PDF editing

I think I am slowly going mad with frustration. I have been trying to blank out part of a graphic in a PDF file from work, to produce a new PDF file which will be readable in its edited form by anyone (Windows or Mac) who opens it. Lacking specific PDF-editing software, I have whited-out the undesirable part using Skim. AlI looks great until I open the file at work (Vista… don’t start me on that subject), when the edit is altogether absent. Fair enough – Skim is maybe adding my edit to the metadata, and the Acrobat Reader version at work is failing to recognise it. So, back at home, I try printing the Skim-edited file to DevonThink Pro, and saving it from there. This time, opening it at work causes the edit to appear – but as an overlay to the original, with a time lag that varies from near-instantaneous to a couple of seconds. It is very disconcerting to see the original contents flash before your eyes, and I am quite keen that this doesn’t happen in the final version if at all possible.

I do not want the original content of the blanked-out section of the graphic to appear in the final PDF, even for a flickering second or two. I do not want to buy PDF editing software just for this one tiny job (this is my employer’s first and only PDF deliverable). For various complex and insurmountable reasons, I cannot ask the original creator of the PDF to modify it and send it back to me, so I have to make the change myself. My Windows PDF software at work is limited to Acrobat Reader. At home on my Mac (Leopard), I have the usual PDF-related suspects (Preview, Skim, DevonThink Pro, Pagehand, for example), and I am prepared to try another utility if you recommend it, as long as it doesn’t cost anything (not because I am a skinflint, but because this is a one-off and I really don’t want to fork out cash for something which I intend to use only once and for a maximum of five minutes). I can’t help thinking that I am missing something very obvious, but can’t for the life of me see what it might be.

Please, does anyone know of a way of eliminating a small rectangular block from the front page of a PDF file, so that it will universally remain edited with no trace left of the original, and which can be saved as a PDF that can be read by anyone (i.e. no particular OS or software prerequisites)? Thank you!

Is the PDF file text-only and with a very basic format, or does it have lots of images etc? I ask only because if it was really basic and text-only, you could always convert it to text and edit that, and re-format it yourself.

Also, have you tried using Preview, and then from Preview using Print > Save to PDF (which I would have thought would flatten the file)?


You might look for a FedEx/Kinko’s or similar office service supplier or graphic arts house. They may have access to PDF-editing software, which you might be able to use for less than it would cost to actually buy the package.

A kludge that would work, but might degrade the quality, would be to print out the offending page, block out the graphic, and scan it into a new PDF. I think Preview allows you to shuffle full pages around, so you could splice the modified page in place of the original.


DevonTech has a free filter called PDF2RTFService. Using TextEdit, Pages, or any other Cocoa application, it will open a PDF file and save it as RTF. I’ve been most successful with TextEdit, and it works best with text conversion. Get it from DevonTech: Downloads: Free Stuff or at MacUpDate.

macupdate.com/info.php/id/17 … rtfservice

I was going to suggest that you get a trial copy of PDFPen Pro, and use that if the PDF in question is an image PDF rather than a text PDF, as PDFPen Pro has built in OCR which I have found to be pretty good, even with scanned PDFs with a non-white background. I think the basic PDFPen might also do OCR, but I don’t know. On the other hand, if you’re just wanting to trial it, it won’t really matter which you get provided it does OCR.

If it’s a text PDF, then you should be able to extract that text in Skim, or at worst, blank out the bit you want to remove and then use Skim to PDF … any Mac app that can print can print to PDF.

The basic version does OCR, see:http://www.smileonmymac.com/PDFpen/compare.html

There are some introductory videos on that page, too.

Thank you for the suggestions, everyone.

@Keith - Unfortunately, this page of the PDF file consists solely of images, and it is one such graphic image that I want to edit. I used Preview to change the page order, but the resultant PDF seems to save my Skim edit as an overlay rather than in a flattened state, which I suppose is rather clever but happens not to be what I want! Having said that, though, I have tried many iterations so can’t quite remember exactly which process produced each of my failed attempts, so I will try re-saving it in Preview and test it at the office tomorrow.

@kewms - Getting it done externally isn’t an option, I’m afraid, even if we had such places locally – no budget. I have just tried your suggestion of scanning the offending page, but the scan isn’t high enough quality to use in the document. Unfortunately, it’s the title page that I’m dealing with, so not one I want to be distorted! A good idea, though.

