Suppose that some of the PDF documents you work with contain RGB colors. First, you want to print them on a composite output device, such as a laser printer, for proofing purposes. In that case, RGB colors are not really a problem. However, you would like to know which PDF documents contain objects in RGB color, because at a later stage, you might want to print these documents on an offset press. You could then use two different Preflight Profiles to preflight these PDF documents: