In 1965, a young German painter was awarded a scholarship to study at the Villa Romana in Florence. This artist, then 27 years old, was born Hans-Georg Kern but a few years before his trip to Italy he had chosen to call himself Baselitz after his birthplace, a little community in Saxony. With him on his Italian journey he took a book called The World as a Labyrinth by the German art historian Gustav René Hocke.

This, Baselitz explained when I spoke to him recently, ‘was my guide, so to speak, my Bible, during my visit to Florence’. Hocke’s book, published in 1957, was a pioneering investigation of what was then almost unexplored art-historical territory: the Mannerist style of the 16th century, developed by the generation of Italian artists who came after Michelangelo, Leonardo and Raphael – at once complex, fantastic, convoluted, erotic and, at least in the eyes of some later observers, also neurotic. Baselitz’s discovery of Hocke laid the foundation for the artist’s great collection of Renaissance prints, some of which are on show in the Academy’s exhibition ‘Renaissance Impressions’, together with works from the Albertina, Vienna.

As Baselitz explains, The World as a Labyrinth dealt with ‘the paintings, poetry and music of the period’ – the entire Mannerist world. But while Baselitz was in Italy for his scholarship it was the discussion of the visual art that made the deepest impression on him. ‘It was then I discovered Rosso, Parmigianino, Bronzino, Pontormo.’

It is not hard to see the appeal. Hocke’s study, a cult book at the time, presented Mannerism as the art of a period in which ‘brain, blood and heart were in disequilibrium’. As Baselitz recalls, this was ‘a very important book for some of us students because it contained a different view of the world: it was an anti-classical book!’

It is not hard to imagine why that might have struck a chord with a painter who as a child had walked through the smoking ruins of Dresden after the fire storm, and came to adulthood in a Berlin which was itself still partly in ruins, a divided city that symbolised a Cold War world split along ideological lines. Baselitz felt an affinity with Mannerism, the product of war-torn Italy and a Europe fracturing into Reformation and Counter-Reformation.

While he was in Florence he looked hard at the artists whose work spoke to him – Pontormo, Parmigianino and their followers. When the time came to go home to Germany, he wanted to take back a record of their work. ‘Being interested in something is one thing, and wanting to own it is another. I wanted documents of that period of art, Mannerism up to about 1540, which really, really interested me.’

The first Mannerist print he bought cost 40 Deutschmarks, not much – but almost a third of his scholarship funding for a month. ‘In 1965 when I began collecting this kind of thing it was quite inexpensive,’ Baselitz explained. ‘It wasn’t particularly valued historically. Over the years, of course, the collection has become quite large, because I remained faithful to this area.’

His great interests are Mannerism, the School of Fontainebleau – that is, the Italian Mannerist style transported to France by Rosso and Francesco Primaticcio – and the chiaroscuro print. The latter, the focus of the Royal Academy exhibition, was one of the most sumptuous products of Renaissance printmakers. The chiaroscuro woodcut included different tones of the same colour, thus producing an effect close to monochrome painting. The method involves technical virtuosity, since to achieve the required result, two or even three wood blocks have to be printed on one sheet of paper, one after another, perfectly in alignment. As Anne Desmet RA explains in this issue, this medium was pioneered in Germany in the first decade of the 16th century by artists such as Lucas Cranach the Elder and Hans Burgkmair. But it was quickly taken up by Italian artists, including Ugo da Carpi, who made prints derived from the works of Parmigianino, among others.

Art history as we know it would not exist without collectors. Painters and sculptors are far from being the only ones who succumb to the urge to accumulate art, but artists such as Thomas Lawrence PPRA (who concentrated on Old Master drawings), Degas (who owned magnificent paintings by his contemporaries) and Baselitz have put together remarkable collections. Artists see art from a unique perspective – that is, they see it from the vantage point of their own work, which gives their collections a double interest. They scan both the present and the past for objects that appeal to their eyes and their sensibilities. So the fact that Baselitz is fascinated by Mannerism not only tells us something about him, but also something about Mannerism.

Did Baselitz’s print collection affect his own work? To this question, he gives a wonderfully, almost Manneristically complex reply. ‘In the first place, there’s no connection; but in the second place of course there is a connection because in 1966 I made chiaroscuro prints of my own.’ He did this, he goes on, ‘in the full knowledge that this put me in a slightly awkward position’.

‘In those days other print media were fashionable – silk-screens, lithography – those were the techniques used by “modern artists”, so making woodcuts meant I was not one of them.’ The mid-1960s was the apogee of Pop and Op artists using those techniques. ‘For me it was important to use old media but to try to do something new in them. It was a conscious opposition, stubbornness.’

In Baselitz’s case there is a clear link between the artist and his collection: it was a way of studying a historical period that fascinated him. ‘In the 1960s, I could not own a painting by Parmigianino, but I could own a print. It was less a question of price, though obviously it was that too, as a matter of what one can use. I use the prints as a sort of visual reference library.’

There are other ways of explaining the urge to collect, and other reasons why artists buy art by other people. For Tom Phillips RA, for instance, collecting is a ‘psychopathology’. The painter Howard Hodgkin has an equally debunking line on the subject, as he told me a few years ago: ‘All collecting is fundamentally the same, whatever you collect. It’s shopping.’

Yet more reductively, Hodgkin summed up ‘most definitions of collecting’ in one word: ‘greed’.

