June 8, 1984

THE felicitous ease of Fairfield Porter's canvases cause many viewers trouble. ''Are they modern enough? Too French? Too pleasant? Hasn't this been done before?'' are questions that - the critic John Ashbery amusingly suggests - people guiltily raise while succumbing to their charms. Art, as we all know, must be difficult, intellectually challenging, and not, well, immediately accessible. On these counts, the Porter works flunk, as is readily apparent in ''Fairfield Porter,'' the first major retrospective of this influential realist (1907-75), at the Whitney Museum, Madison Avenue, at 75th Street (through Aug. 19). Yet these fresh, light-struck landscapes, intimate interiors, informal portraits and homey still lifes - made during and after the heyday of Abstract Expressionism - are certainly among the finest realist paintings produced in the United States since the end of World War II. Porter's work didn't lack for exposure during his late-blooming career, but viewed in this unprecedented depth (more than 70 canvases) and in light of the painterly realism that holds sway today, its presence takes on new authority. As with many figurative painters, his work got looser, even more ''abstract,'' toward the end of his life, - but it never abandoned what Porter called the ''visualness'' that was its basis.

When Gary P. Spoleta, the president of Shoney's Inc., visited one of his company's restaurants in Kansas City, Mo., three years ago, he was upset by what he saw. A flood of conventiongoers at lunchtime overwhelmed the coffee shop's staff, and a line of customers waiting for tables extended out the door. To help out, Mr. Spoleta started washing dishes and had the two regular dishwashers clear tables. A local Shoney's executive took over as host, and the hostess waited on customers. Three hours later, the operation was back to normal.

The 10th summit conference of the seven major industrialized democracies opened in London in a mood of modest expectation generated by repeated official warnings that neither bold policy initiatives nor ''magical solutions'' were likely to be achieved. (Page A1, Column 6.) Violence erupted in Indian cities arising from the Indian Army's attack Wednesday on the Sikh shrine in Amritsar and the death of more nearly 400 people, including a radical Sikh leader. The army occupied the Golden Temple in an attempt to end Sikh terrorism. (A1:5.)

HOMESPUN but eloquent pop, earthy blues, precise close harmony singing, post-Beat satire and surreal folk music are all in New York's clubs this weekend for people in search of quality cabaret. At Freddy's Supper Club, 308 East 49th Street, the pop singer and songwriter Bonnie Koloc is playing her first club engagement since appearing on Broadway in ''The Human Comedy.'' Miss Koloc won a Drama Desk nomination for best supporting actress in a musical and a Theater World award as one of the most promising newcomers on Broadway for her portrayal of Mrs. Macauley, a woman who loses both a husband and a son in war. The singer's success with the role - her first dramatic part since high school - suggested that she might be able to carve a future for herself in musical theater. It was a welcome boost for the Iowa-born Miss Koloc, who has made seven albums without having a hit. She is a popular star in Chicago, who made the move to New York just over two years ago. ''I decided it was put up or shut up,'' she said the other day about her move east.

Welpro Inc. of Seabrook, N.H., a 50-year-old maker of women's dress shoes, will cease operating July 1, Stanley Barr, president and son of the company's founder, told the 250 employees at noon today. Mr. Barr said the decision was made in response to Wednesday's decision by the United States International Trade Commission not to give tariff protection to American shoe manufacturers. He said he and his brother were going to go out of business ''before we run out of cash'' to meet the payroll. Another response to the I.T.C.'s 5-to-0 ruling that imports of cheaper shoes do not represent ''a serious'' threat to the domestic shoe industry came from Henry Clayman, president of P. Clayman & Sons Inc. of Salem, Mass., which says it supplies 50 percent of the innersoles used by the naton's domestic shoe manufacturers. The ruling ''defies logic,'' he said.