If the "Antiques Roadshow" returned to Pittsburgh, it likely would draw an unexpected treasure cache of paintings by a relatively little-known group of Western Pennsylvania artists who are fast becoming hot.

People who are fond of landscape painting, Americana and the nation's cultural history know about the Hudson River School, a circle of 19th-century artists loosely associated through the sites they painted (the Hudson River Valley and New England in particular) and even more so by the transcendent attributes they ascribed to nature and especially wilderness.

Far fewer know of the Scalp Level School, artists who gathered annually to paint the deep hemlock glades and rock-studded streams of the Appalachians near Johnstown and named for a borough in Cambria County. But that's changing rapidly, due in no small part to the interest shown by the Westmoreland Museum of American Art, Greensburg, which launches its 50th anniversary year next Sunday with the exhibition "Scenic Views: Painters of the Scalp Level School Revisited."

The exhibition comprises 69 paintings by 23 artists, five of whom are women -- somewhat surprising given the time period (Andrew Carnegie's mother was among the chaperones who accompanied the mixed-gender sketching trips).

The best known are George Hetzel (1826-99), considered the school's leader; William Coventry Wall (1810-86), self-taught and the oldest artist to travel to Scalp Level to paint; and Albert Francis King (1854-1945), the Scalp Level artist most identified with still lifes.

The paintings span the years 1840 to 1910 and include, besides the signature Scalp Level woodland interiors, landscapes as far afield as Magnolia Beach, Mass., and

Niagara Falls (a Hudson River School mecca), as well as still life and genre scenes.

It's telling that none of the paintings has been publicly exhibited before and that of 22 lenders, 20 are private collectors, some living as far away as Washington, D.C., but the majority within Western Pennsylvania. Carnegie Museum of Art and the Philip and Muriel Berman Museum of Art at Ursinus College are also lending paintings, and the Westmoreland will debut two works from its collection.

Much of the reason for the discrepancy between Hudson River and Scalp Level artist reputations can be attributed to marketing, says Westmoreland director and chief executive officer Judith Hansen O'Toole, who is also exhibition curator.

Hudson River artists, living and working in and near New York City, were "where the dealers were, where the museums were built, where there was a more international society, where the critics were who would write about their work," O'Toole says. "That infrastructure came together to make them the national school."

But Scalp Level painters shared the 19th-century landscape aesthetic of the Hudson River artists and could find all of the "important defining themes ... man vs. nature, the cyclic quality of days and seasons, the awesome power of nature in changing weather and seasons, and the simpler, beautiful aspects of flora and fauna" in Western Pennsylvania.

Pittsburgh-based Hetzel, who made his first summer sketching trip to Scalp Level in 1866 and returned almost annually for three decades, sensed the disadvantage of living outside that East Coast community and even tried to establish himself by moving to Philadelphia. But he returned after one year, in 1870.

Chastising local collectors for having eyes only for prestigious European artists as a way to impress friends, Hetzel told The Pittsburgh Dispatch on Dec. 20, 1896, "My regret is that I located in Pittsburgh. I would have been more successful if I had gone elsewhere. If I had my life to live over and had the experience I have now, I would not have stopped in this city."

The fortunes have improved for Scalp Level painters as a young field of American art historians turns from the extensively documented Hudson River School to artists who painted in other parts of the country and to institutions such as the Westmoreland, which had the foresight to collect their works.

The exhibition is dedicated to the memory of the Westmoreland's founding director, Paul A. Chew, who, O'Toole says, "had the vision to say we should collect what's in our region."

Chew supported research and publishing that would make regional artists better known and ensure that their legacy didn't disappear. He published volumes on southwestern Pennsylvania artists in 1981 and 1989 and on Hetzel in 1994. Chew "determined the direction of this institution, which would be primarily American art, secondly Pennsylvania art, and thirdly the artists and images of Western Pennsylvania," O'Toole says.

Continuing that mission, O'Toole is writing a comprehensive book about the Scalp Level painters projected for publication in 2009-10.

One aim of the exhibition is to bring to light lesser-known artists, or those like John W. Beatty who is known as the first director of Carnegie Museum of Art but not for his Scalp Level association.

Another aim is to attract scholars to the Westmoreland, and to that end the museum is actively seeking Scalp Level documentation, archival materials, sketchbooks and artworks.

"Our goal in our acquisitions is to have great depth within this school -- both great pictures and sketches. For focus on the subject and accessibility of information, the Westmoreland has emerged as the place to come to," O'Toole says.

The recent increased awareness of the Scalp Level School is a double-edged sword for the museum.

Paintings that have been in artist and collector families for decades are entering the national market and a number of New York and Philadelphia galleries are seeking out works by King, Hetzel and Wall, O'Toole says.

As better-researched and better-published artists rise out of a moderate price range, the art market looks for the next tier, she notes, and the Scalp Level climate is beginning to resemble the late 1960s and early 1970s revival of art market interest in the Hudson River School.

This heightened interest brings welcome attention and value to the Westmoreland collection, O'Toole says, "but the prices are double, triple, what they were 10 years ago," which makes expanding that collection all the more difficult.