@druid - I didn’t know about PDF2RTFService; that looks useful for other things. Sadly, as above, I’m dealing with an image-laden page here, and all I get is a blank page when I try to open it via the service. Maybe because of the app I am trying to open it in? TextEdit doesn’t work for it, and I don’t have Pages, which are the two that DevonThink mention. (I have tried to download the trial version of Pages, but it doesn’t seem to let me, presumably because I tried it out before and it hasn’t deleted everything. If they bring out iWork 10 today, or whenever, I intend buying it, so Pages might yet turn out to be suitable.)

@xiamenese and @Prion - PDFpen looks as though it would be ideal if I had any budget for buying software for this. Unfortunately, the trial version stamps each page with the SmileOnMyMac logo which is a very nice logo but which would be even worse in this document than the content I am trying to remove!

@xiamenese - Skim seems to be remember its own changes, and these somehow seem to be preserved in the final version. When I open the file in a Mac app, there is no sign of the patch, and it looks as though the file has been edited successfully. When I open the file at work, on a Windows Vista machine with Acrobat Reader, I can clearly see the patch being applied to the page after it is opened. It is weird. And very annoying, because I can’t check it at home and there is a day’s delay every time I try something new.

Thank you for your ideas, everyone. Much appreciated. I’ll keep fiddling with it here at home, but I won’t be back in the office until tomorrow so can’t do any testing of further attempts until then. In the meantime, if you can think of anything else I could try, I would be very grateful!


Would it help to completely remove the front page? That can easily be done using the open source tool PDF Creator (www.pdfforge.org) on any Windows PC.

PDF Creator, however, will not help, if you need to preserve the rest of the front page.


Image only PDF == evil.

If you have adobe acrobat available some where you can extract the raw image. Once you have done that edit the image in gimp or whatever then add you new title page. That is the only way I know to do this. There may be some other tool that can actually extrCt the image but I am not aware of one.

As to why the skim route is failing you…

The image is rendered as is. Since it is one big blob in the front section of the PDF it has to complete before the next section can be rendered. If your whiteout block could be placed first in the PDF file you would see the image drawn behind you mask. Problem is PDF editing tools like skim can’t really change the render order of PDF files. I think this is a licensing/validation issue. There may be a PDF deconsrructor you can use but I don’t know of any other than acrobat. Sorry.

If you have GraphicConverter you can open the PDF, modify it, then resave it as a PDF. I think this will do what you want.

I just tried opening a PDF in GC then cropping out a rectangle, then resaving. When I opened the resulting PDF in Preview it was fine: no rectangle.

Worth a try.


I was just going to suggest Photoshop before I saw the above post. Photoshop will open a PDF in any resolution you wish (vector elements, such as text, will of course be converted into pixels). You can do any edits you want and then save back to PDF with no discernable change in quality, if you set the resolution in Photoshop high enough (300 dpi or more).

But Graphic Converter is of course cheaper (if you don’t have access to Photoshop) and more readily available. Is it still part of the basic OS X programme package, by the way?



Thank you everyone for your generous help. By combining recommendations and advice from lots of you, I think the problem is now solved. Sadly, I’m not at work so can’t do the final testing until tomorrow, but it is looking very promising.

@shorn and Spitfire31 - Graphic Converter was a great idea! (I don’t have PhotoShop.) I was able to edit the file as I needed. Due to my own stupidity, despite your sound advice, I neglected to check the resolution, and my first attempt (verified at work today) was perfect except for being at a resolution of 72! Yes, seriously. The text and graphic elements looked as though they were made of Lego bricks. So I have just redone it, at a sensible resolution, and it is looking great.

@fgrieser - The Graphic Converter trick created a new problem in that my PDF file had grown from 1.2 MB to 44 MB, which isn’t great for download/transfer etc. I was about to tear my hair out when I remembered what you had said about dropping the first page entirely. That wasn’t really a possibility for me, because the page in question is the title page, but your idea made me think of dropping the first page from the original file, then using Preview to paste in the newly edited first page from my Graphic Converter version. This gives me the best of both solutions – a nice new front page, and the rest of the document untouched. My final version is just 1.7 MB, which I can live with.

@jaysen - Thank you for explaining how the Skim changes were being applied/rendered. That makes a lot of sense. Image-only PDFs are indeed evil! I have aged a good five years this week…

So, fingers crossed that my new, shiny final version turns out tomorrow to be as good as I hope it will. Thank you, everyone, for your help. Not only have you (individually and severally) pointed me at a solution, but I now understand the process a lot better. Next time I apply for a job, I am going to ask at interview if my prospective employers have Acrobat, and if they don’t, I will seriously consider boycotting them!