The carving of the phrase “The New York Public Library Stephen A. Schwarzman Building” five times into the mountain white marble façade of the flagship building of the New York Public Library is expected to take two months, the project manager for the restoration of the façade, Tim Allenbrook, said yesterday.

The engravings, in recognition of Mr. Schwarzman’s $100 million gift, the largest gift to the library in its history, should last longer. The names currently on the façade, of the library’s founding benefactors, John Jacob Astor, James Lenox, and Samuel Tilden, have been there since the building opened in 1911. Their names appear at 12 inches in height, compared to the 11/2 abd 21/2-inch heights designated for Mr. Schwarzman’s name.

Naming gifts are a common and accepted part of America’s philanthropic culture — in the Museum of Modern Art’s recent expansion, a name has been attached to almost every gallery, and New York abounds with examples. But engraving on façades is unusual.

The recently renovated Morgan Library does not feature the Morgan name anywhere on its façade, instead honoring its founders, J.P. Morgan and J.P. Morgan Jr., in gold-inscribed letters on a wooden wall inside the building. The Whitney Museum of American Art’s façade also does not bear the name of its founder, Gertrude Vanderbilt Whitney.

“Engraving names like this is extremely rare,” Mr. Allenbrook said. He noted that additional name engraving did not take place in two façade restorations of cultural institutions he recently oversaw, of the Metropolitan Museum of Art and the American Museum of Natural History.

The library, of course, has a tradition of engraving names, as witnessed on its façade.

The president of the library, Paul LeClerc, yesterday described the decision on the engravings — finalized less than nine months after Mr. Schwarzman began contemplating the gift — as appropriate to both the nature of the gift and the tradition of donor recognition at the library.

Specifically, Mr. LeClerc said an unrestricted gift is historic, citing as a counterexample a gift once made to further the study of shorthand.

“We’re very careful and deliberate here. We have very careful processes, and we are very, very conscious of our responsibility as stewards of the building,” Mr. LeClerc said.

Referring to the number of times Mr. Schwarzman’s name will appear, he noted that many gifts are recognized more than once within the library. For instance, rooms with two doors, housing a program supported by a donor, have the donor’s name appearing on each door, Mr. LeClerc said.

The Schwarzman engraving design was executed by the renowned design firm Pentagram at the behest of the New York Public Library, and will be executed by a stone carver yet to be selected. The plan was approved Tuesday by the Landmarks Preservation Commission.

Mr. Schwarzman, a trustee of the library, was not at the meetings of the board during which deliberations were held about placing his name on the façade, but he was informed of the plans before they were brought before the landmarks commission, Mr. LeClerc said. Mr. Schwarzman has said that he did not stipulate that his name appear in such fashion in his own discussions with the library about the gift.

Will Mr. Schwarzman’s name become associated with the New York Public Library in the same way that say, Andrew Carnegie is associated with the libraries he helped build across the country? “It’s unlikely. Carnegie gave 2,000 libraries, for goodness sake,” a biographer of Carnegie, David Nasaw, said. “They’ll probably keep on referring to it as they always have, as the New York Public Library. How many people think about William Shea when they go to Shea Stadium?”