FOR more than 60 years, it has hung out of sight in a private Glasgow collection – a strange and sinister work by the Scottish Colourist FCB Cadell, which has never before been shown in public.

But now, thanks to an appeal from the National Galleries of Scotland (NGS) in The Herald, one of Cadell’s most unusual works is part of a major exhibition in Edinburgh.

The Edge of the Wood was bought by a Glasgow collector in the 1950s and has remained out of public view since then, but the owner -- who wishes to remain anonymous -- saw an appeal by the NGS for Cadell works for the show and offered the work for the nation to admire at last.

The work, dominated by a tree with a sinister shadow that could be the shape of a man or creature, may have been painted in the late 1920s, when mounting debts and health problems beset the Edinburgh-born artist, who is perhaps best known for his paintings of elegant interiors, still lifes, and the beaches of Iona.

The Edge of the Wood appears in a show, opening on Saturday at the Scottish National Gallery of Modern Art, which is the first Cadell retrospective to be held at a public gallery since a memorial exhibition in 1942.

Alice Strang, senior curator at the galleries, said the work deserves to be in a show of the “80 best paintings he ever made”.

She added: “There is this idea that Cadell’s fortunes slowly and gradually declined, and some people have looked at this painting here and seen it as sober, almost sinister, and perhaps it reflects his state of mind.

“You feel like a very different artist painted this compared to Kelvingrove’s Orange Blind, for example.”

Ms Strang said the galleries had a very positive response from the original story in The Herald, which ran on December 31, 2010.

“Cadell died in 1937, so it is not too long [ago] for paintings to remain in the families of the patrons who bought them in the first place, so we thought we would do a call for pictures in The Herald,” Ms Strang said.

“We got quite a lot of response, quite a lot of paintings were considered, but this ended up being the one.

“We believe it to be the latest painting in the exhibition, and it is so unusual.

“Cadell was known for his elegant interiors, his elegant women in interiors and still-lifes, but this is a wooded landscape, quite sinister in feel, and in quite a different palette, very autumnal.”

Ms Strang said the painting could be of woods at Auchnacraig, near Dirvaig on Mull, in 1927, and may have been influenced by the kind of landscapes that another colourist, SJ Peploe, was also painting at that time.

“It is definitely an unusual Cadell, and interesting because of that,” she said.

“I think we can comfortably say it is the first time it has been seen in public for at least 50 years, if ever. The owners love it, and are intrigued by it because it is unusual.”

Francis Campbell Boileau Cadell, who lived from 1883 to 1937, is one of the four artists known as Scottish Colourists. He lived in Edinburgh for most of his life, and studied in Paris and Munich.

Cadell was the youngest of the Scottish Colourists and was the only one to fight in the First World War.

Like his fellow Colourists -- Peploe, JD Fergusson and GL Hunter -- Cadell’s works sell for high prices at auction. Last year a record was set by the sale of his Florian’s Cafe, Venice, at Sotherby’s for more than £550,000.

Ms Strang said it was apt that it was through The Herald that The Edge of the Wood had been discovered. In 1923, the then Glasgow Herald reviewed the landmark exhibition at the Leicester Galleries in London of the work of Cadell, Peploe and Hunter, the first time the three were shown together, and was unusual in praising Cadell’s work, which confounded many critics at the time.

The galleries are also to hold exhibitions of SJ Peploe in October next year, and JD Fergusson in 2013.

The Cadell exhibition, entitled The Scottish Colourist Series: FCB Cadell, runs from October 22 to March 18, next year.