WE ARE pleased to be involved in an endeavor which will allow the public to acquire fine old photographic images at a price which all can afford," said the handmade sign hanging from the Gates & Tripp pushcart, which was parked in Boston's newly restored Faneuil Hall Market-place.

In a photography market devoted largely to doing the opposite - keeping prices high and creating artificial rarity through overpriced limited editions - this seemed the beginning of a small revolution that had been sitting arounf waiting to happen.

And there were the results: dozens of beautiful old images of the 19th-century American sailing ships and city scenes, cowboys, steam engines and daredevil flyers, all dating from between 1850 and 1930. Another sign explained that the photographs were recently printed, but from original old glass negatives, owned by the firm of Gates & Tripp, headquartered elsewhere in Boston. The photographs were selling - and selling and selling - for between $7.50 and $15 each.

That was the Bicentennial winter of '76. One year later, Gates & Tripp had moved from the pushcart into classy space in the South Market Building, the newest phase of the expanding Faneull Hall Marketplace, Boston's answer to San Francisco's Ghirardelli Square.

A request to speak to one of the owners - Gates or Tripp, if they were still alive - brough a startling reply: "I'm Caroline Gates," said a young woman, and the only available clerk. "And this is my partner Cherie Tripp." Both were 28, and, it turned out, about to begin grossing their second $100,000 after only 1 1/2 years in period photos.

They were also making plans to open a branch in Newport, R.I, this summer, and in New York City next fall. They had already gone into publishing note cards, posters and calendars and were commencing national distribution of their images. As of this month, their wholesale arm, "Period Photos," has shows of 40 images on view at the May Co. in Akron, Ohio, and at shops in Dallas and Houston.

The first Washington showing of Gates & Tripp's images has just opened at the Intuitiveye Gallery, 641 Indiana Ave. NW, where $1,000 worth of photographs were sold during the three-hour Sunday afternoon opening. Prices are $3 higher outside Boston. 'Boston's the Best'

"We couldn't believe what was happening," say the partners, who first met when New Yorker Gates, an art history major fromBrown University, and Pittsburgher Tripp, an English and business major from Boston University, were selling limited editions for somebody else in Boston. They decided to try a gallery of their own on the Boston waterfront in 1975, selling prints, crafts and contemporary photographs, in which both had a long-standing interest. "But it was the French-cut T-shirts printed with our slogan, "Boston's the Best," that kept us afloat," says Tripp, who worries about the finances.

"It was during our search for a good Bicentennial show that we stumbled into the period photography business," says Gates. "Cherie tracked down a collector of old glass plate negatives named Charles Woolley, who had been marketing prints from his negatives, mostly in antique shops. These images of historic sailing vessels and scenes of old Boston had been taken by turn-of-the-century photojournalist Orville Raan, who worked for the Boston Globe and Transcript. Woolley wanted prices low so that people could share them, and he shaped our thinking at an early stages."

A show was mounted and sold out immediately. "We felt we'd found in glass negatives a way to do in photography what had been done with prints in the '60," says Gates. "I think it was a combination of the photo boom, the new Bicentennial interest in American history that made the idea of period images click."

Gates & Tripp put two photographers to work full-time printing images on fiber-based paper, washed to archival standards. Everything was matted, and instant framing was available at close to cost.

Meanwhile, they hastened to hunt up all the good glass negatives they could find, buying what they could, including thousands of portraits from the old Boston photo firm of Southworth and Hawes, which are now being kept in a bank vault as collateral against a $25,000 loan. "Four banks turned us down until Harvard photography curator Davis Pratt vouched for the value of the glass," says Tripp.

They also entered into exclusive arrangements with several large collectors, including Woolley; Marshall Cook, who prints from his own collection of early views of Martha's Vineyard; and, most important, historian Martin Sandler, who owns thousands of glass negatives, in addition to thousands more to which he has exclusive access in various historical societies where he is consultant. The institutions receive royalties in exchange. Gates & Tripp have also used some images from public collections like the Library of Congress.

Meanwhile, other demands were being made upon the talents and resources of the young firm. Gates & Tripp was asked to create photo murals for restaurants, to provide appropriate old images for office walls of old Boston firms, to serve as picture researchers and as agents for vintage material. This year the firm expects to gross "well over $150,000," according to Tripp. That includes income from the pushcart, which the firm as kept to snag the impulse buyers who miss the shop.

