Clothing
The Roman Army never had what we would consider to be a uniform. In our period, military manuals do make recommendations as to main garments and footwear, but purely on the basis of greatest practicality, with no mention of details like colour.
A basic reference is the Levantia (offsite link in new window) website created by our patron, Dr. Timothy Dawson. In the army connection especially the men’s clothing and military pages (both kinks will load into this site, by permission).