Damien Hirst, another notable artist collector, confesses that one of his own motives was to ‘try and get inside the minds’ of his collectors. ‘I thought it was a smart thing to find out what it felt like. Then you realise it’s a horrifically addictive, crazy pursuit.’

Nonetheless, all three of these artists have carried on collecting, regardless of its psychopathological, addictive or shopaholic characteristics. Hodgkin has built up a superb array of Indian miniatures, which went on show at the Ashmolean Museum in Oxford in 2012. Among other collections, Phillips told me, he has amassed ‘about 5,000 African gold weights, which is enough; it must by accident be the premier collection of those in the world’.

For his part, Hirst now owns two collections that have tended to fuse into one: a remarkable cache of contemporary art, including a number of paintings by Francis Bacon, and an updated chamber of curiosities. The architects Caruso St John are currently in the process of converting a terrace of old buildings in Newport Street, Vauxhall, into a gallery to display Hirst’s collection. It’s intriguing to discover Hirst owns works by Baselitz – and vice versa.

These examples naturally raise a question. Are they collections that just happen to have been made by painters and sculptors, or is there something special about the artist’s collection? Hirst believes that, at least, artists have an inbuilt flair for collecting.

‘I think artists are already imbued with the kind of sensibilities you need to make a great collection. Organising a collection is exactly the same as organising a painting, sculpture or any artwork. So if you are an artist you have got a leg up. Also, artists have got the bravery to go with their instincts a lot more than other people.’

He concurs with the view that one of the great inventions of 20th-century art was collage. And that putting a collection, or indeed an exhibition, together is like making a collage. When he was the curator of the ground-breaking ‘Freeze’ exhibition in 1988 (the show that first introduced the YBAs), Hirst remembers: ‘It was like a great big 3D collage, organising already organised elements, thinking a Michael Landy sculpture would look just amazing with an Ian Davenport painting; all it needs now is an Angela Bulloch light piece.’

Tom Phillips agrees, but with a qualification. ‘There’s a connection between putting a collection together and putting an oeuvre together, rather than a single work.’ Gold weights from Ghana and the Ivory Coast intrigued him because they were ‘like an inventory of the whole world – every act, every implement, everything people ate, all represented in this genre’. They had an affinity with his own work, in that they were ‘encyclopaedic’.

He completed the collection – as you might a painting or a life’s work – with a crucial touch. ‘One particular gold weight represents the act of weighing gold itself. That seemed to be the key piece. I sort of half-knew where it was, and eventually I found it. So that was the end of that collection, and I wrote a book about it.’

Hodgkin, on the other hand, is inclined to emphasise the compulsive aspect of collecting more than its imagination. ‘It is true up to a point that it’s a creative act joining together disparate things. A great collection certainly has a character of its own. But it is accumulation. That can happen to anyone if they are unlucky enough to catch the disease.’ He has suggested, however, that collecting art provides a specific solace for artists. ‘A professional artist sells what he makes. Buying art fills the void that comes as each work leaves the studio.’

If artists have some particular reasons to collect, they perhaps also have an unusual insight into what collecting truly is. Hirst has defined it with a metaphor. ‘Collecting is stuff washed up on a beach somewhere and that somewhere is you. Then when you die, it all gets washed away again.’ This suggests that the fundamental connection between the items in any collection is the collector.

Lucian Freud once put this to me succinctly. ‘In the end, nothing goes with anything. It’s your taste that puts things together.’ Hirst agreed with that thought when I put it to him, but was less convinced by another of Freud’s dicta on the subject. Freud owned a number of works by Frank Auerbach – in addition to paintings and sculptures by Corot, Cézanne, Constable, Rodin and Degas, among others. But when I suggested he was an Auerbach collector, he was a little put out. In reply, he rephrased a remark by the American writer Djuna Barnes about her relationship with Thelma Wood: ‘I’m not a lesbian, I just love Thelma.’ Lucian echoed that: ‘I am not a collector, I just love Frank’s work.’ Hirst’s response on hearing Freud’s line was, ‘I think that’s good, but it’s not true, because that – loving something – could be all that it takes to make you a collector.’

Obviously, love for a certain kind of thing is likely to be a starting point. Writing in 1991, Hodgkin confessed that he started buying Indian paintings, ‘because I thought they were beautiful’. Subsequently, however, ‘after the wanting stage has passed, usually when large amounts of money have been spent on serious acquisitions, then you make a horrible discovery that a collection has a life of its own: it makes its own demands.’

Once the ‘design’ of the collection has formed in the collector’s mind, Hodgkin related, then things have to be bought out of ‘necessity as well as passion’. That, he concluded, was the most dangerous but also the most creative phase of collecting, involving the head as well as the heart and other ‘lower organs’.

Surely, this is the truth. Collecting is at once an obsessive compulsion and – at least potentially – a creative act. It is simultaneously an addictive disorder and, as the sculptor Richard Deacon RA recently put it, ‘a way of modelling the world’. You may accumulate works of art to hang on your walls – in Lucian Freud’s words – ‘to thicken your life’ and/or because you can’t stop yourself buying them.

Germany Divided: Baselitz and his Generation is at the British Museum until 31 August 2014. Georg Baselitz: Farewell Bill is at the Gagosian Gallery, London until 29 March 2014. Damien Hirst’s new gallery opens in London in Spring 2015.

Martin Gayford is a writer and artist critic.