For years it was a journalistic cliche' that newspapers criticize each other gently, themselves not at all.

But times have changed, including The New York Times, as readers noted in yesterday's edition.

There under the heading "Editors' Note," which is how The Times issues its most important clarifications or retractions, was a four-paragraph item about a Monday story on real estate and publishing mogul, Mortimer B. Zuckerman.

The note, considered one of the toughest self-critiques that has appeared in The Times to date, concluded that the article by Jane Perlez "violated The Times's standards of fairness."

Perlez, a respected veteran reporter who returned to New York recently after several years in the Washington bureau, could not be reached yesterday.

The article, headlined "Mortimer Zuckerman -- A Developer With Verve for High-Stakes Dealing," portrayed Zuckerman as a real estate millionaire who "seems always to be looking for more." Owner of The Atlantic and U.S. News & World Report, Zuckerman ". . . has befriended writers, editors and television personalities in an effort to win a place in their world," the 1,997-word article said.

The clarification, which may have caused many who missed the story to read it, cited use of "opinionated phrases and unattributed characterizations" that "established a tone that cast its subject in an unfavorable light."

"The paper's policy is to avoid such opinionated wording in its news columns, and to omit personal criticism by sources who insist upon anonymity. The pejorative phrases and anonymous criticism created an unbalanced portrait. They should not have appeared."

"I was totally surprised by what was in The Times, but I think it's a testament to their editorial integrity," Zuckerman said yesterday in a telephone interview.

Zuckerman acknowledged that he was extremely upset about the article, but refused to discuss whether he had complained about it to Times executive editor A.M. Rosenthal, who sent calls about the matter to metropolitan editor Peter Millones.

Zuckerman would only say he was surprised by the editors' note, and that the "focus" of his concern was directed more at what he called "factual inaccuracies" in the piece. He added: "My understanding is that there will be a correction of a large number of factual errors as well."

Times metropolitan editor Millones said he knew of no other corrections planned by the paper on that article. He said he had not read the story before it appeared but when he saw it in the paper, believed it deserved comment or clarification.

"When I read it, it was quite clear that it violated our standards, so I initiated the editors' note after discussing it with Abe Rosenthal," Millones said.

Millones, calling Perlez a "good reporter," said that neither Perlez nor any editors who worked on her article are in danger of demotion or losing their jobs as a result of the story.

"Life goes on. You make mistakes; you try to correct them. We all live and learn," Millones said.

"They're all okay. I'm the only one who's bleeding. I wrote the note, and I'm responsible," said Millones.

Friends of Zuckerman were divided about the Perlez piece. Some saw it as portraying Zuckerman as a "Sammy Glick-type," as several put it. Others thought it was "harmless," as one described the article, or "generally upbeat," as another said.

Sources familiar with the progress of the story said Zuckerman refused to give Perlez any more than a very brief interview, despite persistent efforts on her part to talk to him. "That's always a mistake," said one of those sources.

Some said they would have advised Zuckerman against complaining, fearing that it would call attention to the piece and make it appear more negative in retrospect.

"I'm still happy that this took place," Zuckerman said.

Out on Long Island, Newsday's colorful eminence Murray Kempton recently wrote a column that seemed to tread ever so strongly on his liberal credentials. Crafted with Kempton's usual grace, this column talked about the compassion of Richard Nixon.

Richard Nixon? Kempton's friends and fans read, with some concern. Compassion?

Kempton quoted the ex-president as saying there are two parties in this country -- one with a soft heart and a soft head. The other, Nixon's own party, has a hard head and a hard heart "and sometimes that is bad," he quoted Nixon as saying.

Then Kempton called for the present president to listen to his disgraced predecessor. "And there sits Richard Nixon, equipped with all the enormous education of his wounds," he wrote, "and we have no way to use him."

Kempton said this week that he went to visit Nixon recently in one of the various sessions Nixon has been enjoying privately with many members of the press. "I was struck with how smart he is, particularly in dealing with other people's business than his own," the columnist said.

Kempton then penned Nixon a note saying he had decided not to write about their visit as a matter of principle. Nixon wrote back that this was the highest accolade a journalist could bestow, but before that letter reached him, Kempton said that "in the meantime, a week passed and I was desperate, so I wrote about it."

A little sheepishly, Kempton then sent another letter to Nixon explaining that journalists acted toward information the way Harold Stassen did about running for president.

"He'd swear he wasn't running; he'd swear that he wouldn't even think about it," Kempton said. "And then he would pass the White House.

"I never got an answer to this letter so I thought he was sore," Kempton recalled.

Not so. An ardent admirer of Kempton who watches New York's courts for The Washington Post, John Kennedy, sent Nixon the column, and the former president wrote back that he had been "privileged" to know Kempton and "to have had the benefit of his wise counsel for over 35 years," adding that Kempton is "one of America's most perceptive political columnists."

"I was touched," said Kempton. "There's one quality which Nixon has which I always find enchanting -- he social climbs down."

David Burgin, recently departed editor of the Orlando Sentinel who has taken on editorship of the San Francisco Examiner, has been on something of a hiring spree.

Under the watchful eye of publisher William Randolph Hearst III (dynamic grandson of the William Randolph Hearst), Burgin has lured columnist Warren Hinckle from the San Francisco Chronicle.

Frank McCulloch, who had recently retired as executive editor of the McClatchy newspaper chain, was writing an article about Hearst for California magazine when Hearst and Burgin turned the tables on him and began interviewing him for their managing editor spot.

"He had to give back his advance," Burgin said proudly after McCulloch was coaxed on board.

Still, the hire that has the Examiner staff and most of the old-time journalistic community agog is none other than Hunter Thompson, whom Burgin has brought aboard in some as-yet-untangled plan to allow the Gonzo master to write a weekly column on the media for the paper while he finishes his book on live sex.

Asked how he will cope with Thompson's well-known antics and 1960s life style, Burgin laughed and said, "I have no control over his personal life."