Rick Berman insisted on a new uniform for Deep Space Nine, rejecting budget-conscious overtures from Producer David Livingston, who had suggested using the same costumes as The Next Generation to save money.
It fell on Robert Blackman, who had been in charge of costume design since Season 3 of The Next Generation, to come up with uniforms that looked different enough to set the new show apart, but similar enough that the two could reasonably coexist in the same universe.
Blackman felt that, for a space station, the uniforms should be more utilitarian. The Next Generation’s had a “very dignified and ennobling kind of appearance,” he told Cinefantastique in 1996, “with that vertical, perfectly done, military-esque kind of structure.”
Deep Space Nine’s, by contrast, were “a cross between a NASA jumpsuit and a mechanic’s jumpsuit.” They were looser and they allowed characters to roll up their sleeves, something Chief O’Brien (Colm Meaney) would often do.
Blackman toyed with making the uniforms out of cotton twill, but chose wool after making some test suits. Cotton doesn’t dye as permanently. The colors would have fainted with repeated washings.
“Wool is actually a wonderful, breathable fabric,” he said.
They’re not lined very much. They have some structure built in, but not much. They’re soft-shouldered.
The result was a uniform that Blackman felt looked more real.
You and I could put on one of those suits and walk around. They’re still very handsome, but there’s great mobility and a lived-in reality to them.