According to the artist David Hockney, no slouch in the field of watercolour painting, traditional drawing should lie at the heart of all art.

"Even on the computer," the 77-year-old said in a recent interview, "it's always back to the drawing board."

In this year's Royal Scottish Society of Painters in Watercolour (RSW) winter exhibition, which opens on Friday in the upper floor of Edinburgh's Royal Scottish Academy (RSA) building, the act of drawing is placed firmly in the spotlight.

The man charged with coordinating this annual celebration of the best of Scottish watercolour painting is RSW President, John Inglis, who has a number of works on show, including a beautifully stark drawing called Portal and one of his sketch books. It's fascinating to see how Inglis's representational drawings veer off into abstract landscapes in finished watercolours, Barnhouse, Orkney - Summer and Disturbed Cairns, Orkney.

Inglis and the organising committee behind the exhibition felt since the RSW was occupying the entire top floor of the RSA building (in previous years it has had to share with the fellow artist bodies, The Society of Scottish Artists and Visual Arts Scotland), they wanted to "give the show a slightly different feel".

"By including drawing, sketch books and artists' books," he says. "We are attempting to illustrate the importance of drawing in the creation of the more finished watercolour pieces, giving a little insight into the thinking processes that take place in researching themes and the different ways that developments take place and are represented. A good number of our members responded to the call for sketchbooks."

I always find it fascinating to peek inside an artist's sketchbook. It's like gazing into their mind and catching the trials and errors which go towards making a finished piece of art. Many artists are shy about showing these intimate documents to strangers, so this chance to see sketchbooks by the likes of June Carey, Gregor Smith, Marj Bond, Marian Leven and Sandy Murphy is to be seized with pleasure as well as curiosity.

The core of any RSW exhibition is watercolour painting, and this year there is a wide sweep in the form of more than 400 individual artworks from members of the society, including Prince Charles (its Royal Patron), non-members and invited artists.

This year, the RSW brings to Scotland a selection of works by watercolour artists from China and from the Fabriano Watercolour 2014 International Prize, including artists from Italy, Spain, Belgium and UK. Many artists will receive a jolt of recognition at seeing Tejo Van Den Broeck's painting of a spaced-out man, presumably the artist himself, bound up in what seems like bubble-wrap... ready for dispatch!

The Society has invited a watercolour installation by acclaimed Scottish artist Kate Whiteford, whose work on paper is seldom seen in her homeland in a gallery setting. She is perhaps better known for her land drawings at Calton Hill in Edinburgh and at Eden Court Theatre in Inverness, to name just two.

Other invited artists are veteran abstract expressionist painter, Albert Irvin, whose vivid works will add a dash of va-va-voom to the dark days of January, and Zarah Hussain, whose beautifully precise patterned paintings are informed by the natural beauty of the universe in all its forms.

Another plus-point of the society having more space to play with this year is the return of a carefully selected body of work by recently graduated students from Glasgow School of Art, Edinburgh College of Art, Gray's School of Art in Aberdeen and Duncan of Jordanstone in Dundee.

Added into this heady mix is a selection of watercolour paintings by recently departed greats who also happened to be RSW members. There are four paintings by Alan Davie, who died last year at the age of 93, and one by Derek Clarke, who passed away in February last year. Though his long teaching career at Edinburgh College of Art, Clarke influenced many of the artists whose work is on show here, including the late John Bellany. There is a cracking Bellany self-portrait on display.

All of the work on show - including the Bellany selfie - is for sale.

Royal Scottish Society of Painters In Watercolour: 134th Winter Annual Exhibition, Upper Galleries, RSA Building, The Mound, Edinburgh (, January 16-31