Thanks to the Colman family, Norwich Castle has the world's finest collection of 19th century Norwich School paintings. This great art legacy has just undergone a major revamp for the 21st century. IAN COLLINS reports.

In 1946, the year of his death, Norfolk businessman Russell James Colman presented to Norwich a treasure trove of pictures which had made the city famous in art circles throughout the world.

The gift comprised hundreds of oil paintings, watercolours and drawings by masters John Sell Cotman and John Crome and their friends, relatives and pupils, whose first exhibition as the Norwich School was held in 1805 – the year Norfolk hero Horatio Nelson met his end, and his final victory, at the Battle of Trafalgar.

As the first and the finest (and the longest-lasting) of the provincial art movements to flourish across Britain in the 19th century, our kindred artists depicted real local landscapes rather than imagined classical ideals and raised watercolour from a sketching medium into a prized art form in its own right.

In a time of trouble, amid terrible hardship during and after the Napoleonic Wars, the Norwich School artists perceived a paradise on our doorstep and their celebratory images of city and county continued even though not a single one of them was able to live on sales of pictures alone.

The Colman Bequest included many works bequeathed by the donor's father, Jeremiah James Colman – Liberal MP for Norwich, industrialist and pioneer of the Eastern Daily Press.

And the gift added a provision for two specially designed galleries to house Norwich School pictures at the Castle which were opened by the then Princess Elizabeth, on June 18 1951, as part of the Festival of Britain.

Although there was a cosmetic updating of the Colman Galleries during Norwich Castle's overhaul of 2001 – a backdrop of damask wallpaper giving way to a sea of creamy white magnolia paint - essentially the presentation was unchanged in six decades. High time for a revisit and a rehang.

The transformation of the galleries, culminating in today's public opening, has been three years in the planning and achieved at a cost of around �100,000.

Principal donors have been the Colman family – with Sir Timothy and his son James Colman (the latter an artist in his own right, with a solo show now running at the 18/21 gallery in Norwich) taking a close interest in all aspects of the scheme.

The redesign was kick-started with �25,000 earmarked by the Castle's former Keeper of Art, Andrew Moore, from the Great British Art Debate partnership with the Tate, and museums in Sheffield and Newcastle.

The East Anglia Art Foundation then raised �20,000 from its members, with further support added from the Heritage Lottery Fund, the John Jarrold Trust, the King of Hearts Trust, Mandell's Gallery and the Friends of Norwich Museums.

For those like me who dislike lately trendy revamps which leave lots of empty space and less stuff to look at, the good news is that more pictures than ever before are now on view.

The majority of the Castle's gems are on permanent display, and long-term loans from the Tate Gallery, including a Turner seascape for context and comparison, are headed by what may well be John Crome's greatest picture – The Poringland Oak. Its return to Norfolk would alone justify this project.

One British Masters gallery is now devoted to the stellar works of Cotman and Crome while the second – The Norfolk Landscape – shows the rest of the Norwich School painters.

Ease of access is emphasised from the outset with the replacement of the old heavy doors from the Rotunda with lighter, disabled-friendly plain glass doors.

Lighting has been vastly improved, and the visibility of many of the featured scenes further enhanced with non-reflective glass and a denser and more varied arrangement.

Now more information is shared via touch-screen computers and more legible captions, titles and quotes. New seating encourages visitors to linger and savour.

Happily the emphasis remains very much on the pictures, but there are interesting introductory films at the entrance to each gallery comparing a changing selection of paintings with contemporary Norfolk views,

The ongoing importance of landscape depiction will be shown through a changing exhibition of works by contemporary artists — the launch show, The View From Here (running to November 18), comprising recent photographs by Mark Edwards.

Placing a camera on a large tripod, and himself on a step-ladder, he echoes the practice of early photographers in a time-consuming process which makes for thoughtful and tranquil images.

He chooses to focus on neglected corners of our landscape - at Caistor St Edmund, Poringland and Hursley Hill - where wildness remains amid barbed wire and telegraph poles and tracks of vast vanished creatures.

And the strangely elegiac Edwards view entitled River, Bungay could be a subject for a Cotman sketching party until we look more closely and spy the bright and very modern blight of plastic bottles and tin cans among the reeds and water weeds.

Talking of colour, the walls have been painted in complementary hues - hurrah for Farrow and Ball.

So all is light and lightness of touch — just like the genius of the Norwich School.

? Castle Museum and Art Gallery is open daily from 10am-4.30pm (Sun 1pm-4.30pm), �6.80 (�5.80 cons), �4.90 children, Pop in for �1 one hour before closing time and 12pm-1pm weekdays during school term.

? There is a programme of special events for Re-imagined: The Norwich School of Artists, including a talk by curator Dr Giorgia Bottinelli on June 18. For more information call 01603 493625 or visit: www.museums.norfolk.gov.uk