Frank DeFilippo and his boss at the Rosenbush Advertising Agency, Louis Rosenbush, were talking to a visitor about the finer points of political advertising last week when Rosenbush decided that he would show on his video cassette screen "the best and most honest spot ever made."

The commercial began innocuously enough with a car salesman named Williams standing in front of his new car lot in California, introducing himself and his business. Then, without the slightest change in manner or inflection, Williams informed his viewers that "if you buy a car from this bald-haired son-of-a-bitch you're gonna get taken like you've never been taken in your life."

The hilarious, though vulgar, car commercial served as a marked break from the simple, polished, admittedly dull ads DeFilippo had been viewing that afternoon for the company's major political client, Acting Gov. Blair Lee III. DeFilippo believes that Lee, like that car salesman, has a knack for being funny and irreverant, but that it would not go over on television.

"There's a certain drollery about Blair that is absolutely delightful in person," said DeFilippo, who used to be the press secretary from the man Lee succeeded, suspended Gov. Marvin Mandel. "But on television it comes off as a sly, arrogant type of remark. We can't risk it during a campaign."

And so there is nothing funny about any of Lee's television or radio commercials. They are designed, in fact, to present just the opposite image, an image that one campaign worker labeled as "Father Knows Best."

The announcer on the 30-second television spots can be heard, in a deep and serious voice, stating that Lee is "not flashy or flamboyant." His brochure finds him working at his desk in Annapolis, bracketed by the slogan: "You don't have to wonder whether Blair Lee can do the job as governor . . . he's already doing it."

"It's my basic feeling that there's only one issue in the campaign," said DeFilippo, "and that's whether the candidate is honest and has the ability to do the job.Blair is experienced, he works and likes to work. We aren't going to send him off on a canoe down the Patapsco River or have him jumping over hedges or acting like someone else."

The Lee campaign is expected to spend more than $200,000 on television advertising alone in its effort to convey the Blair Experience III image to the voters.

Napolitan, a veteran consultant from Massachusetts, has been conducting periodic polls to see whether Lee's image matches the voter's perceptions of him. These polls, according to campaign sources, have indicated two apparently paradoxical views: a disquiet with government as it is but also a negative feeling abot candidates who promise a fresh look and change.

"We think the people were smitten in 1976 by a theme of prayer and populism and now realize they got what appears to be a clumsiness," said DeFilippo, in reference to the changing perceptions of candidate and then President Jimmy Carter. "There's been a turnaround. The image of change is not as important as the image of experience."

Still, there are those who maintain that Lee's image has emphasized experience to the point of excessive dullness. When the 61-year-old governor visited one western Maryland town, a local newspaper captured his demeanor with the heading: "Blah Lee . . . Into his Dull Self . . . On the Campaign Trail with the acting, aching governor."

Lee's image consultants are relatively unconcerned about his negative portrayals in newspapers. "Television is the real ticket," said DeFilippo. "It's the medium that most accurately captures the candidate. [TEXT OMITTED FROM SOURCE] had attempted to tailor his imagery especially for an audience of black church-goers. "I have a vision of a New Maryland," he preached, his timing in imitation of Martin Luther King's "I have a dream" speech. "A New Maryland where there is equal opportunity for all. A New Maryland where . . ." The speech wasgreeted with police applause, if not indifference.