The auction world might be busy preparing for the major fall sales, but there’s one sign that the dog days of summer aren’t over quite yet.

Sotheby’s holds its Scottish & Sporting Pictures sale at the Gleneagles Hotel on August 26. A laid-back, late-summer event, it has been attracting a diverse crowd of art aficionados to the Highlands for four decades. “Buyers nowadays are more receptive to all eras of British painting. It’s a very fun crowd at the Gleneagles,” the head of Scottish Pictures for Sotheby’s, André Zlattinger, said.

What also helps the popularity of this auction is that Scottish schools of painting have gone international. The Glasgow School was a pioneering group of painters who broke away from their salons and infused their landscapes with hints of Impressionism. They helped lay the groundwork for the Scottish Colorists — men such as Samuel John Peploe, Francis Campbell Boileau Cadell, John Duncan Fergusson, and George Leslie Hunter — in the early 20th century. “The colorists spent time in Paris and got to know the techniques of Matisse and Monet. Their paintings have huge appeal to the international set,” Mr. Zlattinger said.

The heir to both schools is Jack Vettriano, the Fife native whose pictures, when reproduced on note cards and posters, outsell those of every other artist in the British market. “The Out of Towners,” an oil-on-canvas beach scene, is estimated at between $93,300 and $130,500. Perhaps the most popular lot in the auction is one of Mr. Vettriano’s retrospective sketches. He completed his oil-on-canvas sketch of “The Singing Butler” in an hour in a masterclass at St. Andrew’s University in 1993. The school — Prince William’s alma mater — will use proceeds from the sale of the painting, estimated at between $27,900 and $37,300, to fund its student charities campaign.

One of the more unusual works of the Colorists is Cadell’s “Still Life, Tulips,” estimated at between $373,500 and $560,000. Cadell was heavily influenced by his friend Peploe, who spent considerable time in Paris familiarizing himself with the works of Cezanne. “The painting is almost atypical of a Scottish colorist in that he is experimenting with abstraction,” said Mr. Zlattinger.

Another Cadell painting, the oil-on-board “Carnations,” is expected to fetch between $224,000 and $336,000 at next week’s sale. Then there’s Anne Estelle Rice’s oil-on-board “The Dancers at the Folies-Bergere,” estimated at between $56,000 and $74,700, which comes from her family’s estate. Rice’s work has become popular with fans of both American and Modern British paintings. She’s often thought of as the female Scottish Colorist not only for her style of painting, but because she was John Duncan Fergusson’s lover. Philadelphia natives may remember her for the murals she painted in Wanamaker’s Department Store in 1908.

Sir John Lavery’s oil-on-canvas work, “My Studio Door, Tangier,” estimated at between $747,400 and $1.12 million, is a vibrant portrait of the artist’s wife, Hazel, surrounded by the couple’s friends at their house in North Africa. Although Lavery painted many house and garden scenes, especially when he visited his resort home in Morocco, he wasn’t the only famous Briton to do so. The color palette and style are reminiscent of another of his countrymen in love with North Africa: Winston Churchill. “It’s pretty clear to me that he must have known Churchill in North Africa,” Mr. Zlattinger said.

Lavery discovered that painting the rich and famous on their estates could be extremely lucrative. Another lot in the auction is his “Mary Borden and Her Family at Bisham Abbey,” estimated at between $560,500 and $934,000, an excellent example of the sort of crowd that commissioned Lavery to paint them. “Here we see the American novelist, Mary Borden, at her beautiful home in Buckinghamshire,” said Mr. Zlattinger.

Borden, who came from a prominent Chicago family not unlike Lavery’s wife, lived in what was for centuries a priory (and later an abbey). In capturing the oak paneling, beamed ceiling, and leaded glass windows of Borden’s parlor, the artist caught the attention of other well-to-do Americans who wanted to be painted amidst their sumptuous belongings. In 1926, on an American tour, Lavery painted the ornate interiors of homes belonging to the family of J.P. Morgan and, one year later, the saloon of The Breakers in Palm Beach.

No lot in the Gleneagles sale better conveys the ancient golfing tradition than John Charles Dollman’s oil-on-canvas “Lord Rosebury, Admiral Fleming, The Duke of Buccleuch, and Lord Charles Hope with their Respective Caddies at North Berwick,” estimated at between $186,800 and $280,200. “Lord Rosebury was one of the more notable gents from that period,” Mr. Zlattinger said. “The painting really captures what it was like to play golf in those days.”

In the 1840s, golfers didn’t mark their balls on the putting green. Dollman’s painting shows the four distinguished men fretting over what was known as a “stymie,” a situation where one ball directly blocked another from the hole. (Modern rules of golf ban the stymie, which is considered as giving an unfair advantage to the player whose ball is blocking the hole.) Art collectors who are also avid golfers will appreciate the painting for the fact that the hole depicted in Dollman’s work exists to this day; the course at North Berwick serves as a qualifying course for nearby Muirfield whenever that club hosts the Open Championship.

A summer sale in Scotland wouldn’t be complete without a wide array of landscape paintings. “There will always be a strong demand for the traditional Scottish landscapes,” Mr. Zlattinger said. Among his favorites in the sale is Joseph Farquharson’s oil-on-canvas “When Snow the Pasture Sheets,” estimated at between $280,200 and $373,600. In the late 19th century, the artist’s paintings of snowy landscapes with shepherds and sheep brought him so much renown that he was widely known by the nickname “Frozen Mutton Farquharson.”

jakasie@nysun.com