At the corner of Linden Avenue and Ducatel Street -- once called Dodge City in honor of the many shootings there -- they call him The Picture Man.
At 67, his graying hair in dreadlocks, Mr. Clark is a highly regarded and widely exhibited photographer whose work affirms the humanity of inner-city African-Americans whose lives approach invisibility.
His work is a weighty counterbalance to so much of American culture, in which black people don't exist unless they're athletes, entertainers or drug dealers.
His photos bring dignity and acknowledgement to the ordinary, even the mundane aspects of African-American existence in Baltimore.
Thus his artistic focus falls somewhere between Ralph Ellison's novel, "Invisible Man," and the poem "My People" by Langston Hughes. The Hughes verses ("The night is beautiful/ So the faces of my people...") are pasted on the inside of his glass front door on Linden Avenue.
The faces are celebrated in the images on the walls of the photographer's living room, framed and stacked inside the front hall, piled on bookshelves and, now, on display at the Brooklyn Museum of Art.
Recurrently suicidal long after tours in the killing fields of Korea and Vietnam, Mr. Clark saw ending his life as escape from the torment. Even now, he begins each day with a desperate self-urging: "Hold it. Hold it," he commands himself upon waking until he remembers his life has meaning he can believe in.
Certain he was insane and oddly pleased to be so -- sane people who kill are murderers, he says -- art suddenly made him a giver and not a taker of life. He thinks others will be able to see and follow his path.
The gifts of black Americans, he says, have been creative and yet in poor environments people necessarily focus on the concrete: jobs, food, safety. They can't afford to dream and when they are ignored, their humanity comes into question.
Without self-image there is no self, no identity, no place or purpose. Through the discerning lenses of his camera and his life, he tries to supply what is missing: an imagery of self and community that reflects substance back to those who may have doubted their place in the world.
What he does demands an interplay between willing subjects who release their essence, whose expressions and postures declare the meaning of their lives. His pictures define pride, independence, loneliness, beauty, pain and defiance, never surrender.
In warm weather, he sits on his marble steps taking Polaroids of neighbors who've never been photographed, who have no family albums, some of whom wonder why he would want to photograph them.
He has done series of pictures showing women in flamboyant hats; people in the haunting confines of subways; children at play; and young black men in street-corner society.
Disbelief greeted him often. "Your pictures are just like Life magazine," a woman told him, "except the people are black."
His artistic universe extends to Nigeria, where he recently spent two months, but more immediately just down Linden to North Avenue, which he calls a place of pure beauty.
He flips through a portfolio of images he recorded in Baltimore and stops, arrested once again by a man in a ragged straw hat.
"I love his eyes," he says. That love glows in every face and frame.