Black may be capitalized when used in reference to people, as a sign of respect. The case for capitalizing the initial letter ( Black ) is further supported by the fact that the names of many other ethnic groups and nationalities use initial capital letters, e.g., Hispanic.
Black as an adjective referring to a person or people is unlikely to cause negative reactions. As a noun, however, it does often offend. The use of the plural noun without an article is somewhat more accepted (home ownership among Blacks ); however, the plural noun with an article is more likely to offend (political issues affecting the Blacks ), and the singular noun is especially likely to offend (The small business proprietor is a Black ). Use the adjective instead: Black homeowners, Black voters, a Black business proprietor.
In the United States, there is a complex social history for words that name or describe the dark-skinned peoples of sub-Saharan Africa and their descendants. A term that was once acceptable may now be offensive, and one that was once offensive may now be acceptable. Colored, for example, first used in colonial North America, was an appropriate referential term until the 1920s, when it was supplanted by Negro. Now colored is perceived not only as old-fashioned but offensive. It survives primarily in the name of the National Association for the Advancement of Colored People (NAACP), an organization formed when the word was not considered derogatory. Describing someone as a person of color, however, is not usually offensive. That term, an inclusive one that can refer to anyone who is not white, is frequently used by members of the Black community. Using “of color” can emphasize commonalities in nonwhite lives. However, when referring to a group of people who are all Black, it is more appropriate to be specific. Failure to explicitly reference blackness when it is exclusively appropriate, generalizing “Black” to “of color,” can be a form of erasure.
Negro remained the overwhelming term of choice until the mid-1960s. That decade saw a burgeoning civil rights movement, which furthered a sense that Negro was contaminated by its long association with discrimination as well as its closeness to the disparaging and deeply offensive N-word. The emergence of the Black Power movement fostered the emergence of Black as a primary descriptive term, as in “Black pride.” By the mid-1970s Black had become common within and outside the Black community. But Negro has not entirely disappeared. It remains in the names of such organizations as the United Negro College Fund, people still refer to Negro spirituals, and some older Black people continue to identify with the term they have known since childhood. So Negro , while not offensive in established or historical contexts, is now looked upon in contemporary speech and writing as not only antiquated but highly likely to offend.
During the 1980s, many Americans sought to display pride in their immigrant origins. Linguistically, this brought about a brief period of short-form hyphenated designations, like Italo-Americans and Greco-Americans. The Black community also embraced the existing term Afro-American, a label that emphasized geographical or ethnic heritage over skin color. The related label, African American, also saw an increase in use among activists in the 1970s and 1980s. African American was even more widely adopted in the late 1980s and throughout the 1990s after high-profile Black leaders advocated for it, arguing, as Jesse Jackson did, that the term brought “proper historical context” and had “cultural integrity.” While African American has not completely replaced Black in common parlance, it works both as a noun and as an adjective.
This shifting from term to term has not been smooth or linear, and periods of change like the late 1960s were often marked by confusion as to which term was appropriate. The 1967 groundbreaking film Guess Who's Coming to Dinner, about a young interracial couple hoping that both sets of parents will accept their plans to marry, reflects the abundance of terminological choices available at the time. Various characters talk of a “colored girl,” a “colored man,” a “Negro,” and “Black people.” The N-word appears once, used disparagingly by one Black character to another. African American had not yet made it into the mix.

Did you mean blackness?