With the entry of Bob Brady this week, the announcement season for the Democratic mayoral primary apparently has come to an end.

And the announcements themselves, although steeped in ritual and lacking in drama, have told voters a lot about the major candidates and the messages they will pitch between now and May 15.

Of the five events, Brady's was the most muscular, Dwight Evans' the most single-minded, Tom Knox's the most personal, Chaka Fattah's the most thematic, Michael Nutter's much the earliest.

In the world of electoral politics, the announcement of candidacy is an institution in flux. In recent weeks, Democratic presidential hopefuls Barack Obama and Hillary Rodham Clinton launched their 2008 presidential campaigns with brief Webcasts.

But whatever the setting or medium, the occasion remains one of the few moments when a candidate is totally in control of the situation - free to say what he or she wants, when and where he or she wants, largely free of criticism, before an audience of his or her choosing.

So the image projected, as well as the subjects discussed or ignored, provide insight into what the campaign brain trust considers to be central in terms of a candidate's strengths to highlight and weaknesses to address.

Consider Brady. After months of public wavering over whether to run, the congressman used his moment in the spotlight Thursday evening to signal his commitment to the race. His announcement was loud, crowded and high-energy, with the candidate often shouting to convey his enthusiasm.

Brady highlighted what he considers his chief asset, that he is "a leader with the strength and experience" in solving problems. Like everyone else in the race, he touched on crime and education.

One word he did not utter was "reform." He made no mention of trying to alter the city's political culture or the way business is done at City Hall. He has been very much part of that culture, serving as chairman of the Democratic City Committee for two decades.

Among the other candidates, only Evans' launch in December was a match for Brady's in crowd size or decibel level. After finishing last in the five-way mayoral primary eight years ago, Evans wanted to show the depth of his support this time around.

Unlike his competitors, Evans chose to focus his announcement on a single topic, crime, proclaiming: "This city must be safe or nothing can happen."

In the weeks since, the veteran state representative has addressed other subjects in some detail. Crime, though, continues to be his focus.

Knox staged a quieter, more intimate sort of event when he announced in late November. Most of the crowd, such as it was, was drawn from a nearby drug-treatment center by the promise of a free lunch.

But what mattered most to Knox was the setting, a grassy hillside near the public housing project where he grew up.

"My name is Tom Knox," he said that day, " . . . a proud son of the Abbotsford projects, a product of poverty."

His life story, that of a millionaire businessman who rose from humble roots, has been the theme of the television commercials that have won him support in recent polls.

In the case of Fattah, who made his announcement earlier in November, the backdrop also was the message. The presumed front-runner at the time, the congressman held the event in front of the School of the Future, a symbol, he said, of his aim to create "real opportunities for all Philadelphians."

The theme provided him with a rubric under which he could tell his own life story and discuss, in a general way, the issues of crime and education. It remains his campaign slogan, with the specific policies being fleshed out one by one as the weeks pass.

Nutter's announcement took place in July and stands out for that reason. With skeptics wondering whether he would give up the security of a council seat to become a mayoral candidate, he moved decisively to resign his seat and become the first man to enter the race.

For Nutter, too, the setting was important, the porch of a new rowhouse in the Parkside neighborhood. It allowed him to talk about his own neighborhood roots and the initiatives in which he, as a councilman, had played a role. "I'm ready to lead right now," he said.

For all the candidates, the time when one could control the message so completely - except through paid political advertising on television and radio - has come and gone.

The announcement season is over, and the race is becoming fully engaged.

Contact senior writer Larry Eichel at 215-854-2415

or leichel@phillynews.com.