The larger-than-life murals dominating the grand lobby of the new Labor Department, which were dedicated on March 4, came to birth in a thirty-one-month "Renaissance adventure" led by New York artist Jack Beal. His four twelve-foot-three-by-twelve-foot-six panels are the first publicly funded paintings to be incorporated into the design of a federal building in Washington in thirty-five years.

The return to realism in public art - the last example of the genre is Mitchell Jamieson's 1942 tempera-on-canvas mural of Marian Anderson singing on the steps of the Lincoln Memorial, which hangs in the Interior Department - is largely the product of thee determination of Richard Conn, head of the Labor Department's Bicentennial Office, and Beal's own powerful persuasiveness.

For a generation government art has meant abstract sculptures and stabiles outside federal buildings, equally non-representational bas-reliefs and mosaic murals in the lobbies.But Conn wanted something else for the Labor Department's new $95 million edifice that strddles Interstate 95 next door to the District's Municipal Center. In a series of fierce drawings, mock-ups and memos, one of them running to eight single-spaced, closely argued pages that concluded with a threat to resign the $150,000 commission if he didn't get his way, Beal unfolded to Conn, to Donald W. Thalacker of the General Services Administration's Art in Architecture Program and to the Visual Arts Committee Panel of the National Endowment for the Arts what that "something else" should be.

Beal's alternative is a four-panel, four century vision of the history of labor in American that has the ambience and style of Diego Rivera's "Liberation of the Peon" murals in Mexico's Ministry of Education and Thomas Hart Benton's nine-panel depiction of "American Today" in New York's New School of Social Research.

"The subjects for my paintings are not actual historical incidents or glorifying well-known heroes of the labor movement," Beal said recently. "I drew people who were close to me but not celebrated or publicly recognized. The real heroes of American labor are everyday people working well and hard at their everyday jobs."

The six-foot-four-inch painter sketched out his experiences in a series of conversations in the loft studio in New York's Chinatown where he put the finishing touches to his epic work. Sprawled in an ancient easy chair in the eerie light of a winter afternoon, framed by the monumental panels that are - for the present at least - his masterwork, Beal rolled a pinch of Copenhagen snuff, snorted it, and declared:

"My whole painting career I've searched for an equitable balance between human needs and aesthetic needs. It's a very exciting conflicts.

"Clearly I'm a modern painter, but my interests are extremely varied and I try to draw stimulation from all kinds of sources . . . I'm making twentieth century pictures, but I've learned a lot from my sixteenth and seventeeth-century colleagues."

Then, in obvious anticipation of attacks by critics who see no place in contemporary art for representational work, he continured: I hate the phrase 'going back to realism.' It's like 'going back to nature.' We've never left nature.We've never left reality. I'm trying to paint people and things the way i think most people see people and things. And I'm trying to paint them as they are."

When Walter Henry Jack Beal (He's named for a "famous" uncle, the author of an Agriculture Department treatise entitled "Barnyard manure") speaks of his artist colleagues of the past, it is evident that they mean more to him than simply textbook techniques.The grand names sound like family friends as he expatiates on te exploits of Caravaggio, the intense discipline that charcaterized the working methods of Piero della Francesca and Masaccio, the family studio operated by Tintoretto. His self-identification with the great age of Italian public art is wholly unabashed.

"We had to reinvent the Renaissance!" he exclaimed in one conversation. "I had to learn to draw all over again."

In the face of the 848-day government deadline ane the massive proportions of the project Beal envisaged (an average of nine life-sized figures in each panel), he had little choice but to revive the studio traditions of he heroes of sixteenth and seventeenth-century art. Assisting Beal were his wife, Sondra Freckleton Beal, an accomplished water colorist, and two apprentices, Dana Van Horn and Bob Treloar, who at one time were students of Beal's at San Diego State College.

Each morning the four would assemble for breakfast in the converted mill house that is the living quarters of the Beals' farm outside Oneonta, New York, to discuss the day's plan of attack. Then they would troop over to the studio that was specially built for the project.

Because of the tension created by the huge area of stretched canvas only one person could work on a mural at a time. After the pastel preliminary drawings were scaled up by a grid system and transferred to the canvas, Beal made all the initial color decisions. Areas of dark and light colors were laid down by the group, while Beal did al the drawing and painting of figures.

"Jack never abdicated responsibility," said apprentice Van Horn. "He made things so clear and established a spirit to work with and gave us a certain amount of responsibility to inspire us to give our utomost . . .

The atmosphere at the studio crackled with creativity. Work went on far into the night, and ten-, twelve- and fourteen-hour days were normal occurrences. The only recreation beyond trips to the mailbox was lunch crew cooked and ate together.

Van Horn, perched on a scaffold in one corner of the studio, would add meticulous details to the bark of a tree in the seventeenth century mural. Periodlically he would shift his gaze to study sections of bark collected on the farm that he had nailed to a nearby wall. Sondra Beal, hunched over a corner of the eighteeth century would paint from life - rocks, duck and wooden beams. Treloar, assigned to the twentieth century, would bring in pieces of chrome and other metal for his panel's laboratory section.

"When there were problems," said Van Horn, "we had a little meeting and Jack would make the decision. Much of our work was repetitive. Once I learned how Jack wanted it done I generally repeated it. It took me a month and a half to paint the bark. Utimately it had to be right because if it wasn't it would have to be done again . . .

"Jack wanted it to be a valuable experience for us, and it was. It was totally instructive. He had it in mind from the beginning for it to be a Renaissance adventure."

Before he took the GSA commission Jack Beal had never painted more than two life-sized figures on a single canvas. Now he was dealing with up to ten figures to a mural. During the week the studio was host to a variety of mannequins clothed in period costumes.

On weekends the mannequins were replaced by visitors from New York, friends of the Beals who would model for the artist.

"My friends," said Beal, "are in all of the murals. The pressure have been enormous, but the rewards of working with three other people and to have ll of my friends come and pose for me . . . it has just been a phenomenally good experience."

In conscious imitation of Renaissance custom, Beal made sure that the face of his "patron" appeared in the murals. The Labor Department's Richard Conn is to be seen hard at work at a fantasy textile machine in the nineteenth century panel. Conn's secretary, Vivian Twisdale, also appears, as the black woman in the twentieth century panel.

Twisdale's features were hastily painted in after Beal had transferred the murals to the New York studio, thinking that all he had left to do were the "finishing touches." Unexpectedly, the woman who had originally posed for the figure announced she did want to be included after all. Beal swore vigorously, then flew to Washington, sketchbook in hand, to record the features of the stand-in.

Finally the murals were complete. Beal examined them reflectively during one of our conversations. "I want young realist painters to see these mural s and says, 'Goddammit, I can do this.' They might hate them, but the result will be same - more realist art.

"Realist art is made for public places. It's an art made for the people."