In daily life, we always need to share PDF files. These PDFs may contain sensitive information which we don’t want others to see. This might be bank account information, numbers, contracts, medical records, etc.
Learning how to redact a PDF will help to get around this problem.
Use redaction function in Adobe Acrobat is what most people recommended. But there are actually multiple other ways to redact a PDF. For instance, Mac’s Preview includes redaction feature that can black out text permanently in PDF files. And for Windows users, one can easily use any free annotation tools to hide the information and then flatten the file so that others cannot edit or remove it.
To know more good ideas, continue reading this article! Here we’ll show you how to redact a PDF with or without Adobe Acrobat Pro. And we are happy to tell you that most of the methods are totally free.
Cisdem PDFMaster
Free Download macOS 11 or later 
Free Download Windows 11/10/8/7
Redaction means removing sensitive or confidential information from a PDF permanently. It doesn’t allow to recover the redacted content or undo the redaction. So before the redaction process, you’d better save a copy of the PDF document under a different name.
We all know one can use the redaction tool in Adobe Acrobat to redact a PDF file, but its UI design is unfriendly to a novice, and it costs $239.88 per year to activate the redact function.
Cisdem PDFMaster is considered the best alternative to Adobe Acrobat to redact a PDF. It is an all-in-one PDF toolkit that includes everything you need in Adobe Acrobat at a fifth of the price. With its built-in redaction feature, users can redact any specific part of a PDF (no matter the PDF is scanned, signed or protected) and make comments on the redaction mark. And if you need to redact multiple pages at once, this software provides 3 page range options for your choice. Once the redaction is applied to the document, no one can retrieve its content.
Besides redacting a PDF, you can also utilize PDFMaster to create and convert PDF, edit PDF, annotate PDF, protect and unlock PDF, build forms, OCR scanned documents, add digital signatures, combine and split PDF, etc.
Download and launch Cisdem PDFMaster on your Mac or computer.
Free Download Windows 11/10/8/7 Free Download macOS 10.13 or later
In general, a PDF document that contains a digital signature does not allow any modifications to it, including marking the redaction. If you are the signer, find the unsigned original, redact it, and sign it again digitally. If you don't keep the original, don’t worry, PDFMaster can also help you with this problem.
For subscribed Adobe users, the redaction tool in Adobe Acrobat Pro will easily redact sensitive information in PDF.
Mac’s build-in PDF reader - Preview can also work as a handy free PDF editor which comes with PDF redaction tool. Note that this redaction tool was introduced in macOS 11 “Big Sur”. If your Mac system is in macOS 11 or later, you can just follow the steps below. Or if not, we also introduced how you can use the marker tool to redact text in PDF on Mac.
For Windows users, LibreOffice is a totally free tool that supports redact and black out private information. It has built a redact function that supports adding rectangle, free form to hide information in PDF and one can choose to export the redacted PDF in white or black.
The downside of this option is that sometimes it will load PDF files in a mess (you can see in the below screenshots, our PDF shows a strange logo in the top) and the output quality has a lower resolution than the original PDF.
Just like black out information in a paper and then scan it, we can also use free PDF annotation tools like PDF-XChange Editor to blackout information in PDF files and then use Microsoft print to flatten the PDF so that others who receive the PDF can not move the black rectangle, delete it or make it transparent.
Download the free portable version of PDF-XChange Editor here: you can find the download link right below the version information, just choose 32 bit or 64 bit according to your needs.
iLovePDF is a PDF service well reviewed by a large number of users, which offers both web-based tools and desktop application. Its online tools available are totally free to use. And recently, it has added 3 new advanced features for online free uses, including OCR PDF, Compare PDF and Redact PDF. You can upload a PDF file smaller than 400 MB when using the redaction tool.
The disadvantage of iLovePDF is that it merely supports redacting the text in a PDF, while there is no way to select the images or other non-text elements.
AvePDF is a web-based application that provides 50+ tools to process any document online. Other than redacting PDF, this online site offers high-level features such as capturing document from scanner, annotating a PDF, reducing PDF file size, hyper-compression, e-signature, adding links to page, and advanced OCR.
It has a maximum upload size of 128MB, much larger than the other online sites, which is sufficient for most uses. Besides, all documents will be automatically deleted from this web after 30 minutes.
Limitation of free version: 2 tasks per 6 hours for free.
In PDF publishing, the process of blacking out confidential information is called redacting. It is thought that the word was originally derived from the act of blacking out sensitive information in a paper with black ink.
Some sites and tools claim that they can redact PDF, but the truth is that they only blackout the information with highlighters or shapes and focus on the visual outcome, but actually this information can be recovered and located by others.
Rest assured. There are two steps you can take to verify that all sensitive information has been securely redacted:
You can try to search for any keywords or phrases you have redacted in the PDF file and check if it can still be searched, if yes, then this is not a real redaction. (Shortcuts: Ctrl + F keys)
We can also try to copy and paste the blackout information and see if it can be copied and pasted.
These two kinds of black out in the PDF documents look the same when viewed with a PDF reader. However, when you select each blacked out part, copy and paste them to Notepad, you will get the following result.
From the above part, you know that if you use a real redaction tool, the information is permanently deleted and unrecoverable, so be sure to make a copy of the document before the redaction.
There are a part of users pointing out that they can’t redact text in PDF and don’t know why. If you are in a situation where the redaction tool button turn gray and doesn’t allow you to click on it. Go to File > Properties > Security, you can see if the file has some permissions set before. There is a high probability that the file has been set with permission to prohibit comments, so that the text cannot be redacted. In this case, find the permission creator to unlock the restriction. If the file is restricted to editing text only, redaction will generally not be affected. In addition, both scanned files and interactive files can successfully apply redaction.
One can also add password to a PDF file. And there are two kinds of PDF password
PDF Open Password: As its name suggests, this means you add a password to a PDF file and control who can open the PDF file.
PDF Permission Password: With a permission password, you can set limit on PDF printing, copying, pasting, editing, etc.
You can use tools like preview and PDFMaster to add password to a PDF file.
And that's all there is to redacting a PDF. All these 7 methods can keep sensitive information in PDF away from those who shouldn't be able to view it.
PDF security is a vital part of business process. When redacting a PDF document, don't just black it out, make sure that use professional PDF redaction software to permanently erase the data.
If you want an easy and safe offline option, Cisdem PDFMaster is your best PDF assistant, it can safely redact a PDF file and offer all of its functions for users to test for 7 days. Just download and see how it can help you edit and redact a PDF file.
Free Download macOS 11 or later Free Download Windows 11/10/8/7
Earlier than macOS 11, click here
Bianca is a senior tech editor and strategist at Cisdem with Over 10 years of experience on PDF related solutions which covers all document editing, annotating, converting and managing etc.
Frank
I didn't use Adobe because it's really expensive for me, and I need a more affordable editor to redact my PDF. I think the professional editor in Cisdem you mentioned can meet my needs.