Acrobat allow us to define a new cropping for a PDF using the Advanced Editing  > Crop Tool, or precisely with the help of the Advanced > Print Production > Crop Pages dialog [Cmd+Shift+T (Mac) /Ctl+Shift+T (Win)]. It works fine, but it does not delete the cropped elements from inside the PDF, there are just hidden. Another problem you might have encounter is that when processed on your RIP, the rendered images is not the one you have cropped but the original at full size. Does that mean the Crop tool is only useful when viewed inside Acrobat? Is there a way to fix that? Read the article