The Blu-ray does not have accurate colors. That said, if it shows such a marked difference at a specific location, likely there was a difference in paint on the set. Determining what those colors were is problematic.

Also, it is more accurate to scan a source such as that book photo of the imperial uniforms on a flat bed scanner. Cameras tend to adjust white balance based on various factors and don’t lead to accurate colors in the photo. Even flatbed scanners have issues but they are generally more accurate and can be calibrated. Also it would depend on when the photo was taken and what condition the costume was stored under. Fabric colors and change as they age.