A decision by Macy's to require all employees to wear black has a lot of workers at the Downtown department store seeing red.

The union that represents workers at the former Kaufmann's flagship has filed a grievance to rescind the new dress code, which goes into effect Sept. 4 for about 17,600 workers at all 113 Macy's stores in the nine-state Midwest division.

The beef illustrates the drama that can ensue when employer fashion edicts clash with personal style and become an additional cost to employees. In 2003, for example, Abercrombie & Fitch agreed to pay $2.2 million to settle a lawsuit over allegations that the youth-oriented apparel retailer forced California workers to buy and wear its clothes on the job.

While Macy's won't be forcing its employees to shop at the department store, it is offering a "deep discount" to workers to help them blacken up their wardrobes, said Macy's Midwest spokesman Nathan Shore.

The dress code, already in effect at most other Macy's divisions, is intended to make it easier for customers to identify store employees, Mr. Shore said, adding: "It also looks great."

The new guidelines require workers to wear black tops and bottoms or black dresses. Blouses, shirts and neckties can be any color with a black suit. Shoe and accessories colors remain the employee's individual choice.

Employee response to a black dress code in other divisions has been positive, Mr. Shore said. He noted the chain always has required professional attire; the only thing that has changed is that it is now requiring a specific color.

"It takes the guess work out of getting ready for work,'' he said. "They can still express their individuality through shoes and accessories."

Thomas R. Scheid, a union representative for the Pittsburgh office of the Retail, Wholesale Department Store Union, doesn't see it that way.

He said the dress-code policy violates a contract provision and the National Labor Relations Act. The union has represented workers at the Downtown store since it was Kaufmann's, prior to changing its name to Macy's last year after Kaufmann's former parent was bought out by the Cincinnati-based retailer.

In a July 9 grievance letter to Kim Bass, Macy's Midwest manager of labor relations, Mr. Scheid wrote that the new dress code "will result in significant out-of-pocket expense to members of Local 101." He said he hopes to resolve the issue at a meeting with management tentatively scheduled for next week.

The new policy would give Macy's the strictest dress code of any department store in the region. Not even upscale retailer Saks Fifth Avenue, a block away from the Downtown Macy's, has such a rigid code.

Saks employees, surrounded by luxury goods and apparel, are asked to be "fashionable yet professional," said general manager Karen Peter, who has observed the relaxation over time of dress codes in U.S. retail stores.

One exception at Saks is the Louis Vuitton shop, where workers are furnished chic suits that they are required to wear, said Ms. Peter.

The black dress code at Macy's is part of the store's strategy to better serve customers, said Mr. Shore. He said customer response to the code in other divisions has been positive.

"Customers are sharing that it's easier to spot associates in the store. They've also commented that it looks very fashionable."

As she left the Downtown Macy's yesterday afternoon, customer Sylvia Robinson said she would rather see colorful employee name tags than workers arrayed in black. She called the dress black code "a little ridiculous."

"They should wear what represents the store," said Ms. Robinson, 42. "The trends are color. The store doesn't sell all black. If you want somebody, women, to shop there, that's not going to appeal to them."