AFTER YEARS of insisting that the public wants bright, colorful stamps, the Postal Service has issued a stamp that breaks all the rules -- and it's certain to be a bestseller.

The first "makeup" rate stamp, which went on sale Tuesday along with the F stamp, is a design dud, a horrid-looking stamp that doesn't even, well, look like a stamp.

It lacks everything the Postal Service has said a stamp ought to have: an attractive, vivid design, a minimum of text and a familiar format. The stamp, which sells for four cents, is being sold for use with existing stocks of 25-cent stamps to "make up" the difference between the current 25-cent first-class letter rate and the 29-cent rate, which becomes effective Feb. 3.

But with its pale white background, red lettering inside a gold border, 16 words of text and lack of a denomination, the makeup stamp seems more like a label than a postage stamp.

Postal spokesman Jim Murphy said it was a case of function over design.

"This stamp has to serve a real basic purpose. It had to serve an educational purpose," he said, noting that the Postal Service had never issued such a stamp. In the past, existing stocks of 1-, 2-, or 3-cent stamps were deemed adequate to cope with any change.

The makeup stamp's wording -- "This stamp, along with 25

of additional U.S. postage, is equivalent to the 'F' stamp rate" -- states its purpose precisely.

"We didn't believe it needed to have a design and I don't know what that design could have been," said Murphy. As a result, there was no debate over how the stamp should look, he said, something that should make the stamp, printed by the American Bank Note Co., unique.

Because of the stamp's unusual appearance, Murphy said that the Postal Service will begin an internal campaign to make certain its employees recognize them as valid.

The makeup stamp was one of four rate-change stamps that went on sale Tuesday after the Postal Service Board of Governors voted to accept the new rate structure. Also released were the long-expected F stamp bearing the image of a red tulip, an official mail F stamp for government agencies, a new plastic flag stamp that will be sold through automatic teller machines and a new official mail F-stamped envelope.

In what is another first, the tulip stamp was printed by three different printers, a decision that is certain to produce a number of varieties of the stamp. American Bank Note produced sheet versions of the stamp, the Bureau of Engraving and Printing printed booklets of 10 and 20, and coils of 100, 500 and 3,000, and KCS Industries Inc. of Milwaukee also produced booklets of 10. The latter booklets are the first printed by one of the subsidiaries of Banta Corp., a Wisconsin firm which last year won a $5.3 million booklet contract.

The F stamp, which the service prefers to call the "flower stamp," was designed by Wallace Marosek of Boston and features a close-up of a single red tulip set against a yellow background. It carries a large letter "F" and the word "Flower" above the lettering "USA" and, unlike the five previous letter stamps in the non-denominated series, bears the warning the stamp is "For U.S. addresses only."

Under international regulations, all stamps used on international mail are required to carry a precise value. Officials say that the warning should prevent a reoccurence of what happened in 1988 when many letters that carried the E stamp, issued for the last rate change, were rejected.

The only difference between the design of the new official mail stamp, official mail envelope and the plastic stamp and that of the previously issued versions of those items is that the new versions carry a large F instead of a 25-cent denomination. All are likely to be replaced later in the year by stamps bearing a 29-cent value.

Meanwhile, Linn's Stamp News reports that the service already has planned the next rate-change stamp, a G stamp that will carry the image of the flag "Old Glory."

THE NORTHERN Virginia Coin Club holds its quarterly show at the Vienna Community Center, 120 Cherry St. SE in Vienna, from 10 to 7 Saturday and 10 to 5 Sunday. Admission is free.

Bill McAllister is a member of The Washington Post national staff.