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!
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.
One thing to keep in mind is that there is a mechanism in PDF to store a copy of the text in its logical reading order. If you edit the text in such a so-called ‘tagged PDF’ you are only modifying the visible copy, not the hidden duplicate. That means that even after removing part of the text, it still may show up in search results!