WATCH ANY Sunday. To look at them in churches all over Washington is to fall in love and never forget them. Glorious amid the mahogany pews, splendid on the church steps, phantasmagoric on the Sunday sidewalks is headgear that is confected and architected into the institutions known in the Black Bible Belt as Christian Lady Hats: tissue-papered yo-yo quilt tams; towers of pink tulle; red straw brims weighed down with white roses; black felts with shovel brims; brocade cloches; effulgences in velour and beaver; velvet prints with feather wheels; rhinestones; veils and lace; rainbows of purple, pink, red and black grosgrain whirled into cones, domes, ziggurats, crowns; turbans, pillboxes and panamas in scarlet, turquoise, peaches and cream. Ah, the feast of creativity.

Sure, lots of women wear hats. Nancy Reagan, Effi Barry. Not to mention Queen Elizabeth II, who appears to have a chapeau for every occasion. On the Grammy Awards broadcast, Grace Jones, musically definitely a hardedged and unchristian lady, almost knocked everyone over with a diaphanous parasol hat.

However, the black Christian lady, be she Pentecostal or AME Zion, not only has a hat, but also has a look that rarely can be imitated.

Often the hat is merely the beginning. The look includes shoulders that act as shelves for fox and mink pieces, and a rhythmical walk, timed by the sway of the hips held high, nature's gift for carrying parcels and children, but on Sundays pendulums of authoritative pride. These women share with all women the search HATS, From K1 for individuality, the peer demand to be fashionable. But they also are motivated by strict propriety that is unwavering among middle-aged women in black churches, along with a need for self-esteem still too often denied by people outside the black community.

In the last decade, the declaration of St. Paul to the Corinthians that women should cover their heads has been increasingly ignored.

But not by these ladies, to whom hats are far more than something to hide the hair.

Delia Perry, an upright Christian Lady, the third generation of her family to attend Evangelical Lutheran Church of Our Redeemer, knows the true value of hats.

"When I moved from an eight-room house to a one-bedroom apartment two years ago, I gave away my crystal, silver, furniture and clothes . . . but I kept my hats," she says. Now, she wears a helmet-shaped black felt, its circular crown creased and decorated with a small black bow. "The last one I gave away was an American-beauty red turban to a friend who helped me move. The other one was two shades of lavender, whirled around like a cone. But I can't tell you how many hats I have; I have boxes and boxes."

She is sitting in her church's fellowship hall. "They don't compete here, but my neighbor and her sister had about 100 hats. They go to the Baptist church, there's more of that there."

Competition. Heads have turned in admiration and astonishment at, say, the red and blue patterned velour with a stovepipe crown and one blue feather. At other times heads have twisted in exasperation, trying to see a preacher obscured by an eruption of crimson tulle.

Friendships have waned at duplications or one-upmanship. "The department stores usually have more than one," says Lucille Hart, a deaconness at Mount Pleasant Baptist Church. "Last Sunday I came here and someone else had my hat on," says Hart, who vowed only to trust her hatmaker henceforth. "Yes, there's competition."

Piles of pecan hat frames; stacks of red-flowered hat boxes; mounds of cloth tea roses; cases of royal irises, emerald mums, velvet burgundy flowers, blue leaves, red feathers, yellow daisies, and white and apricot lilies compose the world of Vanilla Beane, proprietor of Bene' Millinery and Supplies, tucked away far from downtown at 6217 Third St. NW, near Coolidge High School.

She makes and sells hats, but more important, she offers exclusivity, which she says is a high priority among her customers.

She says: "They ask, 'You aren't going to make that again, are you?' "

Out of here tumble red sailor hats, black feather pillboxes, navy shovel brims and white fedoras that have brought her accessory competition prizes and a name that is passed around the Christian Lady circles like the news of a painless dentist.

A member of Gethsemane Baptist Church, she is a short, soft-spoken woman, whose round face seems suited to hats. She gets teased constantly about her real first name and her married name. "People are always calling saying, 'Is there really someone named Vanilla Beane?' "

Here hats are not only institution, art and fashion; they are enterprise. Some Christian Ladies may patronize Bachrach's Millinery and Maison's downtown, but the woman pressured by competition goes to a hatmaker. After 20 years of making hats as a hobby, Beane opened her own professional retail business in January 1982. Those seeking her services cover the age and income spectrum, but most frequently they are young women going to cabarets, and older women going to church functions or social club banquets.

