Monday, Aug. 22, is this year's date for National Film Day, the annual fund-raising event for the American Film Institute. Participating distributors and exhibitors pledge to contribute a portion of the day's gross revenues to support the AFI.

The addition of a new French comedy, "Pardon Mon Affaire," and the slight postponement of an American romantic melodrama, "Outlaw Blues," have increasedto five the number of movies scheduled for Washington area openings on Wednesday, Aug. 17.

"Pardon Mon Affaire" was written by Jean-Loup Dabadie and directed by Yves Robert, who last collaborated on "Salut I'Artiste." Their new film, playing exclusively at the K-B Cerberus 1, stars Jean Rochefort, who stole the earlier one from Marcello Mastoianni, as a blundering philanderer. Victor Lanoux of "Counsin, Cousine" has one of the key supporting roles.

"Outlaw Blues," co-starring Peter Fonda and Susan Saint James as a Country & Western singing act, is slated for 17 area theaters. As previously announced, the other picture arriving on Aug. 17 are "Gizmo" at the Key, "I Never Promised You a Rose Garden" at the Dupont Circle and "Outrageous" at the renovated West End Circle. "Suspiria," an Italian horror melodrama starring young American actress Jessica Harper, who made strong impressions in "Phantom of the Paradise" and "Love and Death" before plunging into "Inserts," one of the more squalid wrongos of the decade, may turn up this Friday, along with Foreign Legion adventure "March or Die."

A three-credit course called "Film and Literature" will be offered this fall at the Rockville campus of Montgomery County's Community College. Dealing with the techniques and problems of adapting works of literature for the screen, the class will meet Thursday afternoons beginnig Sept. 8 and be taught by Gail Forman, associate professor of English.For further information, call (301) 762-6088.

One last screenwriting seminar, the fifth in an ongoing summer series, is scheduled to begin under the tutelage of Sheldon Tromberg on Monday. The numbers to call for detailed information are 966-7799 or 244-3770.

United Artists has announced that "Apocalypse Now." Francis Ford Coppola's costly epic about the search for a deranged Green Beret commander in Vietnam's mountains, will have its world premiere at the Rivoli in New York on April 7, 1978. This also happens to be the date of Coppola's 39th birthday. Originally, a Christmas premiere was anticipated, so this announcement leaves the competition for blockbuster honors in 1977 to the big sciene-fiction pictures, George Lucas' "Star Wars" and Steven Spielberg's "Close Encounters of the Third Kind." The Spielberg film, a speculative suspense thriller about UFOs, is scheduled to open on Oct. 31 in New York and Los Angles and Dec. 14 in other metropolitan markets, including Washington.

The August issue of More carries excerpts from a rather extraordinary, presumptuous telegram sent by Coppola to President Carter soon after he took office, predicting that the "entire government will appear ridiculous to American and world public" unless Coppola received the cooperation he had been seeking from the Department of Defense in the production of "Apocalype Now." If this appeal was intended to secure the cooperation he claimed to need, which seems doubtful, it failed. From start to finish, the Department of defense declined to assist "Apocalype Now," and given the premise of the original screenplay, any other policy would seem incredible.

However, there's a kicker to the story: Coppola hired Carter-campaign publicity man Gerald Rafshoon and current White House pollster Pat caddell to devise a publicity campaign for the movie at a reported fee of $500,000. If this item can be credited, it invites speculation about the role of UA's own advertising and publicity people in the preparation of "Apocalypse Now" for market. Are they expected to sit on their hands until the Rafshoon-Caddell concept materializes, assuming it does?

Coppola reportedly has mortgaged himself to the hilt to guarantee the completion of "Apocalypse Now," costs of which have approached $300 million. Meanwhile, he is serving as executive producer on "The Black Stallion," the first feature directed by Caroll Ballard, regarded for many years as one of the most visually gifted young filmmakers in the country. Mickey Rooney, Teri Garr and a juvenile actor named Kelly Reno are featured in this adaptation of Walter Farley's best-seller, originally published in 1941, about a boy's obsession with an Arabian stallion. Production has begun near Toronto and will conclude on locations in Sardinia and Rome.