You used PAL as a source, which has a bit better color timing than the NTSC version. So thus, when you converted PAL to NTSC (which is what you did, right?) it preserved the better image coloring. The Death Star goes from blackish blue (NTSC) to the correct grey (PAL).
Really? That's odd, since the region 1 and 2 DVDs would probably have been mastered from the same source... weird!
DE