Collections, Harriet's library represented 98 per cent of them. It was, she said, "a moment of triumph".

Her library rolled across Europe, visiting galleries, acquiring collections, and discovering what had become of arts and books during the war. "One of the most tragic stories I heard was about a castle near Prague that housed an extraordinary collection of books dating back to the Dukes of Habsburg. The Nazis invaded the library, pitchforked the books out into carts and took them away to burn, all these wonderful, irreplaceable manuscripts. The librarian was so heartbroken, he flung himself out the upper window and committed suicide. The barbarity of it sticks in my memory."

She gradually wore down the defences of Mark Getty, owner of Giraudon, the 125-year-old archive of French art ("they've photographed the Louvre and all the provincial galleries") and persuaded him to sell it to her. She opened offices in France, Germany – and America, where her only rival is Art Resource, run since 1968 by Theodore Feder, and able to boast 450,000 fine art images from around the world. "But we represent four times as many of the American museums as they do," said Harriet. "We've done incredibly well."

So well indeed that she has found herself invited across the pond to have her brains picked by the Yanks. "I was asked to go and talk at a museum in Kansas. I felt like that painting – And When Did You Last See Your Father? – as I sat facing 16 people at an enormous table, telling them what we were doing in England and how new technology was coming to our aid. It felt amazing that I should be talking to a superpower, way ahead of us, about such things. But they've been very slow in coming to the table."

She herself shows few signs of slowing down. In 2006, a year after being voted International Business Woman of the Year, she set up the Artists' Collecting Society to streamline the collection of royalties on Artists' Resale Rights – so that, every time an artist's work is re-sold on the commercial art market, the artist gets a percentage of the sale price. Unsurprisingly, many big-name artists clamoured to be represented – especially after Lucian Freud received £22,000 in extra royalties over six months.

Everyone, you see – all the galleries, all the museums, all the artists – wants to be in Harriet's gang. Everyone wants to have this shrewd, persuasive, rather raffish British aristocrat on their side, handling the copyright to their artworks, cutting deals with the image-making world, insisting on fairness for all, bringing the finest of fine arts to the biggest possible audience. Just as she once had beautiful images delivered every month to her door – as if by magic, bound with a silk tassel like a gift from the gods.