Things were looking bright and shiny and homogeneous on Central Park North and Malcolm X Boulevard on a recent Sunday.

A new 19-story blue-glass condo caught the summer sun, shimmering with wealth and comfort. On the fifth floor, a white man pointed from his gleaming balcony, apparently enjoying his commanding view of Central Park's undulating meadows. Several other residents, who all also appeared to be white, gazed out serenely from their own balconies. On the sidewalk, a white couple sat beneath a white market umbrella as clean-cut white pedestrians strolled past.

If something seems wrong with this picture, that's because a picture is all the scene was — a large artist's rendering, posted at the construction site at 111 Central Park North, where the condo will soon rise.

But the decidedly bleached vision of that corner has not gone unnoticed in the area, which is mostly black and Latino and which has seen less of the striking gentrification that has swept across many other parts of Harlem.

"People stop here and say, 'Do you see one black face?' " said Fatimahta Adegoke, an energetic woman with dreadlocks who was selling African soap nearby.

Ms. Adegoke jabbed a painted fingernail at the condo's billboard, which advertised apartments of $1.5 million and up. The median family income in the Central Park North area, which is south of 116th Street from Frederick Douglass Boulevard to Fifth Avenue, was $24,000 in 1999.

"If it's starting at $1.5 million, they're blatantly saying, 'We don't want black folks or people of color around here,' " said Ms. Adegoke, who lives in one of two homeless shelters on Central Park North, also known as 110th Street.

Bill Perkins, a former city councilman for the area who is running for State Senate, said that local outrage at the rendering was so great that he had threatened the building's developer, the Athena Group, with demonstrations if the image was not removed. The controversy was first reported in The Amsterdam News.

"It's the nightmare, in your face, of what people fear is happening to their community," Mr. Perkins said. "At the doorway to a historic, world-renowned black community, there's an all-white message."

In response, Kenya Smith, the Athena Group's vice president of development, said that the rendering would be altered to include more people who are clearly African-American. Mr. Smith said the figures in the rendering were merely included for scale.

"It's not an attempt to keep anybody out," he said. "We want as inclusive a building as anywhere."

For some longtime residents, however, the image seemed an all-too-literal representation of their anxieties about gentrification. About six years ago, only about 3 percent of the area's residents were white, according to Census figures, but real estate brokers and residents say the percentage, including many Europeans, has surged since then.

"They're moving us out," said Keith White, a 26-year-old African-American with a glittering stud earring, who was buying a cherry ice from a Mexican vendor beneath the condo site's scaffolding.

"Now the rent is going to go up more," added the vendor, Melissa Santos. "So now everyone is going to live in the Bronx."

Even without such mass displacement, central Harlem's demographic shift is already transforming the area's street life. On Central Park North, residents say, the number of men with gray Afros who socialize outside rental buildings has diminished, while No. 217, a mix of rent-stabilized and market-rate apartments, will get a doorman starting this week. Central Park North is now a street of stark contrasts, where black and white professionals carry their dry cleaning past the sealed windows of the Lincoln Correctional Facility, while apartment owners at the Semiramis, a granite-columned prewar condo, complain of the homeless trying to sneak into the building.

The new glass tower will add a luxe element, which some middle-class blacks welcome.

"It'll clean up the neighborhood a little bit," said Earl Wint, 47, a baby-faced Jamaican-American film production assistant who was playing dominoes with friends on 111th Street.

Others were less sanguine about any accelerated influx of white residents. "When I see a lot of other white people," said Jamie Black, a white editor at a Jewish service organization who is a 10-year Harlem resident, "I think, 'There goes the neighborhood.'"