Checks if the PDF document contains any pages that already have been separated.
A pre-separated PDF contains pages that have been separated into their CMYK components. In offset printing each of these colors is printed with a separate plate. This means that each page in a PDF document is separated into its four constituent colors: cyan, magenta, yellow and black. For example, a pre-separated PDF file for a two-page CMYK print job, results in a PDF file with 8 pages.
This separation process is usually carried out by the RIP, and not in the source PDF document.