In the age when successful magazines are supposed to be awash with color, perfumed with advertising inserts and printed on paper as glossy as a freshly dishwashered plate, The Nation today celebrated its survival for 120 years as a publication gray with words, short on pictures and heavy with moral outrage.

"We're planning few changes," editor Victor Navasky said of the magazine cover that looks surprisingly similar to the first one published on July 6, 1865.

The paper could be slightly heavier, he hopes, the ink less likely to rub off on one's fingers. The cover, which offers highlights in one color -- often red or green -- may change sometime soon.

"But nothing will be really radical," Navasky said, adding that the entire staff was being consulted about a potential revamping of the magazine. "Frankly, there is some sentiment for dropping the color."

As one of the last voices of the indignant left in this country, The Nation may have found a simple secret to survival: It has not succumbed to the marketing masters trying to sell clothes and technological gewgaws to an audience that prefers spending its money on books. But while it has held steadfastly to its own self-imposed standards, the magazine has also found patrons, rich believers in its cause who are willing to help make up its deficits.

As of December last year, the latest angel has been Arthur L. Carter, a Connecticut multimillionaire who has turned a good segment of his energy to publishing.

With promises to make up losses of about $200,000 a year, Carter, who is reportedly worth about $100 million, has said he hopes to have the magazine out of the red in five to 10 years.

"I think there is not enough liberalism in the country or the world," said Carter, who founded the precursor company of Shearson Lehman Bros., now the banking arm of American Express. "I wanted to involve myself in magazine journalism, and this was the only one that represented a position of dissent that I approved of."

"One of the reasons we went into business with Carter is because he understood what The Nation is about," said Hamilton Fish III, publisher of the magazine and a renegade liberal in a historically conservative family. "We are a symbolic resistance to the superficial improvements in the culture of journalism."

It is now an easy axiom of the left that The Nation, The Village Voice and perhaps Mother Jones are among the few publishing vehicles that challenge the establishment. The other member of the chorus, The New Republic, has changed its creed. Once a voice of liberalism, under owner Martin Peretz the magazine has turned toward the right -- with Peretz supporting military aid to the contras in his latest issue, for example, to the chagrin of many of his remaining liberal readers.

"It's a boring magazine," said Peretz recently of The Nation. "It's not a magazine; it's a memory of a magazine."

Although some of Peretz's readers say the same of The New Republic, Peretz was referring to the golden days of The Nation when its pages included works of Emily Dickinson, Henry Wadsworth Longfellow, James Agee, Upton Sinclair, Henry James and Willa Cather.

"It's not a magazine; it's a church," Peretz continued. "You go in and you do the catechism."

Much like Human Events and National Review on the right, The Nation in fact does preach to its believers, but with no apologies.

"You give them the facts and figures they need; you fortify them," Navasky says of subscribers that he claims number in the range of 70,000. "You discover the converted and put them in touch with each other."

Fish, who bristles more visibly at Peretz's suggestion that his magazine is too predictable, says with some sarcasm, "Marty has certainly taken the high road. Ever since he went there, there has been a steady tattoo of unsolicited envy coming out of their offices."

Of The New Republic's less predictable political line, Fish says: "The Washington dinner party turns right and The New Republic is fast in its wake. When the center comes back a bit, The New Republic will correct its course."

There's another difference, Fish adds. The celebration today of The Nation's 120th year was supposed to be a far less lavish event than The New Republic's 75th-anniversary party last year.

"We're not going to have an exclusive black-tie party with Jeane Kirkpatrick and Henry Kissinger," Fish said.

However, Fish and others at the magazine spent some part of today explaining why a reception and dinner party were closed to the press and to people who had not paid $1,000 to attend.

"The feeling is that these are the closest supporters who have to be thanked," said a spokesman for the magazine, adding that reporters could catch guests going in much the way they do for White House functions.

The big party, estimated at 3,000 strong for The Nation's loyalists, included others not around for the Peretz event -- Joan Baez, George McGovern, Studs Terkel, E.L. Doctorow, Kurt Vonnegut, I.F. Stone, James Baldwin and David Halberstam.

Like a Who's Who of the '60s, the celebrants included many who still believe fervently in ideas that have dimmed for many in the nation 20 years later. And some see this gray little magazine as one of the few that still speak their language, however anachronistic it seems to others.

Says Vonnegut: "I think it stands for good reporting in this era of mendacity when people lie for what they consider the good of the country."

Or as Oriana Fallaci says in the letters to The Nation this week: "No one with an honest mind can deny that in a time when journalism indulges so much and so often in being a business to entertain people with amenities or a show business run by illiterate cowards, The Nation still has the guts . . . "

For many of its other fans, who often disagree with its politics, The Nation has become a traditional pest, needling from the left and thus staying in line with the prescient credo of its original editor, who wrote almost 120 years ago: "We profess to supply opinions exactly as we have formed them, and not in the shape in which they will be likely to please or encourage or console."