# How to blur or greek text in a PDF? **URL:** \ **Category:** Factual Questions\ **Created:** [November 23, 2009, 11:13pm UTC](https://boards.straightdope.com/t/how-to-blur-or-greek-text-in-a-pdf/518705 "2009-11-23T23:13:30Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [November 23, 2009, 11:13pm UTC](https://boards.straightdope.com/t/how-to-blur-or-greek-text-in-a-pdf/518705/1 "2009-11-23T23:13:30Z")
So I am putting together a sort of sales brochure/outline to show prospective clients. I want to display samples of real work prepared for clients… but I don’t want to reveal any confidential information when I do that. I know that I can use Acrobat to black out text by drawing a solid box over the text. If I have to, this is what we’ll do. However, I was hoping that there’d be a way to blur or greek the potentially identifying information without having to black things out entirely. That way, the samples will look more natural - only on a closer inspection would a prospective client know that we’ve concealed names and identities. I already have Acrobat Pro 8 for Mac (OS X 10.6), but I’d be willing to upgrade or buy something else if that feature was there. ---
**Author:** ![President\_Johnny\_Gentle](https://avatars.discourse-cdn.com/v4/letter/p/5f9b8f/32.png) [@President\_Johnny\_Gentle](https://boards.straightdope.com/u/President_Johnny_Gentle)\ **Post date:** [November 23, 2009, 11:37pm UTC](https://boards.straightdope.com/t/how-to-blur-or-greek-text-in-a-pdf/518705/2 "2009-11-23T23:37:13Z")
I’m not sure how to handle this, short of creating new documents. However, unless things have changed in the last couple years, [do not just put boxes over confidential information](http://www.law.com/jsp/law/international/LawArticleIntl.jsp?id=900005549014). The underlying information is still there. ---
**Author:** ![Khadaji](https://avatars.discourse-cdn.com/v4/letter/k/9e8a1a/32.png) [@Khadaji](https://boards.straightdope.com/u/Khadaji)\ **Post date:** [November 23, 2009, 11:43pm UTC](https://boards.straightdope.com/t/how-to-blur-or-greek-text-in-a-pdf/518705/3 "2009-11-23T23:43:17Z")
PDF will allow you to embed images. What you could do is take a screen shot of the brochure you want, blur the text on the image and then embed the image into PDF. ---
**Author:** ![BorgHunter](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@BorgHunter](https://boards.straightdope.com/u/BorgHunter)\ **Post date:** [November 23, 2009, 11:56pm UTC](https://boards.straightdope.com/t/how-to-blur-or-greek-text-in-a-pdf/518705/4 "2009-11-23T23:56:38Z")
> [@Khadaji](#): > > PDF will allow you to embed images. What you could do is take a screen shot of the brochure you want, blur the text on the image and then embed the image into PDF. Seconded. If you obscure the information in a way that keeps it in the source of the PDF, you’ve only superficially removed it from view—in a PDF, all that information is still there, for example, if you draw a box over the text, or put the text there then apply a blur, etc. If you don’t want to play around with images (and they can make a PDF unusually large compared to text, especially if you’re dealing with large, high quality images), you could always just do a search-and-replace for your identifying information with generic stuff—Charles B. Client becomes John Q. Public, 1060 W Addison St becomes 123 Fake St, etc. ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [November 24, 2009, 12:06am UTC](https://boards.straightdope.com/t/how-to-blur-or-greek-text-in-a-pdf/518705/5 "2009-11-24T00:06:41Z")
Thanks for the suggestions. I should have been a little more clear about the final application - I’ll be printing the documents and using only the printed version around third parties. So I’m not worried about whether the electronic data is eliminated, just about what would be put onto paper by my printer. I am still hoping there is a magic solution - like a box with blur settings rather than transparency settings - but that may not exist. ---
**Author:** ![minor7flat5](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/minor7flat5/32/258_2.png) [@minor7flat5](https://boards.straightdope.com/u/minor7flat5)\ **Post date:** [November 24, 2009, 12:22am UTC](https://boards.straightdope.com/t/how-to-blur-or-greek-text-in-a-pdf/518705/6 "2009-11-24T00:22:27Z")
> [@dracoi](#): > > I already have Acrobat Pro 8 for Mac (OS X 10.6), but I’d be willing to upgrade or buy something else if that feature was there. You already have the feature you are looking for. The word you are looking for is _redaction_, and Acrobat Pro 8 for Mac does this in spades. Go to **View / Toolbars / Redaction**. Also, **Advanced / Redaction / …** [Here’s my article on this exact subject](http://paperjammed.com/2009/04/21/keeping-your-secrets-to-yourself%E2%80%94what-can-your-shared-documents-tell-others/) from some months back, with some examples showing exactly what happens when you do PDF redaction poorly. Please read so you see what you are up against. ---
