For almost 70 years, Andrew Wyeth worked in a converted country schoolhouse in Chadds Ford, Pa. Now the studio of one of the most revered American painters is open for public viewing.

For most of the 20th century, almost no one saw the inside of that room.

It's a very modest room, about 350 square feet with north-facing windows. The walls are a patchwork of plaster and touch-up paint. The ceiling is cracked and flaking. The place is kind of a mess.

"You see sketches, studies, quick watercolor washes all over the floor. Some hanging on the wall here," said Mary Nell Ferry, a tour guide. "Watercolor allowed Andrew Wyeth to capture his quick thoughts. It's not the fine detail that you're used to, it's the looser side of him."

There are broken egg shells (Wyeth mostly worked in egg tempera), photographs are haphazardly hung on the walls, and sketches are scattered on the floor. Ferry said Wyeth enjoyed seeing his preliminary sketches scuffed with footprints and paw prints.

Andrew Wyeth and his wife, Betsy, moved into the former schoolhouse in 1940. They moved out 20 years later, but Wyeth continued to use it as a studio until his death in 2009. It's there he painted the somber, pastoral, and tautly emotional work for which he is known.

For a few years in the 1960s, he shared the house with his son, Jamie, who used a tiny, partitioned corner of the living room as a makeshift studio. In that humble corner the young Wyeth created the official posthumous portrait of President John F. Kennedy and the countercultural "Draft Age."

Father and son, apparently, fought over the hi-fi.

After Andrew Wyeth's death, his widow donated the studio to the Brandywine River Museum, an institution devoted to the artistic dynasty of the Wyeth family.

Curators re-created the interior of the house based on memories of family and friends. In a video interview, Jamie Wyeth recalls that this father would fling paint around wildly.

"You'd think it would be pristine, painting with one little hair brush," said George "Frolic" Weymouth, one of Wyeth's oldest friends. "He had bravado with his watercolors."

Outside the studio, the rest of the house is neatly and precisely laid out. The library is stuffed with art books (Eakins, Dürer, Homer) and copies of favorite films in 16mm reels, including "Captain Blood" and "Big Parade," a film he is said to have seen at least 200 times.

The walls were washed in off-white, the oak floorboards have grayed with age. It is furnished with simple, wooden tables and chairs and a large, heavy wardrobe.

Friends were welcome in the house, but nobody was allowed in the studio.

"He was a very, very private person," said Weymouth. "You want total privacy when you're building a picture. Many times, his wife didn't even go in unless he asked her to criticize something. It was totally his world right there."

The Brandywine River Museum is now offering limited tours of Wyeth's studio, packaged as a one-day "immersion" experience, including the N.C. Wyeth studio and the Kuerner Farm. Regular, daily tours will be offered beginning July 3.