During his visit to the 47 Ronin set at Pinewood Studios on June 7, Steve Weintraub talked to costume designer Penny Rose. She talked about assigning specific colors of costumes to various characters so they would be easily trackable during fight sequences. She also talked about designing costumes for 3D and working with CGI characters. In total there were 998 costumes and 400 suits of armor made for the film.
The interview is a good read and can be viewed here.