On Fri, Dec 20, 2019 at 11:00 AM Peter Rolf <indiego@gmx.net> wrote:
Hi Hraban,
PDF/X-1a:2001 doesn't support transparency. You have to use PDF/X-4(p)
for that (the first X variant that supports transparency).
PDF/A-2|3 may also be an option. These formats also support transparency.