About redaction and removing document elements
Redaction is the blacking out of sensitive text or pictures from a PDF file. Remove elements (also accessed via the Security tab) serves to remove hidden or background information.
Due to possible legal consequences of exposing such information, it is common to redact document contents before public release. The PDF format is complex, and may contain more information than is immediately visible. Use redaction to prevent exposure of sensitive information.
A key concept is that Deletion is not equal to Redaction. The information you delete from a PDF with the Delete command is not actually cleared from the document permanently and can almost always be recovered.
The topics below describe the involved features and their limitations.
Redaction
Redaction lets users sanitize PDF documents they want to release. It is usually a two-step process: first you select and mark items to be removed, then after re-checking you apply the redaction. See the appearance of marked and redacted text under Redacting Content. With Redaction tools, you can:
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Select and remove text, vector graphics, bitmap images, multi-object areas or complete pages.
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Search and remove specific text within the current document.
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Remove all references of certain content from the current document.
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Show redacted areas as unreadable highlights, optionally overlaid with a Secrecy Coding or a predefined custom text.
Document Inspection (removing document elements)
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Remove all comments from a document.
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Remove document properties and other metadata.
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Remove links, destinations, attachments and more.
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Remove embedded indexes (under Remove embedded non-display data) that may still contain redacted text strings.
Redaction and document flattening
Documents can also be prepared for public distribution by flattening the PDF file. Flattening can remove layers, annotations or mark-ups of specified types from the document, or transform them into document objects, so they no longer appear in the Comments panel. You can select Redaction as a choice for flattening. In this case:
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Black rectangles cover redacted text; they can be selected and moved, but the underlying content cannot be seen or searched. In other words, redaction remains intact.
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Black rectangles cover text marked for redaction, but it is not actually redacted; the rectangles can be selected and moved, but then the underlying text or object becomes visible, so no redaction has been performed.
Redaction by searching
Redaction is combined with the searching function in the following features:
- Search and Redact: Found items are marked for redaction, as described in Searching and Redacting Text. Select this option from the Document menu.
About redacting packages and portfolios
Packages and Portfolios can be redacted by searching.
Packages containing only PDF files can be redacted in this way, but packages containing package files may not be correctly redacted.
When redaction is applied to a portfolio, only the PDF files in the portfolio will be redacted. In general, it is safer to unpack files before redacting them, because this enables redaction by selection and the results can be examined more easily.