How to add printer marks and bleeds to PDF documents

 Author:   Posted on:   Updated on:  -
In a previous article I showed you how to add headers, footers and/or watermark to PDF documents using free software running on Linux. But that method doesn't work for bleeds and printer marks because these are supposed to be outside the page dimensions. And when overlaying two PDF documents with pdftk, it automatically resizes their pages to match. What is about to follow, is similar to the mentioned article, yet there is one important additional thing to do: increase the page size of the source PDF before adding the bleeds layer over it.

This tutorial has been made on Linux, yet the tools that I'm gonna use are cross-platform and free, so you can try it on other operating systems too. In short, to add printer marks and bleeds to a PDF document, you should generate a marks and bleeds only PDF for the source document page size, then increase pages size of the source document and at last overlay the marks and bleeds document.

How to add printer marks and bleeds to PDF documents
Before starting, let's install required software. We'll need Scribus, pdftk and the pdfcrop utility from TexLive. You can install these on Ubuntu Linux using this command:
sudo apt-get install scribus pdftk pdfchain texlive-extra-utils
I suppose you already have installed a PDF viewer that can tell you the page dimension of a document. By the way, this how-to is intended for PDF documents with constant page size. Here is how Evince displays page size:

PDF page size evince
PDF page size
Now there are many ways to do it. In my example, the page size is 216 x 279 mm, so all I have to do is design the marks and bleeds page in LibreOffice Draw, GIMP or Inkscape. To do that, first choose the height/width of the marks in order to know what size will be the marks page. For example, If I want 10 mm marks on all margins, I would make a document (image) with the size of 236 x 299 mm (added 2 x 10 mm to each). Then I would use pdfcrop to increase the size of my source document to the size of the marks document and overlay the latter using pdftk.

I will show you a simpler method that involves Scribus. Why this? Because Scribus can add printer marks to a document. So, launch it and make a new document of one page with the size of the source PDF document! That's 216 x 279 in my case. Scribus knows to add printer marks outside of the page.

Scribus new document
Make the new document in Scribus
All you have to do now, is export this document to PDF (you could save the document with a chosen name, because its name may appear below the printer marks). Don't add anything on the page! Just click the Export to PDF button and don't forget to set printer marks from the Pre-Press tab. Check whatever you want.

Scribus marks and bleeds settings
Marks and bleeds settings
If you don't want page numbering, uncheck Page Information. If you want it however, you should have made a Scribus document with the exact number of pages as the source document. This is similar to adding page numbers to PDF which is described in a previous article.

It's time to check the result page size and do some calculations. Mine has 230 x 293 mm, so the marks take up (230 - 216)/2 = (293 - 279)/2 = 7 mm. I have to match the source document page size to this, so I should add a margin of 7 mm on all sides. Here comes handy pdfcrop. It would have been easier to use if it accepted metric inputs. This is an utility intended to autocrop PDF pages and it has the option to add some extra margins to the cropped result. To use it for the purpose of solely increasing page size, we must specify that the bounding box is equal to the page size, so it won't crop the page. It uses bp units, which represent pixels at 72 PPI. My source document size is 216 x 279 mm. To convert to bp, I do the following: (216 mm / 25.4 mm) x 72 PPI = 612 bp and (279 mm / 25.4 mm) x 72 PPI = 791 bp. To this page size, I have to add 7 mm margin, this meaning (7 mm / 25.4 mm) x 72 PPI = 20 bp. So, the complete command is this:
pdfcrop --margins 20 --bbox "0 0 612 791" input.pdf out_temp.pdf
The bbox argument takes values as left, bottom, right, top so right is the page width in bp and top is page height in bp. This is true for margins argument too. If you need different values for each margin you can specify them in the same manner.

It's time to check my intermediary document for the right page size. And since everything is OK (the page size of the intermediary document matches marks document), I will add the marks layer to it using PDF Chain, a pdftk GUI.

PDF Chain pdftk stamp
Overlay the marks and bleeds
Note that background and stamp should give you the same results, because the margin you added should be transparent and background should display through without issues. Anyway, to be absolutely sure, you should use Stamp mode, although this will appear on top of page content (but as I said there shouldn't be any page content there).

Here is a low resolution comparison of the initial document and the result.

Printer marks and bleeds to PDF in Linux
Original document (left) and result (right)
Note that from what I've seen, pdfcrop produced strange results with scanned documents (significant increase in file size). Another downside of it is that it requires you to download and install a big part of TeXLive distribution. But the good thing is it gets the job done.

No comments :

Post a Comment

Please read the comments policy before posting.