**Author:** ![Khadaji](https://avatars.discourse-cdn.com/v4/letter/k/9e8a1a/32.png) [@Khadaji](https://boards.straightdope.com/u/Khadaji)\ **Post date:** [November 24, 2009, 12:40am UTC](https://boards.straightdope.com/t/how-to-blur-or-greek-text-in-a-pdf/518705/7 "2009-11-24T00:40:53Z")
Why not just change the font to webdings or wingdings? If you don’t embed the fonts, I _think_ PDF will only show little rectangles (well, OK, that is what it did when I tried it here, but I was using Nitro PDF professional and not a real version of Acrobat.) ---
**Author:** ![Punoqllads](https://avatars.discourse-cdn.com/v4/letter/p/d2c977/32.png) [@Punoqllads](https://boards.straightdope.com/u/Punoqllads)\ **Post date:** [November 24, 2009, 1:18am UTC](https://boards.straightdope.com/t/how-to-blur-or-greek-text-in-a-pdf/518705/8 "2009-11-24T01:18:39Z")
> [@dracoi](#): > > I am still hoping there is a magic solution - like a box with blur settings rather than transparency settings - but that may not exist. There is a magic solution. Specifically, magic marker. Old school redaction. ---
**Author:** ![Lance\_Turbo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lance_turbo/32/6156_2.png) [@Lance\_Turbo](https://boards.straightdope.com/u/Lance_Turbo)\ **Post date:** [November 24, 2009, 1:32am UTC](https://boards.straightdope.com/t/how-to-blur-or-greek-text-in-a-pdf/518705/9 "2009-11-24T01:32:29Z")
I would replace the text on the page with text from [this page](http://www.lipsum.com/). ---
**Author:** ![minor7flat5](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/minor7flat5/32/258_2.png) [@minor7flat5](https://boards.straightdope.com/u/minor7flat5)\ **Post date:** [November 24, 2009, 2:02am UTC](https://boards.straightdope.com/t/how-to-blur-or-greek-text-in-a-pdf/518705/10 "2009-11-24T02:02:26Z")
> [@Lance\_Turbo](#): > > I would replace the text on the page with text from [this page](http://www.lipsum.com/). Note: the PDF format supports incremental nondestructive updates. In other words, a PDF editor can completely change the appearance of a document by appending the changes, while retaining the original version embedded within. (I understand that the OP is really only interested in printing documents, but I would discourage editing the file to make it appear innocuous and then printing: as soon as you are done editing, the doctored file will be forgotten and will appear to be innocent of all secrets. Somebody might some day send the file via email.) Anyway, here’s a fairly geeky treatment of the PDF file structure: [Portable Document Format: An Introduction for Programmers](http://www.mactech.com/articles/mactech/Vol.15/15.09/PDFIntro/) > [@](#): > > The trailer, it turns out, plays an important role in the way PDF implements incremental updating. The key concept to understand here is that a PDF file is never overwritten, only added to. That goes for all portions of the PDF file - even the trailer itself, and the end-of-file marker. In other words, a multiply-updated PDF document may contain multiple trailers - and multiple end-of-file markers! (There may be numerous occurrences of %%EOF.) Each time the file is edited, an addendum is written to the tail of the file, consisting of the content objects that have changed, a new xref section, and a new trailer containing all the information that was in the previous trailer, as well as a /Prev key specifying the byte offset (from the beginning of the file) of the previous xref section. The cross-reference info will then be distributed across more than one xref section. To access all of the cross-references, the reader must walk the list of /Prev keys in all the trailers, in reverse order. ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [November 24, 2009, 2:03am UTC](https://boards.straightdope.com/t/how-to-blur-or-greek-text-in-a-pdf/518705/11 "2009-11-24T02:03:44Z")
> [@minor7flat5](#): > > Here’s my article on this exact subject from some months back, with some examples showing exactly what happens when you do PDF redaction poorly. Please read so you see what you are up against. Excellent article, and the redaction feature does just what I want. I would never have thought of looking for that term in the help files! I’m using the option to replace with text so I can keep the surface look I want - without big black marks through everything - and still use gibberish text that won’t reveal anything important. And thanks to everyone else as well. ---
