There was a time, back in the eons that preceded "modern" art, when buildings, sacred and profane, demanded decorative embellishment -- sculpture, altarpieces, friezes, murals, tapestries and, later, wallpaper and Tiffany lamps. Bernini's baldacchino in St. Peter's in Rome, after all, was conceived as interior decoration; so was the Sistine Ceiling.

But with 20th-century "modern" architecture came the big purge, and form doggedly followed function, leaving no room for the frivolities of embellishment. "Decorative art," for the first time in history, became a perjorative term, and a wall was thrown up between "artists" and "craftsmen." The word "art," meanwhile, lost its meaning as a qualitative term. It came to refer, for some obscure reason, to those objects made from paint and canvas (high art), as opposed to those made from clay, fiber and glass (low art). Craftsmen sought to break down the barrier by insisting that they be called "ceramic artists" or "fiber artists," but if titles changed, attitudes did not.

A new show at McIntosh/Drysdale Gallery, entitled "The Decorative Image," now suggests that these barriers may be tumbling at last, due not to the efforst of craftsmen, but to those of several painters. In 1974, these painters sought relief from the barren landscape of minimalism by turning to the opulent colors, textures and patternings of decorative art as their sole subject matter, just as the "pop" artists turned to the comic strip. Miriam Schapiro and Joyce Kozloff, along with "pattern-painters" Valerie Jaudon and Jerry Clapsaddle, represent but two of several '70s tendencies, that now seem to be converging into a fullfledged post-modern decorative trend. t

Matisse, of course, expoused the "merely decorative," as has Frank Stella in his curvaceous new wall reliefs. But the 18 artists in this show are making more aggresive statements. Schapiro, for example, perceived sexism in the belittling of works made with needle and thread, and thus her new fan-shaped canvases, collaged with cloth, ribbon, glitter and beads, are decorative celebrations and feminist overtones.

Similar in intent though more complex is the "Oakland Cookie Cutter Wainscott" built by Joyce Kozloff and constructed from hand-decorated clary tiles made with cookie cutters. Kozloff is simultaneously chopping away at the notion that "craft" is functional and that "art" is not. To make her point, she has produced a work of art that she insists must be used.

The notion of functional art is also at the heart of several other works in this show, including Jane Kaufman's tour de force of crochet -- a web of gold filament meant to be used as a window screen. Former stage designer Robert Kushner's painted fabric swath is meant to hand over an arched doorway -- in other words to "function" as pure decoration. More painterly -- and most beautiful as works of art -- are the pattern-paintings of Jerry Clapsaddle and Valerie Jaudon, whose elegant canvases are covered with linear interlacings that quote from Moorish architecture.

There is much more: works by Brad David that are takeoffs on decorative art; the sewn-together, banner-like hangings of Kim McConnel; and the tacky constructions from "found" objects by Thomas Lanigan Schmidt. But, it is Joe Zucker's work, "Mendel's Garden," that sums up the show. Though made of paint and rhoplex on canvas, it reads as a textured tile wall. As inMendel's botanical experiments, crossbreeding of art if its various forms is what Zucker's work is all about. The exhibition at 406 7th St. NW continues through April 2.

If is sheer coincidence that American folk art and antiques currently are being featured at the Angus Whyte Gallery, also at 406 7th St. NW, but the show reinforces the notion that decorative arts are making deep inroads into the world of high art. Whyte has loaned his space, through April 9, for a display of current stock from the new antiques dealership of John Newcomer and Teddy Westreich, and it is refreshing to see this array of quilts, carvings, weathervanes, samplers and other high-quality items in a pristine gallery setting. Prices range from $15 for an early pincushion to $19,500 for a 1798 dower chest painted by Johannes Spitler.

Photo-realists often specialize, so far as subject matter is concerned: Ralph Goings in cars, Chuck Close in faces, and Richard Estes in glistening glass storefronts and window displays. Robert Cottingham, now showing at Fendrick Gallery, 3059 M. St. NS, is best known for his sub-speciality, the American signscape: the neon and painted lettering from the '40s and '50s that still adorns the facades of old downtown American (or what's left of it) and the seedy bars, restaurants, tatoo parlors and movie marquees now swiftly disappearing from the urban landscape.

in this Cottingham's first Washington show, several new paintings, drawings and prints take a characteristically sharp, up-angled look at several such sign-laden facades, and make clear, for one thing, that Cottingham's art has considerably more to it than mere documentation. A photo-realist begins with his own color slides, then distills the image he wants to paint by first making a black-and-white drawing, and then a color painting on paper, which he subsequently projects and draws upon his canvas before completing his work.

But two things happen in the proccess: The image is compacted into an intense, complex and somethimes disorienting composition; and the color is transformed into something almost magical at times, as in the beautiful blue of the storefront and awning in a painting entitled "Candy," or the delicate, unearthly pink-red neon of the movie marquee in "Black Girl." "Cafe-Bar," the largest painting in this show, also demonstrates how Cottingham locks his three-dimensional images into a surface pattern that sustains interest for considerably longer than one might expect. The show continues through March 31.