Early last week, Jan Kofman, a historian and editor for the Polish underground magazine Krytyka, was hustled from his cell at the Rackowiecka prison here. By way of explanation, a guard pointed to a vague headline in the newspaper Zycie Warszawy: "The implementation of the humanitarian initiative."

Hours later, Kofman called his wife from a phone booth and surprised her with the news of his release under a modest and relatively uncelebrated clemency program that communist authorities have initiated for political prisoners.

"It was very unexpected," he said. "Even the families were not informed. The authorities are handling this in a very quiet way."

The official PAP news service did say tonight that 75 of the 368 officially recognized political detainees had been freed in the last week, and more releases were expected.

Most of those let out had been charged with, but not tried for, such offenses as distributing forbidden literature or demonstrating.

While welcoming the clemency, both prisoners and opposition activists are calling the proceedings a disappointing retreat by the government of Gen. Wojciech Jaruzelski from its seeming offer last month of a formal amnesty following the election and installation of a new legislature.

"This measure will not help the situation much, because the promises were much greater," said Kofman, who was imprisoned five months and awaited trial on charges of printing and distributing Krytyka. "This is not a real amnesty. Society expected much more."

Opposition leaders argue that even a broad amnesty would be unlikely to have a lasting political benefit. "What people are fighting for is not amnesty but political rights like freedom of expression and freedom of trade unions, and as long as those rights don't exist, people will be in prison," said Zbigniew Romaszewski, a Solidarity human rights activist.

Jaruzelski first mentioned the possibility of an amnesty during a visit to the United Nations in early October, saying it would depend on public support for the Oct. 13 elections to the legislature, or Sejm. Government spokesmen later called the elections a success and said an amnesty measure could be submitted to the Sejm, which is required to approve such measures.

Subsequently, however, the communist-dominated Patriotic Movement for National Rebirth coalition formally called for the more modest step of clemency for prisoners on a case-by-case basis.

The government's formal announcement of the program did not use the word amnesty and further conditioned the move by saying that the "compassionate mitigations" were "not expected to cover" persons who had previously been arrested or benefited from amnesties in 1983 or 1984.