The Landmarks Preservation Commission held a hearing this morning on the second revision of plans by Aby Rosen to enlarge the low-rise building that occupies the west blockfront on Madison Avenue between 76th and 77th Streets.

The new plan is quite similar to the first revision that was submitted last year except that the facade color of the addition will now be silvery rather than champagne. Both "as-of-right" proposals were significantly downscaled from Mr. Rosen's initial proposal, designed by Sir Norman Foster, that called for a reflective-glass, curved tower to rise 22-stories above the northern end of the existing building with the remainder of the existing building's large roof being converted to a sculpture garden.

All of the proposals would restore the existing 5-story, limestone-clad building designed in 1950 by Walker & Poor to house the Parke-Bernet Auction House, that was later bought by Sotheby's, and a Schrafft's restaurant. The building had been modified several times.

The commission did not vote on the first design offered by Mr. Rosen and his architect, Sir Norman Foster, who has also designed the revised plans. The first and second revisions would contain about 18 condominium apartments.

Whereas the first design did not comply with existing zoning and building regulations, the first and second revisions do and only require approval from the landmarks commission because it falls within an historic district.

The facade of the addition in the revised designs is very unusual and consists of a "veil" of thin horizontal strips several feet in front of glazing. Many of the strips can open as shutters at a 90-degree angle and then several of them can be moved, like an accordion, to one side to create a quite broad opening.

Brandon Haw of the Foster + Partners office said at a previous hearing that this part of the facade of the addition will add "a mysterious feeling" and would be a "contemporary" addition to the "elegance" of the Upper East Side.

Lord Foster is also designing a mixed-use tower for Mr. Rosen at 610 Lexington Avenue.

Commissioner Steven Byrnes said that the restoration of the former Parke-Bernet Building is "very important" and said that the current plan "overwhelms" it. He suggested that the "addition" should be recessed and have only two full floors and then one more setback from them and possibly one more setback even further.

Commissioner Margery Perlmutter said that the new plan "is a good piece of architecture" and was "elegant."

Pablo E. Vengoechea, the commission's vice chair, said he would like to see a better "transition" between the old and new sections of the project, adding that while he had no problem with the previous color the new plan was "very top heavy." Furthermore, he suggested that the developer should "eliminate the artificial recess" in the center of the avenue frontage of the addition so that the addition would become more "abstract." Mr. Haw, however, had explained that the "recess" was mandated by the site's zoning.

Commissioner Joan Gerner said that the plan's materials were "exquisite" and that "the only problem is that it is too high" and that she could "support three stories with a setback."

Commissioner Diane Chapin said that the addition should have its own character to serve as a counterpoint.

Robert B. Tierney, the commission chair, described the revised plan as "brilliant," but urged the applicant to consider the commissioners' concern about reduction in scale and no vote was taken.

Mr. Rosen, who is an owner of Lever House and the Seagram Building, two of the city's most famous world-class modern landmarks, told CityRealty.com after the hearing today that he will "consider" returning to the commission with a design that takes into account many of the commissioners' comments.