November 27, 1986

The day the original fabric designs of the Wiener Werkstatte were rediscovered is woven into Peter Backhausen's memory. The sinuous geometrics of Josef Hoffmann, the fanciful floral patterns of Koloman Moser were lying untouched until the mid-1970's in an old wooden cupboard in an empty office building on the Kaiserstrasse, the place that had once housed the drawing department of Johann Backhausen & Sohne. ''It was like God saved them for us,'' Mr. Backhausen says. That the designs had survived at all was a miracle. Destroyed during World War II were the mills and showroom of Backhausen. This was the family-run company founded in 1849 that produced the original textiles for the Wiener Werkstatte, the Viennese design collaborative founded by Hoffmann and Koloman Moser in 1903. The fate of 3,000 original drawings and sketches of the Wiener Werkstatte was unknown until Mr. Backhausen's discovery. Before then there hadn't been much impetus for rescuing them. After the war and until recently ''these design ideas were forgotten,'' says Mr. Backhausen. Today the Wiener Werkstatte style flourishes with renewed appreciation in everything from the highly acclaimed ''Vienna 1900: Architecture and Design'' exhibition at the Museum of Modern Art to carpets at Barneys New York Women's Store.

When the children of the Shinnecock Indian Reservation of Southampton, L.I., talk of their ''two Thanksgivings,'' it is clear which one holds greater significance for them. Last Thursday was Indian Thanksgiving, as it is known. At that time 400 tribal members and guests gathered at the community center for a feast of turkey, succotash and other native foods. The elders spoke, the children sang and beat goatskin drums, and a 10-year-old girl boasted of tea her mother had brewed.

In what many analysts called the first solid evidence of a turnaround in the trade deficit, the Commerce Department reported today that a surge in exports narrowed the deficit last month to its lowest level since August 1985. The trade gap - the amount by which imports exceed exports - fell $500 million, to $12.06 billion. Administration officials and private analysts said they were particularly encouraged by a 10.3 percent rise in exports, the biggest in 19 months, which more than offset a 4.4 percent rise in imports. Economist Is 'Encouraged' ''What we're seeing is the first really serious sign of improvement in exports,'' said Keith N. Johnson, senior economist at Townsend-Greenspan Inc., a New York consulting concern. He said he was considerably ''encouraged'' by today's report, which was markedly better than most forecasters had expected despite a widening of the trade deficit with Japan.

Barnes & Noble, the nation's leading book discounter and its third-biggest bookseller, has purchased B. Dalton, the nation's second-largest chain of bookstores, which has been faltering lately because of competition from discounters. Neither the Dayton Hudson Corporation, the parent of B. Dalton, nor Leonard Riggio, owner of Barnes & Noble, would disclose the sale price for the 779-store chain. Analysts, however, estimated the price at between $275 million and $300 million. Mr. Riggio, whose 35 Barnes & Noble stores are situated mostly in the New York City area, said that he would continue to operate the two chains independently, under their current names. Barnes & Noble's flagship store is at 6 East 18th Street, on Fifth Avenue. Its well-known Sale Annex is across the street.

Americans over 50 make up about a quarter of the population, but account for roughly half of the nation's discretionary spending and more than three-quarters of its wealth. And their numbers are growing. Small wonder, then, that companies are increasingly wooing older consumers. But while some - especially those involved in travel and health care - have marketed effectively to older consumers for many years, many others have not been so lucky. In fact, the more corporate America courts this business, the more it discovers what a tricky business it is. Consider, for example, Johnson & Johnson's Affinity shampoo, a product it promoted as beneficial for brittle, hollowed-out, older hair. The shampoo flopped, until references to older hair were deleted. Alberto-Culver ran into similar problems with its Prime Time shampoo, also meant for older consumers. The company has since decided to steer clear of that market ''because we haven't been able to come up with a good marketing approach,'' said James O'Connor, a spokesman.