Little is known about many of the photographers in the Gates & Tripp collections, in some casesnot even a name. "There were dozens of excellent photographers who are not yet known," says Sandler. "We try to get them before they get into the history books." By which he really means other people's history books. He has written several of his own, introducing his photographers therein, including "This Was New England," currently up for a Pulitzer Prize.

The most outstanding photographer among the new old talent at Gates & Tripp is T.S. Bronson, a turn-of-the century Connecticut physician who gave up a medical practice to devote himself to photography. Sander bought the 40,000 glass negatives found in Bronson's basement after his death. "Bronson's 'Ladies on the Beach' can stand alongside any photograph Stieglitz or Strand ever took," says Sandler. it is hard to argue.

Though Gates & Tripp seem to be the largest commercial firm currently in the business, they are not the first to make old images available at low cost: "The Library of Congress, George Eastman House, the National Archives, the Smithsonian and other public institutions have been doing it for years, and virtually at cost," says Jerald Maddox, curator of photography at the Library of Congress, where prints from negatives by Mathew Brady, Timothy O'Sullivan, Gertrude Kasebier, Frances Benjamin Johnston, Walker Evans and others - 8 million images, in fact - can still be ordered for $3.50, with mat-finish exhibition-quality prints available at $10 extra.

"The difference is," says Maddox, "that there wasn't much demand for old images until the current photo boom. Now institutions, public and private, ar beginning to publish. The Royal Photographic Society of London, for example, recently published a portfolio of recently printed images by 19th-century photographer Henry Peach Robinson, largely for the purpose of raising funds. Eastman House has published new prints from old negatives of Lewis Hine, far superior in quality to the originals."

In a related commercial venture, Time-Life Books recently published and sold out a limited edition portfolio of 10 Mathew Brady portraits printed from original negatives, but kept the price dowm to $150, thereby distinguishing itself from the overpriced, dealer-inspired, make-a-buck ventures now rampant.

In one other final development, University of Chicago photography professor Joel Snyder has found a way to reproduce not only the look of old sepia-toned prints, but to actually recreate the original albumen papers and chemicals, only with greater staying power. These re-creations, all watermarked as such, are currently available chiefly to teaching institutions and collections where handling the fragile vintage prints is no longer advisable. The future possibilities, however, seem infinite, if not all good, should these skills fall into less forthright hands.

Which brings up the question of what happens to the high-priced photo market if this proliferation keeps up? "In this respect, the dealers who started the photo boom have created their own monster," says Jerald Maddox. "They are bound to be nervous, and as a result they have been building up the mystique of the vintage print, and the importance of the 'esthetic interpretation of the printer.' But the argument is specious, for before Stieglitz, many photographers didn't even make their own prints. Surely Brady, O'Sullivan, Thomas Annan and others did not. In other cases, such as Hine, later prints are clearly the better."

"The question of which print is actually best is ultimately a matter of connoisseurship, not chronology," says Library of Congress graphics expert Alan Fern. "I think we need to take a closer look at all these emanations and vibrations collectors say they get only from vintage work," added Joel Snyder.

Another obvious put-down of this low-priced market became obvious at the recent Corcoran symposium on photography, when the word "reproduction" was repeatedly used by dealers. As these dealers well know, these photographs are no more reproductions than any others printed from the same negative, whether from the artist's hand or not. "The unique thing about photographic negatives is that they do not die with the photographer," points out Fern. They are also uniquely and inherently reproduceable as long as the negative lasts.

"As long as people know what they're getting, and the photographs aren't being passed off as vintage," he adds, "it seems to me that the real issue isn't whether the photo exists in one print or 500, but rather wheter it was worth printing at all." A Good Investment?

Are these Gates & Tripp photographs then good investments? "Of course not," say Gates & Tripp & Say Gates & Tripp & Sandler. "It's the image people are buying from us, not precious object".

"But Currier and Ives never meant to issue precious objects either," adds Sandler. "To the contrary, they were attempting to do what Gates & Tripp are doing: get their images out for the pleasure of the masses at prices people could afford. Now Currier and Ives prints are highly valued and very expensive. The fact is, you never know."

Famed National Geographic photographer Volkmar Wentzel, however had no doubts when he first encountered the Gates & Tripp photographs now at Intuiveye. "I think it's high time," he said. "By any standards these pictures are absolutely fasicating."