I'm getting Aperture 2 soon but I'm slightly confused about how stacks work. When I import a RAW image into the Aperture library, that is the master - am I correct? but when I duplicate it, does it make another stack or is the duplicated RAW image stacked under the master. Or do they both become masters (like two completely different images?) Also when I adjust a RAW image (brightness, highlights, etc.) and save the file, is it saved as a version under the master of the stack? this is all very confusing!! basically what is saved as a version and what is saved as a completely different master?