Essence, a nationally circulated black women's magazine, aired a "family secret" in its July issue. It is how differing hues of skin color come between blacks and make some still live in a separation of shades.

The magazine had run a cover on the April l982 issue showing a blue-eyed black woman, and readers wrote in irate because one out of 143 Essence covers had dared to feature a black woman with blue eyes. It seems the criticisms ran along the lines of, "To me this symbolizes that black people are trying to be white" or, "Since the real black woman . . . is not your idea of beauty . . . . "

In letting the skeleton out of the closet this month, the magazine wrote: " . . . Color still affects our thoughts, attitudes and perceptions about beauty and intelligence, about worth and self-esteem." The question was examined in articles from the perspectives of a dark-skinned black woman and a light-skinned black woman, and from the historical perspective by the noted novelist Alice Walker.

I think these articles indicate a certain black coming of age. They are a healthy sign, a turning point in the way blacks think about one another.

In the past, blacks didn't want to talk about such things openly. It has been hard to admit to the wider world that some blacks felt that way about one another even if the socialization in America was such that it was hard not to feel that way. For centuries, white America projected the imagery of beauty and power as white, and the imagery of shame and degradation as black.

Blacks knew that the symbolism of white was as distorted as the symbolism of black, but saw society's rewards often bestowed on the basis of the distorted symbols. Even the novels of 19th century black authors abounded with light-skinned black women. Walker explains why:

"Most readers of novels in the 19th century were white people; white people who then, as more often than not now, could only identify human feeling, humaneness, if it came in a white or near-white body, and because although black men could be depicted as literally black and still be considered men . . . . the black-skinned woman, being dark and female, had to be whitened, since 'fairness' was and is the standard of Euro-American femininity." It would be the l920s and 30s before black women novelists began painting black women naturally in all the colors in which they exist.

But life did not so readily imitate art, and many blacks bought into prizing the light-skinned black woman above the blacker-skinned black woman. Some blacks did this in spite of overt racism and perpetuated what amounts to a caste system--the folks E. Franklin Frazier wrote about in "The Black Bourgeoise."

The l960s revolution of black consciousness, when many blacks overthrew the rule of white men in their minds, freed many black-black women from this stereotype and gave them a way to love themselves. But this psychological revolution hurt some light-skinned black women who found themselves criticized as "not black enough."

As the pendulum swung more to the middle in the last 15 years, there were still women at either end of the spectrum. There were still dark-skinned women who felt lingering discomforts about discrimination against them, and light women who either were color-struck or who chafed because darker women still felt that they gained advantages from being light. The issue was largely underground. Maybe groups of light- and dark-skinned women talking among themselves, but not to each other.

Some blacks didn't want white people to know how they felt about this schism of color. But this attitude is a form of entrapment that is little more than worrying about what other people think.

Many women perceived these feelings as shameful and irrational and found the pain and conflict depressing. And the very act of the cover-up wasn't normal.

So when Essence dared to put a blue-eyed woman on its cover, the howl of protest from dark-skinned black women was a primal scream that bared the war they were still having within themselves.

The fact that the subject is being talked about openly is a healthy sign, for we can't act upon a destructive attitude unless we face up to it. And the truth is, light-skinned and dark-skinned blacks have sometimes been cut off from each other.

But these stories could be part of the revolution that ultimately will make blacks more respectful of themselves and everyone else. And that can't be anything but good.