The Montgomery County NAACP has taken a look at the boards of 142 Washington-area business corporations. The surprise is not merely in what they found but also in the fact that hardly anyone had bothered to look before.

What they found is this: of the 1,416 board seats involved, 19 were held by black men, 6 by black women and 51 by white women. Don't bother figuring the percentages. They'll only dismay you.

But they will surprise you only if it never occurred to you before to think about "Racism & Sexism in the Corporate Boardroom," which is what the NAACP chapter calls the report it issued Saturday. To think about it is to be reminded that where real economic power is, blacks and women generally aren't.

There are exceptions. One specifically commended in the report prepared by Leroy W. Warren Jr. is the Gannett Co., Inc., whose 17 board members include a black man, a white woman and two black women. Gray & Co. has four women on its 14-member board, but no blacks.

Listed at the other extreme were 124 companies with no black directors at all, and 100 with no women. Two were singled out for special mention: the Hechinger Co., which the report said had "a large base of black customers," a "progressive" president (John Hechinger) and not a single black board member; and The Washington Post, "a national and international leader in the field of human rights," with, according to the survey, no blacks and a single woman: Katharine Graham, president.

When told that the Hechinger Co. and The Post had both named black women to their boards in recent months, Roscoe Nix, head of the Montgomery NAACP, said he was "delighted" to make the additions. "We might have missed a few more -- some companies didn't respond to our repeated requests for information, and we had to go to the Securities and Exchange Commission records. But even if we doubled the percentage for women and raised the numbers for blacks by 500 percent, blacks are still being robbed."

Nix and Warren, the report's author, attributed the dearth of black and female directors to "racism" and "sexism."

The truth may be simpler than that, though hardly much more reassuring. I suspect that a good deal of the problem stems not from bigotry nor even from the absence of "qualified" prospects but from the fact that white men in power seldom think about the absence of black and female directors at all, let alone think of it as a problem to be addressed.

And when they do, they are apt to launch a search for black and female superstars. A glance at the board lists released Saturday suggests that a good many of the white male directors fall somewhat shy of superstar status.

As Warren put it, white men in power tend to appoint "people they know, people in their clubs, people they play golf with. If they can't find any (blacks or women) it's because they are blind."

Or will not see. When the dearth of blacks and women executives surfaced as an issue, companies turned to executive search agencies -- "headhunters," as they are called. The question of board memberships was never really raised as a public issue before now, and, as a result, has not been seriously addressed by the corporations.

But directors, while principally chosen for their business and financial acumen, also set corporate policy on matters that affect the broader community. The absence of blacks and women among these policy makers does not guarantee that the policies will be racist or sexist, but it does increase the likelihood of racist or sexist results, if only through inadvertence and inattention.

Washington-area businesses have reason to be embarrassed by the survey, which echoes a new national policy of the NAACP. With any luck at all, they will react not with defensiveness but with a vigorous effort to tackle this serious problem.

And if they need help, either in focusing on the problem or in resolving it, the NAACP says it's ready and eager to help.