Who can tell me how to add corner lines to every same page in PDF?

As shown in the figure, it is a prepress output file generated by RIP software. Generally, it is not a PDF format, but a bitmap. The alignment mark on the corner is the process line in the color printing process, and the RIP process can be automatically generated without adding it to the PDF file. 100 page book is difficult to see all the color pages, monochrome pages do not need to be aligned, and the alignment lines are completely redundant.

The corner alignment mark line is generally cut off in printed matter, so it cannot be seen. If you pay attention, you can also see the alignment mark at the middle seam of the newspaper color page.

Common RIP software, domestic Peking University Founder PSPNT, foreign HQRIP, also has Chinese version. RIP can also generate PDF files with alignment marks that you want, but they are all dot matrix and not vectorized. It is easy to add corner lines to black and white pages, as long as you are not afraid of being laughed at.