Chester and Davida Herwitz have been collecting contemporary Indian art for more than 20 years, often spending as much as six weeks a year in India. A show of 59 works, "Indian Art Today: Four Artists From the Chester and Davida Herwitz Family Collection," opened Saturday at the Phillips Collection.

The show is the product of one Worcester, Mass., couple's fascination with, and love for, the art of a country that was one of many they visited on a trip around the world in 1962. The Herwitzes saw contemporary Indian art featured in the National Gallery of Modern Art in New Delhi and were "enthralled." At that time, India lacked "an extensive gallery system," says Chester Herwitz.There were "one or two galleries in two or three major cities . . . It was almost impossible to see contemporary art."

So on their own, the Herwitzes sought out artists like Sayed Haider Raza and Maqbool Fida Husain, whose "energy and vitality and . . . fluid forms" they enjoy. Husain, who started out as a billboard painter, was a founding member of the Progressive Artists' Group, formed in the late 1950s by artists who were protesting the British-founded Bombay Art Society and struggling to create a national artistic style. "When the British left India they left it in bad shape with regard to artists," says Chester Herwitz. "Raza and Husain knew that they had to go back to their roots to find their own artistic language."

Herwitz will not say how many pieces he owns; he prefers to say that the couple collects "in depth." "As a collector, I have never been interested in collecting the best work of an artist," he says. "If I come to the conclusion that this artist's vision means something to me, as long as I see points of departure, and a continuing connection, then I am still interested."

The Herwitzes are going on to Paris, where part of their collection is being shown at a contemporary Indian art exhibit at the Georges Pompidou Centre. The collection at the Phillips is on display through April 6. Revisiting 'Brideshead'

Rapture spread quickly among Washington's Anglophiles, art lovers and just plain "Treasure Houses of Britain" fanatics last week after National Gallery of Art Director J. Carter Brown announced that the gallery would extend its popular exhibit through April 13. The exhibit originally was scheduled to close March 16. At the same time, Brown and Granada Television, a British outfit, announced that they will sponsor free, lunch-hour screenings of "Brideshead Revisited," beginning April 1 and continuing for 11 days in the East Building auditorium. Weekday screenings will be at noon, weekend screenings at 6 p.m.

"Brideshead" was largely filmed at the Vanbrugh-designed Castle Howard in Yorkshire; it is considered to be the model for Evelyn Waugh's Brideshead Castle. Two paintings are among the Castle Howard items in the "Treasure Houses" show. Look for Guercino's 1649-50 "Erminia Finding the Wounded Tancred" and Sir Joshua Reynolds' "Frederick Howard, 5th Earl of Carlisle." Or, if you can't find them on your own, just call the National Gallery. There is a recorded message for the exhibit (842-6672), but a human will answer the phone if you call 842-6690. Calvert's Chamber Concerts

It's not a bad idea: An area chamber group plays a series of evening concerts in an art gallery, and the musicians mingle with the crowd at receptions before and after, discussing their perspectives on the evening's musical program. That idea has taken form at the Calvert Collection, 2301 Calvert St. NW, where the gallery owners have teamed up with the Columbia Players, an area chamber group, to sponsor a series of Monday evening concerts/receptions called "The Music Connection." Next week, the Columbia Players are due to play an often-heard work -- Beethoven's Quintet in E-flat for Piano and Winds, Op. 16 -- as well as a less-often-heard work -- a quartet for flute, violin, horn and cello by Carl Stamitz. Tickets are $10. For reservations, call 534-7272. Odds and Ends

George Mason University will celebrate the works of New York City short story writer Grace Paley with a 7:30 p.m. Wednesday screening of "Enormous Changes at the Last Minute," the 1985 film based on three Paley stories; it stars Kevin Bacon and Ellen Barkin. Paley will read from her work at 8 p.m. Thursday. Both events are free. For information call 323-2221 . . . In honor of notable Virginian Patrick Henry's 250th birthday coming up in May, the Friends of the Patrick Henry Library in Vienna are sponsoring a portrait-painting competition for all Northern Virginia painters. The winning portrait of Patrick Henry will be hung in the library, and the winner will receive $400. Michael Monroe, Renwick Gallery curator, will judge the entries. For an application call 938-6664.