MOUNT VERNON's first complete redecoration in more than half a century is almost complete. Visitors now can see a Mount Vernon they never knew existed.

The redecoration is the first based on extensive paint analysis and new research into interior architectural history.

According to John Castellani, resident director, Mount Vernon is being returned to 1799, the year Washington died, when he presumably had done the best he could to make a setting suitable to his last great role, the patriarch.

The redecoration of Washington's Mount Vernon estate is part of a major revisionist history of interior design and decoration transforming the major historic houses in the United States and changing the way we view the 18th and early 19th century.

The research at Mount Vernon has shown that many of the ideas commonly held about decoration of that period are not so.

(Thomas Jefferson's Monticello is another house currently undergoing the same sort of rethinking.)

To put it at its simplest: Colors were far brighter, rooms were less cluttered than we had been led to believe, explained Christine Meadows, longtime curator at Mount Vernon.

The result of this redecoration is more drastic than it sounds.

Some of Washington's color choices (as documented by paint restorer Matthew Mosca by microscopic and chemical analysis) will come as a distinct surprise to those accustomed to thinking of the Father of the Country standing against vapid pastel or spoiled-milk white paints.

(See Virginia Devine's story on this page explaining how the paint research was done and how it can be duplicated today.)

Washington liked brilliant greens, blues and yellows -- knock you dead colors. In choosing these paints for Mount Vernon, Washington followed the prevailing Federal fashions. To eyes accustomed to the so-called "Williamsburg Colors" (now being rethought in Williamsburg), the new colors will seem shocking, even garish.

As one expert said, "Back then, paint cost so much, they wanted as much color as they could get."

The 1980 annual report of the Mount Vernon Ladies Association explains why we think as we do about Federal colors:

"Ann Pamela Cunningham, founder and first regent of the Association, would have applauded the new techniques. This pioneer preservationist early recognized the significance of original paint and wallpaper and her modest, unscientific beginnings, about 1869, produced some evidence that remains valid today. Miss Cunningham... fretted over Mansion colors and in the end succumbed to personal taste."

As the Ladies Association points out, the old paint was dirty and faded by the years, not to mention chemical changes -- all these distorted the correct colors.

The plain pine woodwork has been grained, a faux finish, to look like more expensive mahogany and walnut, as it was in 1786. Malcolm Robson, an English graining expert, did the graining on 18 interior doors and frames, the study and central passage paneling for a cost of $18,500.

Even so, to some taste, the study will look spartan, because Washington used neither carpets nor curtains. George Washington added the study (and the second floor master bedroom over it) in 1774, before taking his seat in the Second Continental Congress at Philadelphia and going on to command the Continental Army.

The study wasn't finished until he returned home in 1783. The study has recently been returned to the way it was in his later life, when it was his sanctum. Meadows said he would come downstairs from the bedroom with the king-size bed he shared with Martha, and take his bath and dress in his study so as not to wake her. A portrait of Lawrence Washington (George's elder half-brother), a safe that belonged to Martha's first husband, a terrestrial globe and a revolving desk chair are noted in the 1799 inventory and are among the pieces restored to the study.

(Last year's most important acquisition was a 1757 dressing chest, which Washington owned before he was married, now the earliest piece of furniture in the house.Castellani said the association paid a price "in six figures.")

In 1786 he added the bookpress on the east wall, preserving the wall and floor behind and underneath it, which presumably has not been repainted or replastered since 1786.

The floors, the restorers found, were not usually stained to waxed. Other research has shown that the floors of most 18th-century houses were not stained and eventually whitened from being scrubbed so often.

But redecoration has gone much further than painting.

"Our aim," explained Castellani, "is to show the mansion as it was at the end of Washington's life. We use original furniture when we can, replacing less authentic pieces when possible, but we don't hesitate to use contemporary reproductions to give the effect. For instance, for the birthday we have borrowed the original Peale portrait of Washington and the John Wollaston portraits of Martha Custis Washington and the Custis children from Washington and Lee University. But normally, copies of the paintings hang in the parlor."

In the furniture arrangement, Meadows explained, "we are following the inventory of 1799, compiled at his death."

Twelve pieces of furniture, in the category of "said to be of the period" have been removed from the principal rooms, according to Meadows. "I took a gaming table, a card table and a small stand from the west parlor, six pieces from the Lafayette bedroom and three pieces from the downstairs bedroom."

She added three new chairs to the large dining room, or the banquet hall, bringing the number there to 21. Nine are original to the house, two are of the period, 10 more are 1936 copies from W&J Sloane, originally in Arlington House, the Custis-Lee mansion.

Washington, who held sort of perpetual levees in his house, needed a great number of chairs. At his death, 78 stood downstairs with another 30 lined up on the piazza facing the river, just as though in a resort hotel. Another 25 were upstairs.

In the large dining room, visitors often ask "where's the dining table." The answer, according to Meadows is that there wasn't one. "Trestles and boards were brought in when there was a banquet and removed after the meal."

The space was then cleared for dancing.

Little Hunting Creek Plantation was bought in 1726 from his sister by George Washington's father, Augustine Washington. The land was patented by his grandfather, John, in 1674. Augustine moved his family there in 1735 when George was 3 years old.

Augustine's elder son, named Lawrence, inherited and enlarged the early house in 1743. He renamed it after Admiral Edward Vernon under whom he served in the Caribbean. George, after his father's death, often visited Mount Vernon because he didn't get along with his mother. In 1752, Lawrence died and, after the death of his wife and child, George Washington, to his surprise, inherited the estate, and added to the land until he owned 8,000 acres.

When George Washington moved in the house had a central hall and four small rooms on the first floor and a loft above the hall. When George married, in 1759, he added a full second story and an attic and redecorated. The south and north wings, the study and large 18-foot high dining room were added in 1774.

"With all the research on the house completed in recent years, no evidence has been turned up to show that anyone but George Washington actually designed the finished house," Castellani said. "There is some evidence of influence from the Williamsburg Palace, but not much. His master builder in 1757-1758 was a man named John Patterson, who would have been familiar with designs such as the Palladian window in the dining room, similar to one in Batty Langley's pattern book.

"Washington wanted a formal house," Castellani continued. "He approved of formality, especially among military officers. He appreciated discipline. And so he was very orderly in this house. He wanted it functional and pretty. All we have in his own hand is a simple line drawing of the basement and the entry facade. It's a very unusual house for the period, especially the colonnade and piazza on the river side, so often emulated."

The house is certainly not a palace. The grandest room, the large dining room, is 32 feet long and the parlor is but 18-by-18 feet. But it was a comfortable house and it has become the country's greatest shrine.

The Mount Vernon Ladies Association saved the house in 1858, after both the federal government and the Commonwealth of Virginia had refused it. Today, 250 years after his birth, the memory of George Washington still lives at Mount Vernon.