I was given a project re-creating and correcting display Ads for newspapers and magazines. The client supplied Quark layouts with rasters missing (of course). They did include the resulting PDF/x1-a files with all the rasters embedded. I know how to extract the rasters and my question is can I re-use the extracted rasters, does embedding and extracting cause any issues? If so, can I color correct them if needed-I will be setting black point, white point and mid-tones for newsprint? I will be re-embedding the rasters in new pdf/x1-a.