PDF/x is subset of a standard PDF specifically created for the prepress environment.

For example, PDF/x applies restrictions such as that all fonts must be embedded, colors must be CMYK or spot, it cannot be encrypted, it must not contain any type of not printable objects etc.

Moreover, a PDF/x file contains additional information, e.g. a flag which indicates that the PDF file is a PDF/x and which flavor of it.

GN4 prior to 2.5 creates a PDF/x compatible format but it doesn't set the PDF/x flag.

This will be available when GN4 would support the Adobe PDF Library version 15 (currently we are using version 10).

See also

PDF versions produced by GN4