Command should be purple. If it was good enough for the Romans, it's good enough for Starfleet.
Although iirc what they called "purple" is supposed to be more like our blood red...![]()
Apparently one of the reasons that the specific dye was prized was that it's color actually improved with age. The money quote on this comes from Pliny the Elder in his Natural History
The Tyrian hue ... is considered of the best quality when it has exactly the colour of clotted blood, and is of a blackish hue to the sight, but of a shining appearance when held up to the light; hence it is that we find Homer speaking of "purple blood"