print production - InDesign: how to mark lines for printing cuts?

How can I insert printing marks to designate a smaller format than the page size? Printing shop insists that for making a 7x5 inch print they need me to insert it into an A5 document. So placed it as they said, but am a bit uncertain how I could mark for them where the paper needs to be cut.

Answer

• Add a new Swatch (any color) and make it a 'Spot' color.


• Draw a 7x5 inch rectangle in the middle of the A5 sheet and stroke it with this new swatch.


• Set the rectangle stroke to 'Overprint' via the 'Attributes' panel.


• Place your artwork inside the rectangle.


• Export to PDF.