As the unofficial office summer tan judge (my expertise is derived from being born tan), I am frequently asked by those returning from vacations to rate their skin tone.

"Look, I'm darker than you!" some say excitedly.

"Uh, could you hold out your arm," say others. "I just want to check something."

Sure thing, pal. I just wish I had some "Honorary Negro" buttons to pass out. I enjoy this summer sideline; never thought I'd see the day when browner was better. But tanning is in, folks. Dare I ask why?

During these last weeks of summer, sunbathers quilt area beaches with complexions spanning the skin-tone spectrum, including black, burnt pink and fire-engine red. Laid out, bellies up, they are engaged in a modern form of sun worship where self is sacrificed instead of virgins.

There are countless sunning systems, including the latest Solana Sun Beds, featured at the Sun Club near Dupont Circle, in which tanners can hop into a glass bed--naked--and bake like a Frank Perdue oven roaster. There are lotions, potions, oils, creams and screens for quick tans and slow fades.

Never mind that about 3,500 persons die from skin cancer each year while countless others suffer heat strokes and dehydration. The risks are well known, but apparently worth taking in pursuit of that perfect tan.

So why, folks?

"I want to be a sort of olive brown," says one woman as she fries her face off at the "beach" at Wild World. "I have a white jump suit that I can't wait to wear." Judging from her overexposure, she may have to wait until next summer or at least find an outfit in say, black.

Over in Lafayette Park, a government type has taken his shirt off and stretched out on a bench. Sunburned and drenched with sweat, he puts his shirt back on and struts back to his office as if he were wearing a red badge of courage.

"My girl thinks my 'tan line' is sexy," he says, wiping grease from his girth. Some taste.

For some reason, people associate a glowing tan with good health. A smooth caramel color, if acquired, supposedly suggests that one has been energized by nature's most powerful force.

Actually, working for a tan--as practiced here--is a relatively new phenomenon.

Historically, a dark skin has always had social significance. Older cultures regarded tanning and weathering of the skin by sunlight as stigmata of the lower classes. The pale translucent complexion was most desired. Tans identified a person as laboring in fields.

Then came the industrial revolution, moving the lower classes indoors.

"Increased leisure has altered the attitudes towards outside activity," says Dr. William Becker, a professor of dermatology at the University of Illinois. "Many segments of current American society endow a deep tan, especially out of season, with an aura of virility, leisure and wealth."

Then again, there are other interpretations of what may be going on.

In his book, "Black Like Me," John Griffith, a white man who took drugs to turn black temporarily, said of his experiences, "I am constantly approached by whites in the U.S. and Africa who want the experience of being black."

Says Dr. Thomas Williams, chief of dermatology at Howard University:

"You have whites who want a tan because they say it makes them look good and you have blacks using skin lighteners and hair curlers because they say that makes them look good. I see this as diabolically funny."

The implications could be far-reaching, suggesting a change--if not a decline--in the significance of skin color. It would be nice to think that all this is leading toward a more equal view of all colors, all year round.

Meanwhile, my vacation-bound colleagues are still coming by for skin spot checks. I encourage them to go for it, reminding them what the old folk in my neighborhood used to say about the matter: "The blacker the berry, the sweeter the juice."

I can't wait for them to return. I can hear myself now, "And the winner of this summer's Al Jolson Award is . . ."