How to edit PDF files
There are many ways in which a PDF file can be edited, using a wide range of editor tools that are on the market. This page focuses on the typical editing needs in a prepress environment. The following types of changes are discussed:
* Text manipulations: how to edit text in a PDF.
* Image editing: how to edit an image in a PDF file or replace it.
* Page related changes: how to delete pages, change their order or rotate them.
* Altering a PDF file: how to merge pages from separate PDF files, edit password protected files or add bleed.
* Color editing: how to convert a PDF from color to black&white.
At the bottom is also a small overview of PDF editing applications.
Always keep in mind that PDF files are an accurate representation of a document. They are meant for output or on-screen viewing. They are not intended to be intermediate files that can still be edited. There are programs on the market that allow you to change the content of a PDF file and there are applications or plug-ins that can extract the content of a PDF so that you can insert this data into a new document. Altering PDF files is a last resort – whenever possible the original source file should be corrected and a new PDF generated. This is especially true for documents that will be reused at a later date!
Changing text
How to edit text in a PDF
Within a PDF file text is essentially stored as single lines. The concept of text flowing from one line to another within a column does not exist. This makes it fairly difficult to edit text unless you rely on special tools that somehow manage to intelligently predict how text flows within a document
* Adobe Acrobat & Acrobat Professional have a TouchUp Text tool for small text modifications. When you add or delete text, it will not reflow the text in the entire column. Some releases of Acrobat have a pretty bad reputation when it comes to the TouchUp Text tool, with users reporting weird behavior of the edited or remaining text once the tool is used. Use this tool only if there is no way to edit the original source file and recreate a PDF.
* Even though Adobe Illustrator can open a surprisingly large range of PDF files, it is a bad choice if you want to edit text. Illustrator automatically uses its own fonts instead of fonts embedded in a PDF. This can lead to text reflows even if you leave text untouched.
* For extensive text editing, Infix PDF Editor is an interesting product. I used it to add text to a book and found the reflow capabilities of the application quite impressive.
Changing images
How to edit an image in a PDF file
There are several high-end tools on the market that are optimized for this type of task. It is however surprising how much you can already achieve with Adobe Acrobat, provided you also have applications like Photoshop and Illustrator. In the ‘Touchup’ Preferences of Acrobat you can define which image and object editor you want to use from within Acrobat. Once this has been defined, you can use the Touchup Object Tool to select an object, context-click it and select the Edit option. In the case of an image, the default application (Photoshop on my set-up) opens the image. After changing the image, it is re-embedded in the PDF file.
Acrobat touchup object tool (far right)
Acrobat 8 Touchup Object Tool (far right)
How to replace an image in a PDF file
The above procedure for editing images can also be used to replace graphics. Use the Touchup Object Tool to open an image or artwork in Photoshop or Illustrator. Replace the content with the new image or artwork that you want to insert. In the case of images it is best to maintain the resolution of the image you originally opened. Once the content is swapped use Save to reinsert it back into the PDF. There are other ways of swapping images which get discussed in this b4print thread.
Changing pages
How to delete pages, swap or rotate them
Adobe Acrobat can do all of this but there are most likely cheaper solutions around. I never bothered to check.
Changing color
How to convert a PDF from color to black&white
Most recent versions of Acrobat Professional can be used to convert a PDF to B&W. In Acrobat 9 Pro select Advanced > Print production > Convert Colors. Activate the option ‘Convert Colors To Output Intent’ and scroll all the way down in the list of profiles until you find the grayscale ones. Select an appropriate one and click OK to start the conversion.
There are also some Acrobat plug-ins that can do this. I have used PitStop but prefer Quite-a-box-of-tricks which seems to be both faster and more reliable (in the past PitStop sometimes left some objects untouched).
Changing the entire PDF file
How to merge pages from separate PDF files
There is a separate page on this site dedicated to this topic.
How to edit a password protected PDF file
The PDF standard supports an extensive set of security features to prev