Ad industry puzzle: how to remove stains on its own public image.

Ad makers have an image problem. Most advertising people think of themselves as highly trained professionals who perform an essential service in a free enterprise economy.

Consumers, on the other hand, tend to view admen as little more than pitchmen and con artists - sometimes peddling sleazy wares with advertising that is too often offensive rather than informative and entertaining.

It's reached a point where this negative attitude has become so pervasive that it colors the self-image of some of the people who produce today's advertising. Recently Advertising Age, a respected trade journal, asked ad agency executives whether they would encourage their youngsters to pursue careers in advertising.

''More than anything, I hope they don't go into it,'' responded the father of two young daughters who is a management supervisor in an agency noted for its blue-chip industrial accounts.

William Tragos, a father of four and chairman of TBWA, a large international ad agency, gave this negative response: ''The client has the money, and the agency takes the order. If it doesn't do what the client wants, sooner or later it loses the business. Until our business becomes trusted and respected, I don't want my kids in a subservient business like that.''

Donald R. Keough, president of the Coca-Cola Company, one of the country's largest advertisers, blames ad makers for their own poor public image.

''The greatest tragedy of the advertising business through all the years that I have been part of it has been the failure to build an alliance with the public itself,'' Mr. Keough told the annual meeting of the American Association of Advertising Agencies earlier this year. ''And the startling fact, as you all know, is that public discontent - or public derision - of advertising appears to have increased. . . .''

Mr. Keough then went on to congratulate the organization for having put its finger on the cause of the public's disfavor with advertising that is ''silly, insulting, tasteless, and demeaning in creative execution.

''The question, of course, for all of us,'' he continued, ''is have we copped out on our own good taste? Have we developed such professional objectivity that we cannot express our own subjective outrage at advertising that insults all wives, all daughters, all fathers, and all sons of all demographics? I do not like it when a Coca-Cola commercial sits back-to-back with commercials that seem to be talking to that ancient advertising target: the adult with a nine-year-old mentality.'' Responding to the issue, the association's new chairman, Paul C. Harper Jr., pledged to continue the association's quest of an improved public image. Mr. Harper, chairman of Needham, Harper & Steers, one of the nation's 10 largest ad agencies, lists this as a top priority for the association.

In fact, Mr. Harper indicated the problem was too important for the chairman alone. One of his first official acts was to ask John O'Toole, the vice-chairman and chairman of the board of Foote, Cone & Belding, another big and prestigious ad company, to set up a committee to study the problem and recommend ways for dealing with it. The committee will convene next month, but Mr. O'Toole is already firing off memos and background information to committee members.

In a recent interview with the Monitor, Mr. O'Toole, the author of a widely acclaimed book, ''The Trouble With Advertising'' (Chelsea House), says most people are thinking of TV commercials when they complain about advertising: ''It's the intrusive nature of the medium,'' he writes. ''If you see an ad in a magazine or newspaper you don't like, or feel is offensive, you have the option of turning the page, which is what most people do. But TV is sequential. So it's not so easy to skip the commercials.

''Television programming in the United States tends to be insulting because it's appealing to a mass audience. But advertising has to take responsibility for the 'Madge and Marge in the kitchen' commercials. Two areas where we're culpable are the number of messages - what has been defined as commercial clutter - and the dull and predictable nature of the messages.''

The association has been aware of this image problem for a number of years and has done occasional studies, Mr. O'Toole says. Now, ''I hope to see improvement,'' he adds. ''But it's too early to predict what the committee will recommend.''