**Author:** ![bannerrefugee](https://avatars.discourse-cdn.com/v4/letter/b/c68b51/32.png) [@bannerrefugee](https://boards.straightdope.com/u/bannerrefugee)\ **Post date:** [November 24, 2009, 2:08am UTC](https://boards.straightdope.com/t/how-to-blur-or-greek-text-in-a-pdf/518705/12 "2009-11-24T02:08:00Z")
In Acrobat 9 the redaction feature also allows you to make the redaction various colours. For example if the background is white it is easy to make the redactions invisible. beat me to it ---
**Author:** ![minor7flat5](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/minor7flat5/32/258_2.png) [@minor7flat5](https://boards.straightdope.com/u/minor7flat5)\ **Post date:** [November 24, 2009, 2:34am UTC](https://boards.straightdope.com/t/how-to-blur-or-greek-text-in-a-pdf/518705/13 "2009-11-24T02:34:01Z")
> [@dracoi](#): > > I’m using the option to replace with text so I can keep the surface look I want - without big black marks through everything - and still use gibberish text that won’t reveal anything important. Just make sure you are doing this using the proper redaction tools and not “TouchUp Text Tool” and its brethren. I did a simple experiment a few minutes ago: [ul][li]Printed this thread to PDF[/li][li]Edited with Acrobat Pro[/li][li]Replaced the OP with text of my choosing. At this point, the PDF document appeared to have been irrevocably changed.[/li][li]Opened the file in a binary editor and searched for “%%EOF”. There were two instances of this string, the first from the original file, and the second from my editing session.[/li][li]Deleted all text/bytes following the first EOF.[/li][li]Reopened the file in my favorite PDF viewer: it was back to the original![/ul][/li]Some PDF editors do, in fact, rewrite documents from scratch, but Acrobat seems to append changes to the end, in a totally reversible manner. (and thanks for the kind word!) ---
**Author:** ![minor7flat5](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/minor7flat5/32/258_2.png) [@minor7flat5](https://boards.straightdope.com/u/minor7flat5)\ **Post date:** [November 24, 2009, 4:50am UTC](https://boards.straightdope.com/t/how-to-blur-or-greek-text-in-a-pdf/518705/14 "2009-11-24T04:50:14Z")
I did a writeup of my short experiment above, complete with screenshots. It was actually kind of cool (and slightly distressing) to see that the original PDF document really does live untouched within the modified one. [Keeping your secrets to yourself—old changes lingering in your PDF files](http://paperjammed.com/2009/11/23/keeping-your-secrets-to-yourself-old-changes-lingering-in-your-pdf-files/) ---
**Author:** ![Avumede](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/avumede/32/7235_2.png) [@Avumede](https://boards.straightdope.com/u/Avumede)\ **Post date:** [November 24, 2009, 4:54am UTC](https://boards.straightdope.com/t/how-to-blur-or-greek-text-in-a-pdf/518705/15 "2009-11-24T04:54:14Z")
I should also note that blurring can be cracked, even without anything besides the graphics. But if the info you are blurring isn’t super confidential, I wouldn’t worry about it. ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [November 24, 2009, 5:35pm UTC](https://boards.straightdope.com/t/how-to-blur-or-greek-text-in-a-pdf/518705/16 "2009-11-24T17:35:50Z")
> [@minor7flat5](#): > > Just make sure you are doing this using the proper redaction tools and not “TouchUp Text Tool” and its brethren. One of the problems with the TouchUp Text Tool (aside from security) is that it screws up the alignment and spacing of text in the documents. Otherwise, it would have worked for my purposes of printing the documents. But, no, I used the proper Redaction tools. They’re going to get a lot of use from now on… I’m a little surprised I hadn’t learned about them before. ---
**Author:** ![Dickerman](https://avatars.discourse-cdn.com/v4/letter/d/8baadc/32.png) [@Dickerman](https://boards.straightdope.com/u/Dickerman)\ **Post date:** [November 24, 2009, 8:04pm UTC](https://boards.straightdope.com/t/how-to-blur-or-greek-text-in-a-pdf/518705/17 "2009-11-24T20:04:22Z")
> [@minor7flat5](#): > > It was actually kind of cool (and slightly distressing) to see that the original PDF document really does live untouched within the modified one. Note that if you perform a “Save As” operation in Acrobat, it’s possible to have Acrobat remove the old data. ---
**Author:** ![Canadjun](https://avatars.discourse-cdn.com/v4/letter/c/76d3ee/32.png) [@Canadjun](https://boards.straightdope.com/u/Canadjun)\ **Post date:** [November 24, 2009, 9:38pm UTC](https://boards.straightdope.com/t/how-to-blur-or-greek-text-in-a-pdf/518705/18 "2009-11-24T21:38:35Z")
> [@Punoqllads](#): > > There is a magic solution. Specifically, magic marker. Old school redaction. Magic marker isn’t as good as it appears at first glance. I’ve seen many documents that are a few years old where confidential information that had been redacted with magic marker wasn’t that hard to read because the magic marker ink had faded. You need to photocopy the document following redaction and then keep only the photocopy.