If God is in the details, then the Annapolis Historic District Commission surely is blessed.

Not so much as a shingle can be replaced or a sign hung in Annapolis' historic district without the approval of the five-member government agency.

"We are keeping Annapolis a town which retains its character and doesn't become a honky-tonk," said the commission's vice president, Harrison S. Sayre.

At times, the volunteers who serve on the commission have been derisively called nitpicking naysayers. Now they are working to foster a more positive image.

The commission has published a brochure to help residents understand the approval process; is preparing to offer workshops on preservation techniques; is making an effort to tell applicants how they can improve their designs; and is considering an expedited process for sign approvals.

The actions exemplify an attempt to educate a community that after 25 years still doesn't understand the agency's role, said Commission Chairwoman Donna Ware.

People still recall the time the commission insisted that a resident remove a plastic rose trellis and install a wooden one. And the commission made headlines by opposing a comic book store's sign that depicted Spiderman.

Commission member Michael Ricketts said he asked Mayor Alfred A. Hopkins to appoint him to the board a few years ago after a frustrating experience in getting the commission to approve changes he wanted to make to his house.

"I thought it was a terrible process," he said. "Most of the time they told you that you couldn't do something, but wouldn't tell you what you could do."

At the commission's most recent meeting, the agency speedily approved a half dozen items that had no opposition, such as creating a new curb and putting a sign on a downtown store.

Then the commission settled down to hear the more controversial petitions. For almost a half-hour they discussed whether the replacement windows one couple wanted were compatible with their 19th century home. By the time the couple left, they had been told specifically what kinds of windows were acceptable.

With the same thoroughness, the commission deliberated a few months ago its biggest project ever -- the proposed $55.6 million county courthouse. Although visitors to the downtown courthouse may never notice whether the top of a window is curved or straight, those were the kinds of details that commanded the commission's attention.

While attempting to protect Annapolis' historic character, the commission's decisions often have been more liberal than some downtown residents wanted.

The commission decided neon lighting was in keeping with the character of some downtown buildings, although the City Council later tried to outlaw neon as too tacky for the colonial town. The commission waived height and mass restrictions and approved the new county courthouse, although ardent preservationists complained that the courthouse detracted from the ambience of the surrounding narrow streets.

Joan Abel, a commission member since 1991, said historic preservation has to be balanced with common sense. "History is compilation of all past periods, including last week," she said.

One reason for the new attempt to educate the public is to dispel the idea that the commission is capricious and arbitrary, Ms. Abel said.

"We try very consciously to be objective," she said. "We're not reacting to a proposal on the grounds of whether we like it or dislike it, but whether it meets the guidelines."

When the Historic District Commission was created in 1968, many of Annapolis' 18th- and 19th-century buildings were in sore shape, rotting from years of neglect or marred by tacky additions.

Some of the city's most beloved buildings, such as the William Paca House, and the Market House, narrowly escaped the bulldozer in the years just prior to the commission's creation.

Opponents of the historic district commission maneuvered to place the agency's creation before a city-wide referendum, but underestimated residents' concerns for preservation. The measure passed by an overwhelming majority.

As a result of the ordinance, Annapolis was able to resist efforts to develop high-rise condominiums and office buildings. Today, many of the city's narrow, tree-lined streets are flanked with stately federal- and Georgian-style brick homes looking much like they did two centuries ago.

The commission has jurisdiction over more than 1,000 structures in the district, which is bounded by the U.S. Naval Academy to the east, Spa Creek to the south, College Creek to the north and Calvert Street, City Gate Lane, Franklin Street and Southgate Avenue on the west.

The guidelines the commission enforces include prohibitions against vinyl siding, sandblasting brick and painting brick that never was painted. Although the commission tries to ensure that new construction harmonizes with the city's 18th- and 19th-century architecture, it frowns upon new buildings that try to copy the old.

Despite the publicity the commission receives when it opposes a project, applicants win approval 90 percent of the time, said Ms. Ware.

"It's really made preservation work in Annapolis," said Ann Fligsten, of the Historic Annapolis Foundation, the agency that successfully lobbied for the creation of the Historic District.

The commission's efforts to educate the public and guide applicants through the process have won the praise of the town's business community as well.

"Businesses recognize the importance of the historic district," said Penny Chandler, executive director of the Greater Annapolis Chamber of Commerce.

Though the guidelines can be irritating, Ms. Chandler said most business owners realize that they profit from the town's historic charm.

Commission members say their most difficult period came during deliberations over the new courthouse. Business and civic leaders pressured them to approve the plan to keep the courthouse downtown.

At the same time, preservationists urged them to stick to the district's guidelines, even if it meant losing the courthouse.

Mr. Ricketts said the commission has only started to make the approval process easier to understand. The next step, he said, is to take a more active role in educating Annapolis about how it can preserve its history.

Part of this will be to teach residents to appreciate all phases of Annapolis' history, said Ms. Ware.