SOUTH QUEENSFERRY, SCOTLAND.- In recent years, the market for Scottish art has seen almost unparalleled growth: last year, Sotheby's sales of Scottish paintings at Hopetoun and Gleneagles made a record total of £8.6 million (compared with £4 million in 2003). Although the headlines may have been dominated by prices such as the £744,800 paid for Jack Vettriano's Singing Butler (Sotheby's, Hopetoun House, April 2004), demand has also increased for a wide range of late 19th- and 20th- century Scottish artists, ranging from the Glasgow Boys, through to the Colourists, and to more recent artists such as Anne Redpath, Elizabeth Blackadder, Philip Howson, and Alberto and Leon Morrocco. In the light of this, Sotheby's forthcoming sale of Scottish Paintings, to be held at Hopetoun House, near Edinburgh, on Monday, April 18, 2005 is set to be an exciting event.

Samuel John Peploe was a key figure in the Colourist movement, and so the emergence onto the market of two important works - one a newly-discovered work, the other one of the artist's finest still lifes - is significant.

Peploe spent his entire career striving to create the perfect picture, obsessively working and reworking compositions, and lingering over the display at his local greengrocer's in search of the "perfect" orange or lemon to include in his composition. However elusive "perfection" may have seemed to the artist himself, critics concur that his works of the 1920s came closest to achieving this holy grail. It is somewhat surprising, then, that one of the artist's most accomplished works, executed at exactly that "golden moment", should have languished for so long in obscurity.

Painted circa 1925, Still Life with Pink Roses and Oranges ranks among Peploe's finest works, and yet this major painting - totally unrecorded in the literature on the artist - has only ever been seen in public once before. Purchased by the ancestors of the present owner at Peploe's first American exhibition, Still Life with Pink Roses has remained in the same family ever since. After so long in the shadows, its appearance on the market in April is set to generate enormous excitement.

Having recently emerged from even greater obscurity, a second work by Peploe is set to cause similar excitement. Discovered in the course of a routine valuation in America, this second painting had hung in the same home - unremarked by successive generations of the family - for many years. It was only in 2004, when Jonathan Greenberg, an expert from Sotheby's New York, was invited to value various other items in the house, that the process of identifying this important, but unsigned work began. Recognising the painting as a work of quality, Jonathan removed the Still Life from the wall in order to inspect it more closely. To his, and the family's surprise, on the reverse was a touching portrait of a young girl. Intrigued, he sent photographs to André Zlattinger, Head of Scottish Paintings at Sotheby's in London. André immediately recognised Peploe's hand, and so it was that these two intriguing images were at last restored to their rightful place in Peploe's known oeuvre.

While the two subjects - both unrecorded - represent important additions to Peploe's known work, a question mark remains over the identity of the young girl on the verso. It has been suggested that she may be the painter's niece, Margery Porter, or even that she may be the charming Peggie MacRae, a much-admired model whose services were highly sought-after by contemporary artists at the time. Whatever her identity, it is clear that Peploe held her in great affection, and his remarkably tender treatment of what is for him a rare subject (he seldom painted portraits) marks this out as an unusual and fascinating example of the artist's work (est: £50,000-£70,000).

Another key figure in the colourist movement, George Leslie Hunter was also much appreciated in America in his day. Hunter, in fact, spent his formative years in San Francisco where, coincidentally, his dazzling view of Cassis (est: £30,000-£40,000) has recently been discovered. The other important work by Hunter in the sale is as still life of Anemones and Citrus Fruit, a work dealing from the early 1920s when the artist's still lifes were at their most brilliant. It is consigned by the descendents of Professor James Hendry, one of the most important early collectors of colourist works.

In addition to Hunter, the other two leading figures in the Colourist movement were Francis Campbell Boileau Cadell and John Duncan Fergusson, both of whom are well represented in the sale. Among nine works by Cadell are three exceptional renderings of the artist's favourite painting ground: the islands of Mull (Loch Don, Mull, est: £25,000-£35,000) and Iona (The Bather at Iona, est: £50,000-£70,000) and Iona, est: £20,000-£30,000).

Meanwhile, two works by Fergusson demonstrate his fascination with organic natural forms and themes of fertility. The first, a Still Life of Roses (est: £60,000-£80,000), is full of the suggestive rhythm of feminine contours. These are rather more apparent in one of the artist's last works, Magnolia, La Baigneuse, of 1958 (est: £40,000-£60,000). The work depicts a beautiful girl who Fergusson (known for his love of women) spotted on the beach in at Antibes. Knowing he could not approach her directly, Fergusson persuaded his remarkably forgiving wife to make overtures on his behalf. The trusting beauty agreed to pose for the artist and this highly sensual nude is the result.

Subsequent generations of Scottish artists are also fully represented in the sale, with sections devoted to the Edinburgh Group (Anne Redpath, Sir William MacTaggart, Sir William Gillies, and Anne Redpath, whose Still Life with Pink Lilies and a Blue Tablecloth, est: £40,000-£60,000), Post War Art (William Geer, Elizabeth Violet Blackadder, Robin Philipson), father and son Alberto and Leon Morrocco, the New Glasgow Boys (Stephen Campbell, Ken Currie and Philip Howson, whose Age of the Apathy sold for a record £64,800 at Sotheby's, Gleneagles, last year.)

Finally, of course, the sale includes 20 works by the artist whose astonishing success in recent years has been the subject of so much attention: Jack Vettriano. The works span the artist's entire career, cataloguing his enduring fascination with intimate moments in male/female relationships. Among them are Bert's Favourite Girl (£10,000-£15,000), The Red Room (£100,000-£150,000), Dressing to Kill (£100,000-£150,000), The Same Old Game (£120,000-£180,000), and a preparatory study for one of his most celebrated works - Billy Boys, (est: £50,000-£70,000).