Beane, 63, moved to Washington in 1942 from Wilson, N.C., and worked for the government for 11 years. In 1958 she joined the Washington Millinery Supply Co. as a clerk. The company, once a major source for hatmakers, now specializes in bridal accessories. "I got interested, and just tried to make a round bowl style in a turquoise fabric. And it worked," she says. After formal instruction in the adult evening program at Roosevelt High School, Beane took countless numbers of buckram frames--buckram is the stiff cotton used for hat molds--wet it, molded it and created tams, sailors, panamas, turbans and cloches. The years of dampness and molding have left her with chronically short fingernails, knobby knuckles and stiff fingers. "They look like I have been digging potatoes," she says.

Beane places tenderly on a glass table the first hat she designed as a student--a coffee linen tam with a matching dotted Swiss veil--and a scrapbook of 20 years of designs. Her winning entries in six competitions of the National Association of Fashion Accessory Designers have earned her a place in the trade group's Hall of Fame.

Over the years she has made turbans of gold and black brocade, a velour turban crowned with a feather wheel, sailor styles made of beaver and cloches of velour with a laced-up crown. And all this artistry once cost only about $10.

Now, at prices of $45 and up, Beane offers all the traditional styles, plus the popular shovel, with an elongated frontal brim. She also has what she calls the "fussy ones"--the hallmark of the Christian Lady. "The turned-up brim, the cutaway brim, loaded with flowers and veilings, even with rhinestones," she says. She is kept busy responding to celebrity influence. "The hats on 'Dynasty' were so pretty. And a lady asked me today if she could have something similar to the hats worn by the queen," she says.

It is far, far more than a question of what to wear, however. It is how, it is when, it is why. Hat wearing has its own protocol. Or should, according to Jennie Hall, a minister's widow who now teaches Baptist congregrations protocol and parliamentary procedure.

"When you go to the podium, it isn't proper to be bare-armed, and it is proper to wear something on your head. You should not wear wide hats in the morning services, up until 11 a.m. A tam style is preferable. In the evenings you should wear something sparkling, a smaller hat off your face. They claim you shouldn't wear a wide hat because people can't see around you. At the 11 a.m service you can wear a brim, but not too wide a brim, or a flowered hat in a turban style or narrow brim."

Should one be mindful of the feelings of other churchgoers who might find themselves sitting behind a hat that resembles the Hanging Gardens of Babylon

"Well," says Hall, laughing, "it makes me conscious of what I wear." She adds that it's important not to take offense at complaints. "The best thing to do is move over in the pew."

The rules are flexible, of course. On a recent Sunday, Hall wore a foot-high red turban, accented with a pearl stick pin. Just under five feet tall, Hall prefers the tall styles. "When you're short, you need something to give you height," said Hall, who said she often puts tissue paper in her turban to make it taller. "I used to be fond of the wider hats, which are really back in this year, but after I gained weight . . . you have to be careful with a wide brim."

At Evangelical Lutheran on a recent Sunday, Mildred Nelson Smith is one of 10 parishioners wearing hats, hers being an ivory-colored wide brim with a square crown glistening in the morning sun. She knows precisely why she is wearing it.

"This thing of going to the altar to receive communion without a hat," she says, her tone soft but distinctly disapproving. "Well, I just don't feel dressed."

In the meeting hall of the 10th Street Baptist Church, Geraldine Baultrip and Marie Tucker say it is love and beauty, not law or duty, or even competition, that keeps them going back to the milliner's.

"Hats are very expensive. But I don't mind, if it's what I want," says Baultrip, who sports a sparsely sequined white turban.

Taylor wears a small white cloche with a spray of feathers on the side. She hesitates when asked how long she's had it.

"Well, I borrowed it," she says, glancing at Baultrip, who has lent it to her.

Baultrip laughs. "Oh, you tell everything," she says, adding, "There's no competition here, but there are some beautiful hats."